CE: Tripti; JCM-D-14-00249; Total nos of Pages: 6;
JCM-D-14-00249
Original article
Epidemiology and outcomes of peripartum cardiomyopathy in the United States: findings from the Nationwide Inpatient Sample Parasuram Krishnamoorthya, Jalaj Gargb, Chandrasekar Palaniswamyb, Ambarish Pandeyc, Hasan Ahmadb, William H. Frishmanb and Gregg Lanierb Aims Peripartum cardiomyopathy (PPCM) is defined as systolic heart failure within the last month of pregnancy or 5 months after delivery in the absence of any identifiable cause of heart failure. We aimed to investigate the prevalence of PPCM and predictors of in-hospital mortality in patients with PPCM. Methods We analyzed patients with diagnosis of PPCM from the Nationwide Inpatient Sample database using the Ninth Revision of International Classification of Diseases (ICD-9) from 2009 to 2010. We categorized PPCM (n U 4871) into three groups of presentation based on their ICD-9 codes: antepartum (674.53; n U 189), peripartum (674.51, 674.52; n U 887) and postpartum (674.54; n U 3741).
peripartum group. Asians had the highest mortality (8.3%). In multimodel regression analysis, Asians [odds ratio (OR) 9.68, 95% confidence interval (CI) 1.11–83.9, P U 0.03] and length of stay (OR 1.06, 95% CI 1.03–1.10, P < 0.01) were associated with increased mortality, whereas white women were associated with reduced mortality (OR 0.10, 95% CI 0.02–0.59, P U 0.01). Conclusion Although PPCM was prevalent in AfricanAmericans, Asians had higher in-hospital mortality, increased prevalence of preeclampsia and premature labor. Also, mortality rate was significantly higher in the postpartum group. J Cardiovasc Med 2014, 16:000–000
Results PPCM was more common in African-Americans (43.9%) as compared with white (40.8%), Hispanic (8.7%) and Asian (2.7%) women. Hypertensive disorders were classified as pre-existing hypertension (31.6%), gestational hypertension (3.7%), preeclampsia (9.9%), eclampsia (2.4%) and preeclampsia/eclampsia superimposed on hypertension (3.1%). Among different ethnicities, preexisting hypertension (1 : 2.3) and diabetes (1 : 10.4) were more prevalent in African-Americans, whereas preeclampsia (1 : 4.3) and premature labor (1 : 5.4) were more common in Asians. In-hospital mortality rate was 1.8%, with 2.1% in the postpartum and 0.5% in the
Introduction Peripartum cardiomyopathy (PPCM), defined as idiopathic dilated cardiomyopathy associated with pregnancy, is a rare and potentially fatal disease.1,2 The first case was described in the 1930s when it was recognized as a distinct clinical entity.3,4 The reported incidence in the United States varies from 1 : 2289 to 1 : 4000 live births.5 It has a highly unpredictable clinical course, varying from complete recovery6–8 to rapid progression and end-stage heart failure in a few days to weeks.5 The diagnostic criteria are as follows: development of cardiac failure in the last month of pregnancy or within 5 months of delivery; absence of an identifiable cause for the cardiac failure other than pregnancy; absence of recognizable heart disease before the last month of pregnancy and left ventricular systolic dysfunction (LVSD) with left ventricular ejection fraction (LVEF) less than 45% by echocardiography, fractional shortening below 30% or 1558-2027 ß 2014 Italian Federation of Cardiology
Keywords: epidemiology, mortality, outcomes, peripartum cardiomyopathy, preeclampsia, risk factors a
Department of Medicine, Englewood Hospital and Medical Center, New Jersey, Department of Internal Medicine, Division of Cardiology, Westchester Medical Center, New York Medical College, New York and cDepartment of Medicine, Division of Cardiology, University of Texas, Texas, USA
b
Correspondence to Parasuram Krishnamoorthy, MD, Department of Internal Medicine, Englewood Hospital and Medical Center, Englewood, NJ 07631, USA Tel: +1 732 501 5100; fax: +1 201 894 0839; e-mail: [email protected] Received 19 April 2014 Revised 26 June 2014 Accepted 3 September 2014
both.1,5,9 However, Elkayam et al.10 and Sliwa et al.11 demonstrated that patients could present with similar symptoms even before the last gestational month, with no significant difference in maternal outcome, and hence could represent a continuum in the spectrum of the same disease. The cause remains unclear and appears to be multifactorial with the Afro-American race being the strongest risk factor.8 Other risk factors identified are twin gestation, multiparity,12 advanced maternal age13 and preeclampsia.14 Other pathological processes including myocarditis, autoimmunity15,16 and oxidative stress17 have also been linked to PPCM. Blauwet et al.18 and Goland et al.19 reported predictors of clinical outcomes in small cohorts of patients with PPCM. However, very little is known about the clinical profile and risk factors predicting mortality. The objective of our study was to determine the epidemiology and predictors of in-hospital DOI:10.2459/JCM.0000000000000222
Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
CE: Tripti; JCM-D-14-00249; Total nos of Pages: 6;
JCM-D-14-00249
2 Journal of Cardiovascular Medicine 2014, Vol 00 No 00
mortality in patients with PPCM. We also sought to analyze the outcome of PPCM stratified by the time of diagnosis – antepartum, peripartum and postpartum period.
