SCHRES-06216; No of Pages 8 Schizophrenia Research xxx (2015) xxx–xxx

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Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy Vincent Chow a,b,c, Caroline Reddel a,b,c, Gabrielle Pennings a,b,c, Elizabeth Scott d, Tundra Pasqualon e, Austin C.C. Ng b,c, Thomas Yeoh b, Jennifer Curnow a,c,f, Leonard Kritharides a,b,c,⁎ a

ANZAC Research Institute, Sydney, Australia Department of Cardiology, Concord Repatriation General Hospital, Sydney Local Health District, Sydney, Australia University of Sydney, Australia d Brain & Mind Research Institute, University of Sydney, Australia e Department of Psychiatry, Croydon Health Centre, Sydney, Australia f Department of Haematology, Concord Repatriation General Hospital, Sydney Local Health District, Sydney, Australia b c

a r t i c l e

i n f o

Article history: Received 21 January 2014 Received in revised form 4 December 2014 Accepted 6 December 2014 Available online xxxx Keywords: Schizophrenia Blood coagulation test Coagulation Thrombosis Fibrinolysis

a b s t r a c t Background: Patients with schizophrenia are at increased risk of venous thromboembolism. The mechanisms underlying this association are poorly understood. Aims: We investigated whether there is a global hypercoagulable state in patients with schizophrenia utilising the overall haemostatic potential (OHP) assay which assesses overall coagulation potential (OCP), haemostatic potential (OHP) and fibrinolytic potential (OFP). Method: Citrated plasma was collected for OHP assays from patients with schizophrenia on long-term antipsychotic treatment and compared with healthy age- and sex-matched controls. Time courses of fibrin formation and degradation were measured by spectrophotometry (absorption of 405 nm) after the addition of tissue factor and tissue plasminogen activator to plasma. Results: Ninety patients with schizophrenia (antipsychotic treatment-15.9 ± 9.7 years) and 30 controls were recruited. Patients with schizophrenia had higher rates of smoking and levels of inflammatory markers (highsensitivity C-reactive protein and neutrophil-to-lymphocyte ratio) than controls. Whilst D-dimer, fibrinogen and platelet count did not differ between patients with schizophrenia and controls, the OCP (54.0 ± 12.6 vs 45.9 ± 9.1, p = 0.002) and OHP (12.6 ± 5.8 vs 7.2 ± 3.7, p b 0.001) were higher, and OFP was lower (76.6 ± 9.8% vs 84.9 ± 6.4%, p b 0.001) in patients with schizophrenia, implying both a hypercoagulable and hypofibrinolytic state in these patients. Importantly, abnormalities in overall coagulation were independently predicted by levels of plasminogen-activator-inhibitor-1, fibrinogen, platelet count, inflammatory markers and plasma triglycerides, suggesting a multifactorial aetiology. Conclusion: Patients with schizophrenia have evidence of a global hypercoagulable and hypofibrinolytic state which may contribute to their increased risk of venous thromboembolism. © 2015 Elsevier B.V. All rights reserved.

1. Introduction Patients with schizophrenia have an increased risk of venous thromboembolic disease and other cardiovascular diseases. This increased risk is attributed to multiple factors including conventional risk factors for cardiovascular disease such as smoking, obesity, the metabolic syndrome and systemic inflammation. Other specific factors may include immobility, catatonia during severe illness and the use of antipsychotic medications (both conventional and atypical). Early case ⁎ Corresponding author at: Department of Cardiology, Concord Repatriation General Hospital, Level 3 West, Hospital Road, Concord, NSW 2139, Australia. Tel.: +61 2 9767 7359; fax: +61 2 9767 6994. E-mail address: [email protected] (L. Kritharides).

reports of increased incidence of VTE amongst patients receiving conventional antipsychotic medications (Varia et al., 1983; Roche-Bayard et al., 1990) were confirmed by larger case–control studies which reported a seven-fold increase in risk of VTE (Zornberg and Jick, 2000) and 13-fold increase risk of fatal pulmonary embolism (PE) (Parkin et al., 2003). There is some evidence of higher risk amongst new users and those receiving atypical antipsychotic medications (Walker et al., 1997; Hagg et al., 2009; Parker et al., 2010). VTE has a reported early case fatality rate of 7–11% (Stein et al., 2004), and a reported 5-year cumulative mortality rate of up to 32% (Ng et al., 2011). An increased risk of VTE occurs when at least one of Virchow's triad is present (i.e. vascular endothelial damage, stasis of blood flow, and/or hypercoagulability of blood) (Anderson and Spencer, 2003). In the most recent VTE guidelines and current literature, hypercoagulability has

http://dx.doi.org/10.1016/j.schres.2014.12.042 0920-9964/© 2015 Elsevier B.V. All rights reserved.

Please cite this article as: Chow, V., et al., Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2014.12.042

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V. Chow et al. / Schizophrenia Research xxx (2015) xxx–xxx

been shown to increase the risk of VTE by 2–9 fold in the general population (Rogers et al., 2012; Authors/Task Force et al., 2014). Appropriate risk stratification for VTE risk and development of prevention strategies requires a clear understanding of the mechanisms involved, and very few studies have directly quantified or addressed the mechanisms of increased thrombotic risk in patients with schizophrenia receiving long-term antipsychotic treatment. Overall coagulation and fibrinolysis are determined by the interplay between pro-coagulant factors such as factor VIII (FVIII) and plasminogen activator inhibitor type-1 (PAI-1), and anti-coagulant factors such as protein C and protein S. FVIII is an important component of the intrinsic coagulation pathway and is responsible for the amplification of the coagulation cascade after initial thrombin generation (Furie and Furie, 2008). PAI-1 is one of the most important inhibitors of the plasma fibrinolytic activity and is raised in inflammatory states, atherosclerosis and obesity (Cesari et al., 2010). Elevated levels of FVIII and PAI-1 have been shown to increase the risk of VTE by 4.8-fold (Koster et al., 1995a; Jenkins et al., 2012b) and 1.6-fold (Meltzer et al., 2010) respectively. Proteins C and S exert anticoagulant effects by inactivating coagulation factors V and VIII. Patients with protein C and S deficiencies have a 7.3–8.5 fold lifetime increased risk of VTE (Koster et al., 1995b). Previous studies have found inconsistent associations between FVIII levels (Bank et al., 2007; Jenkins et al., 2012a), protein C and S levels (Mahmoodi et al., 2010; Bucciarelli et al., 2012), PAI-1 levels (Yukizawa et al., 2012), direct effects of antipsychotics (Carrizo et al., 2008) and VTE risk in these patients (Reitter-Pfoertner et al., 2013). Conventional testing for thrombophilia involves screening for specific individual abnormalities in haemostasis which can be costly and prone to misinterpretation (Jennings et al., 2005). Consequently, current guidelines do not recommend routine screening for heritable thrombophilia in asymptomatic individuals (Baglin et al., 2010; Middeldorp, 2011a). As the underlying biological mechanisms by which patients with schizophrenia develop VTE are likely multifactorial, these may lend themselves to investigation by global coagulation assays rather than by measuring individual factors. The overall haemostatic potential (OHP) assay is a simple, validated and inexpensive global coagulation assay that detects both the dynamic coagulation and fibrinolytic potential of plasma samples. The underlying principle of the OHP assay determines whether the hypercoagulable state is due to increased fibrin generation (hypercoagulability), reduced fibrinolysis (hypofibrinolysis), or a combination of these. Fibrinolysis is the process of degradation of a fibrin blood clot and limits thrombus extension beyond the site of endothelial damage. The fibrinolytic system is a complex cascade that controls the dissolution of the fibrin blood clot into soluble fibrin degradation products and consists of many factors including plasminogen, plasminogen activator, PAI-1 (Van De Craen et al., 2012). The fibrinolytic potential as measured in the OHP assay measures the aggregate effect of these components. It has been shown to be useful in identifying hypercoagulable states in patients with acute coronary syndromes, autoimmune diseases and following cardiac bypass surgery (Vedin et al., 2005; Curnow et al., 2007; Reddel et al., 2013). The primary aim of this study was to investigate whether patients with schizophrenia taking long-term antipsychotics demonstrated a global hypercoagulable state as determined by the OHP assay (He et al., 1999, 2001; Curnow et al., 2007). The secondary aim of the study was to assess for clinical characteristics and laboratory markers associated with alterations in global coagulation and fibrinolysis. 2. Methods and materials 2.1. Study population From January 2010 to December 2012, 90 consecutive patients with schizophrenia who attended a specialist clinic established for the