Methods We analyzed the Nationwide Inpatient Sample (NIS) database for the period 2009–2010 from the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality (Rockville, Maryland, USA). It is the largest all-payer hospitalization database representing up to 8 million hospital stays from over 1000 hospitals in the United States. The data represent 20% of all inpatient admissions to nonfederal hospitals in the United States. All patients with listed diagnoses of PPCM in the NIS database using the Ninth Revision of International Classification of Diseases (ICD-9) 674.51–674.54 were included in the study. On the basis of the ICD-9 codes, we categorized PPCM into three groups that reflect the time of diagnosis – antepartum (674.53), peripartum (674.51, 674.52) and postpartum (674.54) groups. All hospitalizations of patients aged 15–60 years of age were included in the analysis. Patients were excluded if they had other possible causes for heart failure including takotsubo cardiomyopathy using corresponding ICD-9 codes. Age was represented as a continuous variable, whereas race was categorized as white, African-Americans, Asian, Hispanic, Native American or others. We used hospital and discharge weights to generate national estimates. We analyzed the prevalence of PPCM in each category of partum period and among different races. We looked for differences in demographic factors, in-hospital mortality, cardiovascular risk factors and other risk factors among different races and partum period. Primary outcome of
Statistical analysis
Categorical variables were represented as percentages [n (%)], whereas continuous variables were represented as mean SD if normally distributed, and median (interquartile range) if not normally distributed. Univariate regression analysis was done to determine predictors of mortality in PPCM. Stepwise multimodel logistic regression was done adjusting for demographic, cardiovascular and other risk factors. P value less than 0.05 was considered statistically significant. All statistical analyses were performed using STATA 10.0 (Statacorp, College Station, Texas, USA).
Results Demographic and risk factors in different partum periods
The prevalence of PPCM among women hospitalized between the age group 15–60 was 1 in 2367 (0.04%). The diagnosis was made in the postpartum period in 3741 patients (78%), in the peripartum period in 887 patients (18%) and in the antepartum period in 189 patients (4%) (Table 1). The mean age was 30.3 0.2
Demographic characteristics and risk factors in patients with peripartum cardiomyopathy stratified by partum period
Table 1 Variables
the study was to determine the in-hospital mortality rate. Demographic factors included were age and length of stay in the hospital. Hypertensive disorders were classified as pre-existing hypertension, gestational hypertension, preeclampsia, eclampsia and preeclampsia/ eclampsia superimposed on existing hypertension. Other cardiovascular risk factors included were diabetes mellitus, obesity and smoking. We analyzed commonly associated noncardiovascular conditions with PPCM, including twin gestations, premature labor and other associated conditions prevalent in our population (refer to supplement for ICD-9 codes used to identify these conditions).