cardiac evaluation and screening of patients with schizophrenia receiving antipsychotic treatment were recruited. The control groups comprised of healthy volunteers of similar age and gender with no prior history of schizophrenia or VTE or ischaemic heart disease and those not receiving antipsychotic or long-term anticoagulation medications. Amongst the 90 patients with schizophrenia, there were no patients receiving conventional neuroleptics. 68/90 (76%) of patients were receiving clozapine treatment, and the remaining 22 patients received the following treatment: olanzapine (6), aripiprazole (4), quetiapine (4), paliperidone (4), risperidone (2), amisulpride (1) and zuclopenthixol (1). Patients were excluded if they: 1) were prescribed an antipsychotic medication for less than one year; 2) deemed noncompliant with antipsychotic medications based on psychiatry reviews and serum clozapine levels for patients receiving this drug; 3) had previous history of VTE (PE and/or deep vein thrombosis [DVT]); 4) had symptoms suggestive of ischaemic heart disease and/or were found to have ischaemic heart disease on functional testing or 5) receiving long-term oral anticoagulation. All patients with schizophrenia met DSM-IV diagnostic criteria for a schizophrenic disorder according to the guidelines of the American Psychiatric Association (1994). This cross-sectional study was approved by the institutional Human Ethics Committees.

2.2. Overall haemostatic potential (OHP) assay Blood samples were collected by venipuncture from the cubital vein with a 21 gauge butterfly needle. The tourniquet was removed and the first 3 ml of blood was discarded. Blood was collected into BD Vacutainer 0.109 M sodium citrate tubes (Becton-Dickinson, Franklin Lakes, NJ, USA) then centrifuged for 10 minutes (min) at 23 °C and 2500 g (Eppendorf 5804 R, USA). The plasma supernatant was centrifuged under the same conditions to produce platelet-poor plasma. We used a modified OHP assay based on that described by Blomback (He et al., 1999, 2001; Curnow et al., 2007). Fibrin time curves were generated in microtiter plate wells and plasmas were tested in duplicate. The OHP assay blank buffer consisted of Tris (tris(hydroxymethyl) aminomethane), NaCl and CaCl2, and purified water was used to make the buffer in the OHP assay. The concentrations of the reagents in the buffer were: Tris—66 mM, NaCl—130 mM and CaCl2—35 mM. The buffer was adjusted to a pH of 7 and stored at 4 °C. The overall coagulation potential (OCP) microtiter wells contained 75 μl plasma and 75 μl OCP buffer, at pH 7.0 with final concentrations of Tris 33 mmol/l, NaCl 65 mmol/l, CaCl2 16.5 mmol/l and tissue factor 0.85 pmol/l. OCP curves were generated from automated absorption measurements at 405 nm taken every minute for 100 min for all samples, an extension to the original 60 minute protocol to ensure the fibrinolysis curves in all samples had returned to zero (baseline) to enable calculation of OHP assay parameters. OHP curves were generated using a similar method, except that the added buffer also contained rt-PA to give a final concentration of 300 ng/ml. Values for OCP and OHP represent the area under the relevant fibrin time curve calculated by summation of absorption values (He et al., 1999, 2001). The overall fibrinolysis potential (OFP) value was calculated by (OCP − OHP) / OCP × 100% and represents the area under the fibrinolytic portion of the curve as a percentage of the total OCP value. Additional data derived from the fibrin time curve included maximum optical density (Max OD), maximum slope (Max slope) and delay in onset of fibrin generation (Delay). Because all assays were performed in duplicate, Max OD is the mean of the maximum OD reached in the two OCP curves. The slope was calculated progressively for each OD reading on the OCP curve, using a minimum of three time points. The greatest increase in OD for these points represents the Max slope. Delay was defined as the time intercept between the line of maximum slope on the OCP curve and the line of baseline absorbance at time zero.

Please cite this article as: Chow, V., et al., Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2014.12.042

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2.3. Biochemical analyses Peripheral venous blood sample biochemical analyses included fasting plasma lipid profile, electrolytes, and liver and thyroid function tests. Measurements of systemic inflammation included full blood count and its differentials (neutrophil, lymphocyte and eosinophil counts) and high-sensitivity C-reactive protein (hsCRP). All measurements of hsCRP were performed using an immuno-turbidimetric method, on an autoanalyser (IMMAGE CRPH; Beckman Coulter, Villepinte, France). Glycosylated haemoglobin (HbA1c) was measured by high-pressure liquid chromatography (BioRad, Hercules, CA). The standard clotting assays prothrombin time, activated partial thromboplastin time, D-dimer and Clauss fibrinogen were performed on an automated coagulation analyser (STA-R, Diagnostica Stago). Reagents were from Dade-Behring Diagnostics (NSW, Australia) and Diagnostica Stago. Platelet count was obtained by optical and impedance methods (Abbott Diagnostics CELL-DYN Sapphire). Plasminogen-activator-inhibitor-1 (PAI-1) (TriniLIZE PAI-1 Antigen, Trinity Biotech, Bray, Ireland) antigen levels were measured by ELISA in accordance with the manufacturer's instructions (samples were diluted 2 in 3 with sample buffer solution). 2.4. Statistical analyses Data were summarized as frequencies and percentages for categorical variables. Continuous variables were presented as mean ± standard deviation. Comparison between two groups was based on unpaired t test (parametric distribution) or Mann–Whitney test (non-parametric distribution) for continuous variables and χ2 tests or the Fisher exact test for dichotomous variables. A two-tailed p value of b0.05 was used as a cut-off for statistical significance. Amongst patients with schizophrenia, multivariate backward selection linear regression analysis was performed to identify independent associations of the OHP assay parameters (OCP, OHP and OFP). All variables with a univariate p value of b0.10 were included in the multivariate modelling to ensure capture of all independent predictors of the above parameters. Multicollinearity between variables was tested using Variance Inflation Factor calculation. Statistical analysis was performed using GraphPad Prism 6.01 (GraphPad Software, San Diego, CA) and SPSS (Version 16.0, SPSS Inc., Chicago, IL). Based on previous published literature and in house data of OHP assay parameters and standard deviation values (Curnow et al., 2007; Edelman et al., 2013), a sample size of 30 subjects in each group could detect significance difference in OHP assay parameters between patients with schizophrenia and healthy controls with a two-sided significance level of 0.05 and statistical power of at least 80%. 3. Results 3.1. Baseline characteristics A total of 120 subjects participated in the study, 90 patients with schizophrenia and 30 healthy controls matched for age, gender and body mass index (BMI). Table 1 summarizes the clinical characteristics of the subjects. For patients with schizophrenia, the mean duration of antipsychotic treatment was 15.9 ± 9.7 years, with the majority receiving clozapine treatment. They had higher rates of smoking, family history of mental illness and hypercholesterolemia. No subjects had a history of PE or DVT prior to recruitment. Following the initial recruitment, one patient with schizophrenia was subsequently diagnosed with DVT and PE, and there were two subsequent sudden deaths in the schizophrenia group. One of the deaths was presumed to be due to drug overdose whilst the other was due to an acute myocardial infarction (an incidental unilateral right lower limb DVT was found on autopsy).

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Table 1 Baseline characteristics.

Age (years) Gender Male Schizophrenia Duration of illness (years) Family history of mental illness Clozapine therapy Body mass index (kg/m2) Comorbidities Alcohol excess Atrial fibrillation Heart failure Previous history of heart failure NYHA class N 1 Stroke Thyroid dysfunction Risk factors for ischaemic heart disease Diabetes Hypercholesterolemia Statin therapy Hypertension Smoking Cardiac observations Systolic blood pressure (mm Hg) Diastolic blood pressure (mm Hg) Resting heart rate (bpm)

Patients with schizophrenia (n = 90)

Controls (n = 30)

40 ± 13

43 ± 12

61 (68)

17 (57)

15.9 ± 9.7 18 (20) 68 (76) 29.1 ± 6.5

– 0 – 27.6 ± 4.4

9 (10) 0

0 0

1 (1) 1 (1) 1 (1) 1 (1)

0 0 0 0

21 (24) 25 (28) 19 (21) 11 (12) 35 (39)

3 (10) 0 0 5 (17) 2 (7)

124 ± 11 77 ± 9 88 ± 13

119 ± 11 73 ± 8 70 ± 7

Categorical variables are presented as numbers (%). Continuous values are presented as mean ± SD. bpm, beats per minute; NYHA, New York Heart Association functional class.

3.2. Biochemical and OHP assay parameters Patients with schizophrenia had higher levels of inflammatory markers including hsCRP (3.7 ± 5.3 vs 0.9 ± 0.8 mg/l, p b 0.001) and neutrophil-to-lymphocyte ratio (NLR) (2.5 ± 1.4 vs 1.7 ± 0.8, p = 0.03) compared to healthy controls. Triglyceride levels were significantly higher (2.0 ± 1.4 vs 1.2 ± 0.6 mmol/l, p = 0.02) and HDL levels were significantly lower (1.2 ± 0.4 vs 1.4 ± 0.3 mmol/l, p = 0.01) in patients with schizophrenia. Whereas D-dimer, fibrinogen and platelet count did not differ between the two groups, the OCP (54.0 ± 12.6 vs 45.9 ± 9.1, p = 0.002) and OHP (12.6 ± 5.8 vs 7.2 ± 3.7, p b 0.001) were both significantly higher, and OFP (76.6 ± 9.8% vs 84.9 ± 6.4%, p b 0.001) significantly lower, in patients with schizophrenia, indicating both a hypercoagulable and hypofibrinolytic state, compared to the controls. There were no observable differences in Max OD and Max slope in the two groups. The delay in the onset of fibrin generation was significantly shorter in healthy controls compared to patients with schizophrenia (13.5 ± 3.4 vs 16.0 ± 5.3 min, p = 0.02) (Fig. 1). The reduced OFP prompted investigation of PAI-1 levels in these patients. PAI-1 levels were significantly higher in patients with schizophrenia than in the control group (29.0 ± 12.1 vs 21.8 ± 9.4, p = 0.006) (Table 2). Although D -dimer, fibrinogen and platelet count did not differ significantly between controls and patients with schizophrenia, their levels did correlate with OHP assay values in the patients with schizophrenia (Tables 3 and 4). In patients with schizophrenia, OCP values demonstrated significant univariate associations with raised D -dimer, fibrinogen, hsCRP, NLR and triglyceride levels. In multivariate analysis, elevated fibrinogen (β = 0.39, p = 0.001) and hsCRP (β = 0.26, p = 0.02) levels were independent predictors of OCP level in these patients. Elevated OHP and decreased OFP levels indicate a hypofibrinolytic state. Significant univariate associations with higher OHP included higher BMI, fibrinogen, D-dimer, PAI-1, hsCRP levels and raised NLR. In multivariate analysis, raised fibrinogen (β = 0.43, p b 0.001), platelet

Please cite this article as: Chow, V., et al., Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2014.12.042

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Fig. 1. OHP assay parameters between patients with schizophrenia and healthy controls. A) Overall coagulation potential (OCP); B) overall haemostatic potential (OHP); C) overall fibrinolytic potential (OFP); D) maximum optical density (Max OD); E) Delay and F) Max slope. G) Reference sample of the OCP and OHP in a patient with schizophrenia and a healthy control.

count (β = 0.25, p = 0.01) and PAI-1 levels (β = 0.23, p = 0.02) remained as significant independent predictors of a raised OHP. Significant univariate associations with lower OFP included raised white cell count, BMI, fibrinogen, PAI-1, total cholesterol and triglyceride levels and lower high-density lipoprotein (HDL) levels. In multivariate analysis, the independent predictors of a reduced OFP state included raised triglyceride (β = − 0.35, p = 0.001), PAI-1 (β = − 0.29, p = 0.002) and fibrinogen (β = −0.23, p = 0.03) levels. We investigated the influence of antipsychotic medications on the coagulation status of patients with schizophrenia, specifically investigating whether clozapine use affected these parameters given previously reported increased VTE risks in these patients (Walker et al., 1997). Patients with schizophrenia receiving clozapine or non-clozapine antipsychotic medications were significantly more hypercoagulable (higher OHP, p = 0.006) and had impaired fibrinolysis (higher OCP, p b 0.001 and lower OFP, p = 0.002) than did healthy controls

(Supplementary Fig. 1). However, there were no significant differences in OHP, OCP and OFP values between patients receiving clozapine or non-clozapine medications. There were 36 patients receiving adjunct therapy in additional to neuroleptic drugs and these included: sertraline (8), sodium valproate (6), citalopram (5), escitalopram (4), fluoxetine (4), lithium (3), lamotrigine (3), venlafaxine (2) and mirtazepine (1). On exploratory analysis, we found no associations between adjunct usage and OHP assay parameters (OCP: p = 0.55, OHP: p = 0.26, OFP: p = 0.21). 4. Discussion We have identified increased overall coagulation potential and impaired overall fibrinolysis potential in patients with schizophrenia receiving long-term antipsychotics. These haemostatic abnormalities were independently associated with abnormalities in PAI-1, fibrinogen,

Please cite this article as: Chow, V., et al., Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2014.12.042