a
N (%) Age Length of stay Hypertension class I Hypertension class II Hypertension class III Hypertension class IV Hypertension class V Diabetes Gestational diabetes Premature labor Tobacco use Obesity Twin gestation Drug abuse Thyroid dysfunction Thyroid dysfunction complicating pregnancy Mental disorders Mortality
Total
Antepartum
Peripartum
Postpartum
Pb
4859 30.3 0.2 5.6 (5.1–6.03) 1537 (32) 179 (3.6) 481 (9.8) 120 (2.5) 154 (3.2) 347 (7.1) 53 (1.1) 300 (6.2) 663 (14) 534 (11) 86 (9.7) 15 (0.3) 204 (4.2) 21 (0.4)
189 (4) 29.7 1 3.2 (2.2–4.2) 93 (49) 4 (2.1) 10 (5.3) 0 5 (2.6) 29 (15) 10 (5.3) 20 (11) 34 (18) 19 (10) 0 0 0 0
887 (18) 28.5 0.4 7.6 (6.4–8.8) 170 (19) 90 (10) 246 (28) 43 (4.8) 86 (9.6) 29 (3.3) 28 (3.2) 279 (31) 100 (11) 108 (12) 86 (9.7) 5 (0.5) 43 (4.8) 11 (1.2)
3741 (78) 30.7 0.2 5.2 (4.7–5.7) 1260 (34) 85 (2.3) 224 (5.9) 77 (2.1) 63 (1.7) 289 (7.7) 15 (0.4) 0 520 (14) 290 (7.7) 0 10 (0.3) 157 (4.2) 10 (0.3)
JCM-D-14-00249
Original article
Epidemiology and outcomes of peripartum cardiomyopathy in the United States: findings from the Nationwide Inpatient Sample Parasuram Krishnamoorthya, Jalaj Gargb, Chandrasekar Palaniswamyb, Ambarish Pandeyc, Hasan Ahmadb, William H. Frishmanb and Gregg Lanierb Aims Peripartum cardiomyopathy (PPCM) is defined as systolic heart failure within the last month of pregnancy or 5 months after delivery in the absence of any identifiable cause of heart failure. We aimed to investigate the prevalence of PPCM and predictors of in-hospital mortality in patients with PPCM. Methods We analyzed patients with diagnosis of PPCM from the Nationwide Inpatient Sample database using the Ninth Revision of International Classification of Diseases (ICD-9) from 2009 to 2010. We categorized PPCM (n U 4871) into three groups of presentation based on their ICD-9 codes: antepartum (674.53; n U 189), peripartum (674.51, 674.52; n U 887) and postpartum (674.54; n U 3741).
peripartum group. Asians had the highest mortality (8.3%). In multimodel regression analysis, Asians [odds ratio (OR) 9.68, 95% confidence interval (CI) 1.11–83.9, P U 0.03] and length of stay (OR 1.06, 95% CI 1.03–1.10, P < 0.01) were associated with increased mortality, whereas white women were associated with reduced mortality (OR 0.10, 95% CI 0.02–0.59, P U 0.01). Conclusion Although PPCM was prevalent in AfricanAmericans, Asians had higher in-hospital mortality, increased prevalence of preeclampsia and premature labor. Also, mortality rate was significantly higher in the postpartum group. J Cardiovasc Med 2014, 16:000–000
Results PPCM was more common in African-Americans (43.9%) as compared with white (40.8%), Hispanic (8.7%) and Asian (2.7%) women. Hypertensive disorders were classified as pre-existing hypertension (31.6%), gestational hypertension (3.7%), preeclampsia (9.9%), eclampsia (2.4%) and preeclampsia/eclampsia superimposed on hypertension (3.1%). Among different ethnicities, preexisting hypertension (1 : 2.3) and diabetes (1 : 10.4) were more prevalent in African-Americans, whereas preeclampsia (1 : 4.3) and premature labor (1 : 5.4) were more common in Asians. In-hospital mortality rate was 1.8%, with 2.1% in the postpartum and 0.5% in the
Introduction Peripartum cardiomyopathy (PPCM), defined as idiopathic dilated cardiomyopathy associated with pregnancy, is a rare and potentially fatal disease.1,2 The first case was described in the 1930s when it was recognized as a distinct clinical entity.3,4 The reported incidence in the United States varies from 1 : 2289 to 1 : 4000 live births.5 It has a highly unpredictable clinical course, varying from complete recovery6–8 to rapid progression and end-stage heart failure in a few days to weeks.5 The diagnostic criteria are as follows: development of cardiac failure in the last month of pregnancy or within 5 months of delivery; absence of an identifiable cause for the cardiac failure other than pregnancy; absence of recognizable heart disease before the last month of pregnancy and left ventricular systolic dysfunction (LVSD) with left ventricular ejection fraction (LVEF) less than 45% by echocardiography, fractional shortening below 30% or 1558-2027 ß 2014 Italian Federation of Cardiology
Keywords: epidemiology, mortality, outcomes, peripartum cardiomyopathy, preeclampsia, risk factors a
Department of Medicine, Englewood Hospital and Medical Center, New Jersey, Department of Internal Medicine, Division of Cardiology, Westchester Medical Center, New York Medical College, New York and cDepartment of Medicine, Division of Cardiology, University of Texas, Texas, USA
b
Correspondence to Parasuram Krishnamoorthy, MD, Department of Internal Medicine, Englewood Hospital and Medical Center, Englewood, NJ 07631, USA Tel: +1 732 501 5100; fax: +1 201 894 0839; e-mail: [email protected] Received 19 April 2014 Revised 26 June 2014 Accepted 3 September 2014