V. Chow et al. / Schizophrenia Research xxx (2015) xxx–xxx

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Table 2 Biochemical parameters. Patients with schizophrenia (n = 90) Biochemical parameters Haemoglobin (g/l) White cell count (×109/l) Neutrophil count (×109/l) Neutrophil:lymphocyte ratio Eosinophil count (×109/l) hsCRP (mg/l) HbA1c (%) Total cholesterol (mmol/l) Triglycerides (mmol/l) HDL (mmol/l) LDL (mmol/l) Platelet count (×109/l) Fibrinogen (g/l) D-dimer (mg/l) PAI-1 (ng/ml)

143 ± 14 7.8 ± 2.5 4.9 ± 2.1 2.5 ± 1.4 0.17 ± 0.1 3.7 ± 5.3 5.9 ± 1.1 5.0 ± 1.1 2.0 ± 1.4 1.2 ± 0.4 3.0 ± 1.0 261 ± 75 3.4 ± 0.7 0.19 ± 0.11 29.0 ± 12.1

OHP assay OHP OCP OFP (%) Max OD (units) Max slope (units) Delay (min)

12.6 ± 5.8 54.0 ± 12.6 76.6 ± 9.8 0.7 ± 0.1 222.3 ± 58.9 16.0 ± 5.3

Controls (n = 30)

p value

148 ± 10 6.5 ± 1.5 3.6 ± 1.0 1.7 ± 0.8 0.17 ± 0.1 0.9 ± 0.8 5.6 ± 0.9 4.9 ± 0.7 1.2 ± 0.6 1.4 ± 0.3 3.0 ± 0.7 249 ± 53 3.1 ± 0.6 0.22 ± 0.28 21.8 ± 9.4

0.19 0.004⁎ b0.001⁎ 0.03⁎ 0.82 b0.001⁎

7.2 ± 3.7 45.9 ± 9.1 84.9 ± 6.4 0.7 ± 0.2 227 ± 43.5 13.5 ± 3.4

0.27 0.63 0.02⁎ 0.01⁎ 0.95 0.48 0.35 0.71 0.006⁎

b0.001⁎ 0.002⁎ b0.001⁎ 0.52 0.69 0.02⁎

Intra-assay CV (%)

Inter-assay CV (%)

1.73 7.35 2.61 0.81 7.37 3.37

3.78 10.43 1.90 4.28 13.36 8.18

Continuous values are presented as mean ± SD. hsCRP, high sensitivity C-reactive protein; HDL, high density lipoprotein; LDL, low density lipoprotein; HbA1c, glycosylated haemoglobin, PAI-1, plasminogen-activator-inhibitor-1; OHP, overall haemostatic potential; OCP, overall coagulation potential; OFP, overall fibrinolysis potential; OD, optical density; CV, coefficient of variation. ⁎ p b 0.05.

or venous thromboembolism, are often not detected by the traditional panel of tests as part of thrombophilia screening (including deficiencies of antithrombin, proteins C and S, factor V Leiden and prothrombin G20210A mutations). A negative thrombophilia test may lead to false assurance as thrombophilia can only identify approximately 50% of all patients presenting with venous thrombosis by utilising the above tests (Whiteman and Hassouna, 2000; Middeldorp and van Hylckama Vlieg, 2008; Middeldorp, 2011b). The OHP assay is a simple and inexpensive global coagulation assay that detects both the dynamic coagulation and fibrinolytic potential of plasma samples. It has been shown to be useful in identifying

platelet count, inflammatory markers and lipoprotein levels suggesting these as contributing factors to the risk of VTE in these patients. Routine coagulation assays are based on the traditional cascade model of coagulation and detect hypercoagulable states due to inherited deficient or abnormal coagulation factors and acquired inhibitors. Unselected screening for inherited thrombophilic states in asymptomatic patients is not recommended due to the low frequency, low penetrance of symptomatic VTE amongst carriers of the most common thrombophilic conditions and the high cost associated with testing (Machin, 2003; Middeldorp, 2011a). Furthermore, hypercoagulable states, which are defined as those with the potential to develop arterial

Table 3 Correlation analysis in patients with schizophrenia (n = 90). OCP Correlation coefficient Clinical variables Age Body mass index Diabetes Hypercholesterolemia Smoking Clozapine treatment Laboratory markers Platelet D-dimer

Fibrinogen PAI-1 hsCRP White cell count Neutro:lymph ratio Cholesterol HDL Triglyceride

0.08 0.20 −0.07 −0.07 −0.03 0.07

OHP p value 0.45 0.07 0.51 0.53 0.77 0.56

Correlation coefficient

OFP p value

p value

−0.02 0.33 0.02 0.09 0.04 −0.05

0.87 0.002⁎ 0.85 0.41 0.74 0.64

0.02 −0.22 −0.11 −0.19 −0.07 0.05

0.90 0.04⁎ 0.34 0.08 0.51 0.63

−0.26 −0.03

0.02⁎ 0.82 0.04⁎

0.13 0.35

0.23 0.001⁎

0.31 0.23

0.004⁎ 0.04⁎

0.61 −0.02 0.49 0.25 0.39 −0.19 0.03 0.34

b0.001⁎ 0.83 b0.001⁎ 0.02⁎ b0.001⁎

0.50 0.30 0.35 0.41 0.23 0.17 −0.17 0.12

b0.001⁎ 0.008⁎ 0.001⁎ b0.001⁎ 0.03⁎

0.11 0.81 0.002⁎

Correlation coefficient

0.11 0.10 0.28

−0.22 −0.31 −0.10 −0.33 −0.07 −0.41 0.23 −0.41

0.005⁎ 0.35 0.002⁎

0.53 b0.001⁎ 0.03⁎ b0.001⁎

PAI-1, plasminogen-activator-inhibitor-1; hsCRP, high sensitivity C-reactive protein; HDL, high density lipoprotein; OCP, overall coagulation potential; OHP, overall haemostatic potential; OFP, overall fibrinolysis potential. Pearson's and Spearman's correlations were performed for parametric and non-parametric variables respectively. Point biserial correlation was applied to dichotomous and continuous variables. ⁎ p b 0.05.

Please cite this article as: Chow, V., et al., Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2014.12.042

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V. Chow et al. / Schizophrenia Research xxx (2015) xxx–xxx

Table 4 Standardized coefficient β

p value

Multivariate predictors of increased OCP in patients with schizophrenia (n = 90) Fibrinogen 0.39 0.001* hsCRP 0.26 0.02* Backward selection regression model using a p value cut-off of b0.1, R2 = 0.36. hsCRP, high sensitivity C-reactive protein. *p b 0.05. Multivariate predictors of increased OHP in patients with schizophrenia (n = 90) Fibrinogen 0.43 b0.001* Platelet count 0.25 0.01* PAI-1 0.23 0.02* Backward selection regression model using a p value cut-off of b0.1, R2 = 0.33. PAI-1, plasminogen-activator-inhibitor-1. *p b 0.05. Multivariate predictors of reduced OFP in patients with schizophrenia (n = 90) Triglycerides 0.35 0.001* PAI-1 0.29 0.002* Fibrinogen 0.23 0.03* WCC 0.19 0.07 Backward selection regression model using a p value cut-off of b0.1, R2 = 0.35. PAI-1, plasminogen-activator-inhibitor-1; WCC, white cell count. *p b 0.05.

hypercoagulable states in a number of patient groups (Vedin et al., 2005; Curnow et al., 2007; Reddel et al., 2013). The generation of a fibrin time curve from serial spectrophotometric measurements in an ex vivo environment represents the balance between fibrin generation and lysis. This underlying principle of the OHP assay determines whether the hypercoagulable state is due to increased fibrin generation, reduced fibrinolysis or a combination of these. Thus, the OHP assay is expected to be dependent on levels of factors such as plasma fibrinogen (promotion of coagulation) and PAI-1 inhibitor (inhibition of fibrinolysis). In our patients with schizophrenia, plasma fibrinogen was an independent predictor of raised OCP, OHP and OFP whilst PAI-1 was an independent predictor of OFP and OHP, even after adjusting for BMI and other clinical factors. Our OHP assay results indicate that patients with schizophrenia have a hypercoagulable state due to a combination of increased fibrin generation (higher OCP, p = 0.002) and reduced fibrinolysis (higher OHP and lower OFP, both p b 0.001). The underlying biological mechanisms by which patients with schizophrenia receiving antipsychotic medications develop VTE are complex and likely multifactorial. Several mechanisms have been suggested, including enhanced platelet aggregation and adhesion (Boullin et al., 1978; Axelsson et al., 2007), the development of antiphospholipid antibodies (Davis et al., 1994) and raised homocysteine levels (Hu et al., 2013). The increased risk may also be exacerbated by antipsychotic-induced sedation resulting in venous stasis. Whilst obesity is an independent risk factor for VTE (Torbicki et al., 2008) and is frequent in patients with schizophrenia, in particular those receiving clozapine (Fitzsimons et al., 2005), previous studies have confirmed that the increased risk of VTE amongst patients with schizophrenia persists even after controlling for BMI and other clinical factors (Zornberg and Jick, 2000; Parkin et al., 2003). Furthermore, the schizophrenic illness in itself has been shown to have a propensity for increasing the risk of thrombogenesis with raised markers for thrombosis (D-dimer), thrombocyte activation (soluble P-selectin and L-selectin) and platelet dysfunction (increased platelet expression of integrins) reported in antipsychotic drug-naive patients with schizophrenia (Walsh et al., 2002; Iwata et al., 2007; Masopust et al., 2011). Our study cannot draw conclusions regarding a causal role for antipsychotic medications in mediating the altered coagulation status of these patients. All our patients had been stabilised on their current antipsychotic regime prior to enrolment in this study and the effect of medication per se in our cohort is unknown. Amongst the patients with schizophrenia, we did not find any association between the type of medication used and OHP parameters. Larger patient numbers and the evaluation of patients before and after starting antipsychotic

medications will be required to establish differences between specific antipsychotic medications. The metabolic syndrome, which is associated with elevated inflammatory markers and plasma triglycerides, is an independent risk factor for VTE (Ageno et al., 2006; Wang et al., 2010). Whether raised HDL is protective against VTE remains unclear. Some cohort studies have demonstrated no clear association between HDL and risk of VTE, whilst others indicated that elevated HDL may increase risk of unprovoked VTE in women (Chamberlain et al., 2008; Braekkan et al., 2009; Everett et al., 2009). A recent meta-analysis concluded that HDL was protective against VTE (Ageno et al., 2008). Reduced HDL was identified in patients presenting with massive PE (Wang et al., 2010) and was associated with VTE recurrence (Eichinger et al., 2007). Possible HDL-related protective mechanisms include reduced thrombin generation via promotion of the protein C pathway (Griffin et al., 1999), enhanced endothelial nitric oxide synthase activity and reduced leukocyte adhesion to endothelium (Mineo et al., 2006). In our patients with schizophrenia, raised hsCRP and triglycerides were independent predictors of impaired OCP and OHP supporting a role for inflammation and the metabolic syndrome. The independent associations identified on multivariate analysis highlight the potential for interaction between factors in determining the overall hypercoagulable state in patients with schizophrenia. The association between an inflammatory state (raised hsCRP) with hypercoagulability and the association between raised triglyceride levels with hypofibrinolysis are interesting. Hypofibrinolysis has been shown to be a risk factor for a first venous and/or arterial thrombotic event in three large case–control studies (Lisman et al., 2005; Guimaraes et al., 2009; Meltzer et al., 2009) and was an independent predictor for VTE in another study (Cellai et al., 2013). Furthermore, the combination of hypercoagulability and hypofibrinolysis appears to synergistically increase the risk for VTE (Meltzer et al., 2008). Potential therapeutic intervention with statin and/or fibrate therapy for these modifiable risk factors may reduce the overall hypercoagulable state and incidence of VTE in patients with schizophrenia. In addition to modifying the lipid profile, statin therapy has been proposed to have multiple pleiotropic effects (Waldman and Kritharides, 2003) with significant reductions in the occurrence of symptomatic VTE (hazard ratio 0.57, p = 0.007) and hsCRP as reported in the JUPITER trial of healthy older adults treated with rosuvastatin (Glynn et al., 2009). These findings were reaffirmed in recent metaanalyses showing significant reduction in VTE events amongst patients treated with statin therapy (Agarwal et al., 2010; Squizzato et al., 2010; Li et al., 2011; Pai et al., 2011; Rodriguez et al., 2012). Statins may increase nitric oxide bioavailability, regulate angiogenesis, reduce the inflammatory response and down-regulate the blood coagulation cascade (Undas et al., 2005). In addition, statins have been shown to decrease platelet aggregation, tissue factor (Rosenson and Tangney, 1998; Undas et al., 2002), PAI-1 (Rosenson and Tangney, 1998; Nishino et al., 2008), interleukin-6 and interleukin-8 (Rezaie-Majd et al., 2002) and hsCRP (Albert et al., 2001; Glynn et al., 2009) levels, and increase tPA and thrombomodulin expression (Rosenson and Tangney, 1998; Perez and Bartholomew, 2010). Given these prior results, future studies should explore the effects of statin therapy on OHP assay parameters in patients with schizophrenia. We note several limitations to our study. First, the standard OHP assay uses platelet-poor plasma and may therefore underestimate the role of platelets in global assays of coagulation. Second, our patients with schizophrenia had more cardiovascular risk factors than controls and this may contribute to their observed hypercoagulable state, making the drawing of conclusions regarding thrombotic risk due to psychosis itself less straightforward. However, this is clinically quite important as the thrombosis risk in patients with schizophrenia is likely contributed to many factors including co-existing cardiovascular risk factors.

Please cite this article as: Chow, V., et al., Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2014.12.042

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In conclusion, we report for the first time that a hypercoagulable and hypofibrinolytic state is present in patients with schizophrenia on longterm antipsychotic medications. These data may help our understanding of the mechanisms underlying the increased risk for VTE in this patient population. Supplementary data to this article can be found online at http://dx. doi.org/10.1016/j.schres.2014.12.042. Role of funding source This study is supported by the Australian Postgraduate Awards Scholarship from the University of Sydney [Postgraduate Medical Scholarship to V Chow] and a Program Grant from the Australian Government National Health and Medical Research Council (L Kritharides) Grant No: 1037903. The funders had no role in the study design, data collection, data analysis, data interpretation, writing of the report, or decision to submit the results. Contributors V. Chow, C. Reddel, G. Pennings, A. C. C. Ng, J. Curnow and L. Kritharides designed the study, analysed and interpreted the data. V. Chow, A. C. C. Ng and L. Kritharides drafted the manuscript. T. Yeoh, E. Scott, and T. Pasqualon contributed to the critical revision of the manuscript for important intellectual content. V. Chow and L. Kritharides are guarantors. Conflict of interest J. Curnow is a consultant haematologist for Clozapine Patient Monitoring Service (Norvatis), Australia. All other authors have no conflict of interest. Acknowledgements None.

References Agarwal, V., Phung, O.J., Tongbram, V., Bhardwaj, A., Coleman, C.I., 2010. Statin use and the prevention of venous thromboembolism: a meta-analysis. Int. J. Clin. Pract. 64 (10), 1375–1383. Ageno, W., Squizzato, A., Garcia, D., Imberti, D., 2006. Epidemiology and risk factors of venous thromboembolism. Semin. Thromb. Hemost. 36, 772–779 (32(7), 651–658). Ageno, W., Becattini, C., Brighton, T., Selby, R., Kamphuisen, P.W., 2008. Cardiovascular risk factors and venous thromboembolism: a meta-analysis. Circulation 117 (1), 93–102. Albert, M.A., Danielson, E., Rifai, N., Ridker, P.M., 2001. Effect of statin therapy on Creactive protein levels: the pravastatin inflammation/CRP evaluation (PRINCE): a randomized trial and cohort study. JAMA 286 (1), 64–70. American Psychiatric Association, 1994. Diagnostic and Statistical Manual of Mental Disorders. 4th edition (Washington, DC). Anderson Jr., F.A., Spencer, F.A., 2003. Risk factors for venous thromboembolism. Circulation 107 (23 Suppl. 1), I9–I16. Authors/Task Force, Konstantinides, M., Torbicki, S.V., Agnelli, A., Danchin, G., Fitzmaurice, N., Galie, D., Gibbs, N., Huisman, J.S., Humbert, M.V., Kucher, M., Lang, N., Lankeit, I., Lekakis, M., Maack, J., Mayer, C., Meneveau, E., Perrier, N., Pruszczyk, A., Rasmussen, P., Schindler, L.H., Svitil, T.H., Vonk Noordegraaf, P., Zamorano, A., Zompatori, J.L., Authors/Task Force, 2014. 2014 ESC guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC) Endorsed by the European Respiratory Society (ERS). Eur. Heart J. 35 (43), 3033–3069. Axelsson, S., Hagg, S., Eriksson, A.C., Lindahl, T.L., Whiss, P.A., 2007. In vitro effects of antipsychotics on human platelet adhesion and aggregation and plasma coagulation. Clin. Exp. Pharmacol. Physiol. 34 (8), 775–780 (34(8), 775–780). Baglin, T., Gray, E., Greaves, M., Hunt, B.J., Keeling, D., Machin, S., Mackie, I., Makris, M., Nokes, T., Perry, D., Tait, R.C., Walker, I., Watson, H., 2010. Clinical guidelines for testing for heritable thrombophilia. Br. J. Haematol. 149 (2), 209–220. Bank, I., van de Poel, M.H., Coppens, M., Hamulyak, K., Prins, M.H., van der Meer, J., Veeger, N.J., Buller, H.R., Middeldorp, S., 2007. Absolute annual incidences of first events of venous thromboembolism and arterial vascular events in individuals with elevated FVIII:c. A prospective family cohort study. Thromb. Haemost. 98 (5), 1040–1044. Boullin, D.J., Know, J.M., Peters, J.R., Orr, M.W., Gelder, M.G., Grahame-Smith, D.G., 1978. Platelet aggregation and chlorpromazine therapy. Br. J. Clin. Pharmacol. 6 (6), 538–540. Braekkan, S.K., Borch, K.H., Mathiesen, E.B., Njolstad, I., Hansen, J.B., 2009. HDL-cholesterol and future risk of venous thromboembolism: the Tromso Study. J. Thromb. Haemost. 7 (8), 1428–1430. Bucciarelli, P., Passamonti, S.M., Biguzzi, E., Gianniello, F., Franchi, F., Mannucci, P.M., Martinelli, I., 2012. Low borderline plasma levels of antithrombin, protein C and protein S are risk factors for venous thromboembolism. J. Thromb. Haemost. 10 (9), 1783–1791. Carrizo, E., Fernandez, V., Quintero, J., Connell, L., Rodriguez, Z., Mosquera, M., Acosta, A., Baptista, T., 2008. Coagulation and inflammation markers during atypical or typical antipsychotic treatment in schizophrenia patients and drug-free first-degree relatives. Schizophr. Res. 103 (1–3), 83–93.

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Cellai, A.P., Lami, D., Antonucci, E., Fiorillo, C., Becatti, M., Olimpieri, B., Bani, D., Grifoni, E., Cenci, C., Marcucci, R., Mannini, L., Poli, D., Abbate, R., Prisco, D., 2013. Fibrinolytic inhibitors and fibrin characteristics determine a hypofibrinolytic state in patients with pulmonary embolism. Thromb. Haemost. 109 (3), 565–567. Cesari, M., Pahor, M., Incalzi, R.A., 2010. Plasminogen activator inhibitor-1 (PAI-1): a key factor linking fibrinolysis and age-related subclinical and clinical conditions. Cardiovasc. Ther. 28 (5), e72–e91. Chamberlain, A.M., Folsom, A.R., Heckbert, S.R., Rosamond, W.D., Cushman, M., 2008. High-density lipoprotein cholesterol and venous thromboembolism in the Longitudinal Investigation of Thromboembolism Etiology (LITE). Blood 112 (7), 2675–2680. Curnow, J.L., Morel-Kopp, M.C., Roddie, C., Aboud, M., Ward, C.M., 2007. Reduced fibrinolysis and increased fibrin generation can be detected in hypercoagulable patients using the overall hemostatic potential assay. J. Thromb. Haemost. 5 (3), 528–534. Davis, S., Kern, H.B., Asokan, R., 1994. Antiphospholipid antibodies associated with clozapine treatment. Am. J. Hematol. 46 (2), 166–167 (46(2), 166–167). Edelman, J.J., Reddel, C.J., Kritharides, L., Bannon, P.G., Fraser, J.F., Curnow, J.L., Vallely, M.P., 2013. Natural history of hypercoagulability in patients undergoing coronary revascularization and effect of preoperative myocardial infarction. J. Thorac. Cardiovasc. Surg. 148 (2), 536–543. Eichinger, S., Pecheniuk, N.M., Hron, G., Deguchi, H., Schemper, M., Kyrle, P.A., Griffin, J.H., 2007. High-density lipoprotein and the risk of recurrent venous thromboembolism. Circulation 115 (12), 1609–1614. Everett, B.M., Glynn, R.J., Buring, J.E., Ridker, P.M., 2009. Lipid biomarkers, hormone therapy and the risk of venous thromboembolism in women. J. Thromb. Haemost. 7 (4), 588–596. Fitzsimons, J., Berk, M., Lambert, T., Bourin, M., Dodd, S., 2005. A review of clozapine safety. Expert Opin. Drug Saf. 4 (4), 731–744. Furie, B., Furie, B.C., 2008. Mechanisms of thrombus formation. N. Engl. J. Med. 359 (9), 938–949. Glynn, R.J., Danielson, E., Fonseca, F.A., Genest, J., Gotto Jr., A.M., Kastelein, J.J., Koenig, W., Libby, P., Lorenzatti, A.J., MacFadyen, J.G., Nordestgaard, B.G., Shepherd, J., Willerson, J.T., Ridker, P.M., 2009. A randomized trial of rosuvastatin in the prevention of venous thromboembolism. N. Engl. J. Med. 360 (18), 1851–1861. Griffin, J.H., Kojima, K., Banka, C.L., Curtiss, L.K., Fernandez, J.A., 1999. High-density lipoprotein enhancement of anticoagulant activities of plasma protein S and activated protein C. J. Clin. Invest. 103 (2), 219–227. Guimaraes, A.H., de Bruijne, E.L., Lisman, T., Dippel, D.W., Deckers, J.W., Poldermans, D., Rijken, D.C., Leebeek, F.W., 2009. Hypofibrinolysis is a risk factor for arterial thrombosis at young age. Br. J. Haematol. 145 (1), 115–120. Hagg, S., Jonsson, A.K., Spigset, O., 2009. Risk of venous thromboembolism due to antipsychotic drug therapy. Expert Opin. Drug Saf. 8 (5), 537–547. He, S., Bremme, K., Blomback, M., 1999. A laboratory method for determination of overall haemostatic potential in plasma. I. Method design and preliminary results. Thromb. Res. 96 (2), 145–156. He, S., Antovic, A., Blomback, M., 2001. A simple and rapid laboratory method for determination of haemostasis potential in plasma. II. Modifications for use in routine laboratories and research work. Thromb. Res. 103 (5), 355–361. Hu, Q., Zhang, C., Zhu, S., 2013. Fatal multisystem venous thrombosis associated with clozapine. J. Clin. Psychopharmacol. 33 (2), 256–258. Iwata, Y., Suzuki, K., Nakamura, K., Matsuzaki, H., Sekine, Y., Tsuchiya, K.J., Sugihara, G., Kawai, M., Minabe, Y., Takei, N., Mori, N., 2007. Increased levels of serum soluble L-selectin in unmedicated patients with schizophrenia. Schizophr. Res. 89 (1–3), 154–160. Jenkins, P.V., Rawley, O., Smith, O.P., O'Donnell, J.S., 2012a. Elevated factor VIII levels and risk of venous thrombosis. Br. J. Haematol. 157 (6), 653–663. Jenkins, P.V., Rawley, O., Smith, O.P., O'Donnell, J.S., 2012b. Elevated factor VIII levels and risk of venous thrombosis. Br. J. Haematol. 157 (6), 653–663 (157(6), 653–663). Jennings, I., Kitchen, S., Woods, T.A., Preston, F.E., 2005. Multilaboratory testing in thrombophilia through the United Kingdom National External Quality Assessment Scheme (Blood Coagulation) Quality Assurance Program. Semin. Thromb. Hemost. 31 (1), 66–72. Koster, T., Blann, A.D., Briet, E., Vandenbroucke, J.P., Rosendaal, F.R., 1995a. Role of clotting factor VIII in effect of von Willebrand factor on occurrence of deep-vein thrombosis. Lancet 345 (8943), 152–155. Koster, T., Rosendaal, F.R., Briet, E., van der Meer, F.J., Colly, L.P., Trienekens, P.H., Poort, S.R., Reitsma, P.H., Vandenbroucke, J.P., 1995b. Protein C deficiency in a controlled series of unselected outpatients: an infrequent but clear risk factor for venous thrombosis (Leiden Thrombophilia Study). Blood 85 (10), 2756–2761. Li, L., Sun, T., Zhang, P., Tian, J., Yang, K., 2011. Statins for primary prevention of venous thromboembolism. Cochrane Database Syst. Rev. 12, (CD008203). Lisman, T., de Groot, P.G., Meijers, J.C., Rosendaal, F.R., 2005. Reduced plasma fibrinolytic potential is a risk factor for venous thrombosis. Blood 105 (3), 1102–1105. Machin, S.J., 2003. Pros and cons of thrombophilia testing: cons. J. Thromb. Haemost. 1 (3), 412–413. Mahmoodi, B.K., Brouwer, J.L., Ten Kate, M.K., Lijfering, W.M., Veeger, N.J., Mulder, A.B., Kluin-Nelemans, H.C., Van Der Meer, J., 2010. A prospective cohort study on the absolute risks of venous thromboembolism and predictive value of screening asymptomatic relatives of patients with hereditary deficiencies of protein S, protein C or antithrombin. J. Thromb. Haemost. 8 (6), 1193–1200. Masopust, J., Maly, R., Andrys, C., Valis, M., Bazant, J., Hosak, L., 2011. Markers of thrombogenesis are activated in unmedicated patients with acute psychosis: a matched case control study. BMC Psychiatry 11, 2. Meltzer, M.E., Lisman, T., Doggen, C.J., de Groot, P.G., Rosendaal, F.R., 2008. Synergistic effects of hypofibrinolysis and genetic and acquired risk factors on the risk of a first venous thrombosis. PLoS Med. 5 (5), e97.

Please cite this article as: Chow, V., et al., Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2014.12.042

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V. Chow et al. / Schizophrenia Research xxx (2015) xxx–xxx

Meltzer, M.E., Doggen, C.J., de Groot, P.G., Rosendaal, F.R., Lisman, T., 2009. Reduced plasma fibrinolytic capacity as a potential risk factor for a first myocardial infarction in young men. Br. J. Haematol. 145 (1), 121–127. Meltzer, M.E., Lisman, T., de Groot, P.G., Meijers, J.C., le Cessie, S., Doggen, C.J., Rosendaal, F.R., 2010. Venous thrombosis risk associated with plasma hypofibrinolysis is explained by elevated plasma levels of TAFI and PAI-1. Blood 116 (1), 113–121. Middeldorp, S., 2011a. Evidence-based approach to thrombophilia testing. J. Thromb. Thrombolysis 31 (3), 275–281. Middeldorp, S., 2011b. Is thrombophilia testing useful? Hematol. Am. Soc. Hematol. Educ. Prog. 2011, 150–155. Middeldorp, S., van Hylckama Vlieg, A., 2008. Does thrombophilia testing help in the clinical management of patients? Br. J. Haematol. 143 (3), 321–335. Mineo, C., Deguchi, H., Griffin, J.H., Shaul, P.W., 2006. Endothelial and antithrombotic actions of HDL. Circ. Res. 98 (11), 1352–1364. Ng, A.C., Chung, T., Yong, A.S., Wong, H.S., Chow, V., Celermajer, D.S., Kritharides, L., 2011. Long-term cardiovascular and noncardiovascular mortality of 1023 patients with confirmed acute pulmonary embolism. Circ. Cardiovasc. Qual. Outcomes 4 (1), 122–128. Nishino, M., Hoshida, S., Kato, H., Egami, Y., Shutta, R., Yamaguchi, H., Tanaka, K., Tanouchi, J., Hori, M., Yamada, Y., 2008. Preprocedural statin administration can reduce thrombotic reaction after stent implantation. Circ. J. 75 (6), 1472–1475 (72(2), 232–237). Pai, M., Evans, N.S., Shah, S.J., Green, D., Cook, D., Crowther, M.A., 2011. Statins in the prevention of venous thromboembolism: a meta-analysis of observational studies. Thromb. Res. 122 (1), 21–25 (128(5), 422–430). Parker, C., Coupland, C., Hippisley-Cox, J., 2010. Antipsychotic drugs and risk of venous thromboembolism: nested case–control study. BMJ 341, c4245. Parkin, L., Skegg, D.C., Herbison, G.P., Paul, C., 2003. Psychotropic drugs and fatal pulmonary embolism. Pharmacoepidemiol. Drug Saf. 12 (8), 647–652 (12(8), 647– 652). Perez, A., Bartholomew, J.R., 2010. Interpreting the JUPITER trial: statins can prevent VTE, but more study is needed. Cleve. Clin. J. Med. 74 (3), 199–202 (77(3), 191–194). Reddel, C.J., Curnow, J.L., Voitl, J., Rosenov, A., Pennings, G.J., Morel-Kopp, M.-C., Brieger, D.B., 2013. Detection of hypofibrinolysis in stable coronary artery disease using the overall haemostatic potential assay. Thromb. Res. 122 (1), 21–25 (131(5), 457–462). Reitter-Pfoertner, S., Waldhoer, T., Mayerhofer, M., Eigenbauer, E., Ay, C., Mannhalter, C., Kyrle, P.A., Pabinger, I., 2013. The influence of thrombophilia on the long-term survival of patients with a history of venous thromboembolism. Thromb. Haemost. 109 (1), 79–84. Rezaie-Majd, A., Maca, T., Bucek, R.A., Valent, P., Muller, M.R., Husslein, P., Kashanipour, A., Minar, E., Baghestanian, M., 2002. Simvastatin reduces expression of cytokines interleukin-6, interleukin-8, and monocyte chemoattractant protein-1 in circulating monocytes from hypercholesterolemic patients. Arterioscler. Thromb. Vasc. Biol. 22 (7), 1194–1199. Roche-Bayard, P., Rossi, R., Mann, J.M., Cordier, J.F., Delahaye, J.P., 1990. Left pulmonary artery thrombosis in chlorpromazine-induced lupus. Chest 98 (6), 1545. Rodriguez, A.L., Wojcik, B.M., Wrobleski, S.K., Myers Jr., D.D., Wakefield, T.W., Diaz, J.A., 2012. Statins, inflammation and deep vein thrombosis: a systematic review. J. Thromb. Thrombolysis 33 (4), 371–382 (33(4), 371–382).

Rogers, M.A., Levine, D.A., Blumberg, N., Flanders, S.A., Chopra, V., Langa, K.M., 2012. Triggers of hospitalization for venous thromboembolism. Circulation 125 (17), 2092–2099. Rosenson, R.S., Tangney, C.C., 1998. Antiatherothrombotic properties of statins: implications for cardiovascular event reduction. JAMA 279 (20), 1643–1650. Squizzato, A., Galli, M., Romualdi, E., Dentali, F., Kamphuisen, P.W., Guasti, L., Venco, A., Ageno, W., 2010. Statins, fibrates, and venous thromboembolism: a meta-analysis. Eur. Heart J. 31 (10), 1248–1256. Stein, P.D., Kayali, F., Olson, R.E., 2004. Estimated case fatality rate of pulmonary embolism, 1979 to 1998. Am. J. Cardiol. 93 (9), 1197–1199. Torbicki, A., Perrier, A., Konstantinides, S., Agnelli, G., Galie, N., Pruszczyk, P., Bengel, F., Brady, A.J., Ferreira, D., Janssens, U., Klepetko, W., Mayer, E., Remy-Jardin, M., Bassand, J.P., Vahanian, A., Camm, J., De Caterina, R., Dean, V., Dickstein, K., Filippatos, G., Funck-Brentano, C., Hellemans, I., Kristensen, S.D., McGregor, K., Sechtem, U., Silber, S., Tendera, M., Widimsky, P., Zamorano, J.L., Andreotti, F., Ascherman, M., Athanassopoulos, G., De Sutter, J., Fitzmaurice, D., Forster, T., Heras, M., Jondeau, G., Kjeldsen, K., Knuuti, J., Lang, I., Lenzen, M., Lopez-Sendon, J., Nihoyannopoulos, P., Perez Isla, L., Schwehr, U., Torraca, L., Vachiery, J.L., 2008. Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). Eur. Heart J. 29 (18), 2276–2315. Undas, A., Brozek, J., Musial, J., 2002. Anti-inflammatory and antithrombotic effects of statins in the management of coronary artery disease. Clin. Lab. 48 (5–6), 287–296 (48(5-6), 287–296). Undas, A., Brummel-Ziedins, K.E., Mann, K.G., 2005. Statins and blood coagulation. Arterioscler. Thromb. Vasc. Biol. 23 (10), 1881–1888 (25(2), 287–294). Van De Craen, B., Declerck, P.J., Gils, A., 2012. The biochemistry, physiology and pathological roles of PAI-1 and the requirements for PAI-1 inhibition in vivo. Thromb. Res. 122 (1), 21–25 (130(4), 576–585). Varia, I., Krishnan, R.R., Davidson, J., 1983. Deep-vein thrombosis with antipsychotic drugs. Psychosomatics 24 (12), 1097–1098. Vedin, J., Antovic, A., Ericsson, A., Vaage, J., 2005. Hemostasis in off-pump compared to onpump coronary artery bypass grafting: a prospective, randomized study. Ann. Thorac. Surg. 80 (2), 586–593. Waldman, A., Kritharides, L., 2003. The pleiotropic effects of HMG-CoA reductase inhibitors: their role in osteoporosis and dementia. Drugs 63 (2), 139–152. Walker, A.M., Lanza, L.L., Arellano, F., Rothman, K.J., 1997. Mortality in current and former users of clozapine. Epidemiology 8 (6), 671–677. Walsh, M.T., Ryan, M., Hillmann, A., Condren, R., Kenny, D., Dinan, T., Thakore, J.H., 2002. Elevated expression of integrin alpha(IIb) beta(IIIa) in drug-naive, first-episode schizophrenic patients. Biol. Psychiatry 52 (9), 874–879 (52(9), 874–879). Wang, Y., Wang, P., Li, H., 2010. Correlation study of pulmonary embolism and highdensity lipoprotein cholesterol. Clin. Cardiol. 33 (2), 72–76. Whiteman, T., Hassouna, H.I., 2000. Hypercoagulable states. Hematol. Oncol. Clin. North Am. 14 (2), 355–377 (viii). Yukizawa, Y., Inaba, Y., Watanabe, S., Yajima, S., Kobayashi, N., Ishida, T., Iwamoto, N., Choe, H., Saito, T., 2012. Association between venous thromboembolism and plasma levels of both soluble fibrin and plasminogen-activator inhibitor 1 in 170 patients undergoing total hip arthroplasty. Acta Orthop. 83 (1), 14–21 (83(1), 14–21). Zornberg, G.L., Jick, H., 2000. Antipsychotic drug use and risk of first-time idiopathic venous thromboembolism: a case–control study. Lancet 356 (9237), 1219–1223.

Please cite this article as: Chow, V., et al., Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy, Schizophr. Res. (2015), http://dx.doi.org/10.1016/j.schres.2014.12.042