both.1,5,9 However, Elkayam et al.10 and Sliwa et al.11 demonstrated that patients could present with similar symptoms even before the last gestational month, with no significant difference in maternal outcome, and hence could represent a continuum in the spectrum of the same disease. The cause remains unclear and appears to be multifactorial with the Afro-American race being the strongest risk factor.8 Other risk factors identified are twin gestation, multiparity,12 advanced maternal age13 and preeclampsia.14 Other pathological processes including myocarditis, autoimmunity15,16 and oxidative stress17 have also been linked to PPCM. Blauwet et al.18 and Goland et al.19 reported predictors of clinical outcomes in small cohorts of patients with PPCM. However, very little is known about the clinical profile and risk factors predicting mortality. The objective of our study was to determine the epidemiology and predictors of in-hospital DOI:10.2459/JCM.0000000000000222
Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
CE: Tripti; JCM-D-14-00249; Total nos of Pages: 6;
JCM-D-14-00249
2 Journal of Cardiovascular Medicine 2014, Vol 00 No 00
mortality in patients with PPCM. We also sought to analyze the outcome of PPCM stratified by the time of diagnosis – antepartum, peripartum and postpartum period.
Methods We analyzed the Nationwide Inpatient Sample (NIS) database for the period 2009–2010 from the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality (Rockville, Maryland, USA). It is the largest all-payer hospitalization database representing up to 8 million hospital stays from over 1000 hospitals in the United States. The data represent 20% of all inpatient admissions to nonfederal hospitals in the United States. All patients with listed diagnoses of PPCM in the NIS database using the Ninth Revision of International Classification of Diseases (ICD-9) 674.51–674.54 were included in the study. On the basis of the ICD-9 codes, we categorized PPCM into three groups that reflect the time of diagnosis – antepartum (674.53), peripartum (674.51, 674.52) and postpartum (674.54) groups. All hospitalizations of patients aged 15–60 years of age were included in the analysis. Patients were excluded if they had other possible causes for heart failure including takotsubo cardiomyopathy using corresponding ICD-9 codes. Age was represented as a continuous variable, whereas race was categorized as white, African-Americans, Asian, Hispanic, Native American or others. We used hospital and discharge weights to generate national estimates. We analyzed the prevalence of PPCM in each category of partum period and among different races. We looked for differences in demographic factors, in-hospital mortality, cardiovascular risk factors and other risk factors among different races and partum period. Primary outcome of
Statistical analysis
Categorical variables were represented as percentages [n (%)], whereas continuous variables were represented as mean SD if normally distributed, and median (interquartile range) if not normally distributed. Univariate regression analysis was done to determine predictors of mortality in PPCM. Stepwise multimodel logistic regression was done adjusting for demographic, cardiovascular and other risk factors. P value less than 0.05 was considered statistically significant. All statistical analyses were performed using STATA 10.0 (Statacorp, College Station, Texas, USA).
Results Demographic and risk factors in different partum periods
The prevalence of PPCM among women hospitalized between the age group 15–60 was 1 in 2367 (0.04%). The diagnosis was made in the postpartum period in 3741 patients (78%), in the peripartum period in 887 patients (18%) and in the antepartum period in 189 patients (4%) (Table 1). The mean age was 30.3 0.2
Demographic characteristics and risk factors in patients with peripartum cardiomyopathy stratified by partum period
Table 1 Variables
the study was to determine the in-hospital mortality rate. Demographic factors included were age and length of stay in the hospital. Hypertensive disorders were classified as pre-existing hypertension, gestational hypertension, preeclampsia, eclampsia and preeclampsia/ eclampsia superimposed on existing hypertension. Other cardiovascular risk factors included were diabetes mellitus, obesity and smoking. We analyzed commonly associated noncardiovascular conditions with PPCM, including twin gestations, premature labor and other associated conditions prevalent in our population (refer to supplement for ICD-9 codes used to identify these conditions).
a
N (%) Age Length of stay Hypertension class I Hypertension class II Hypertension class III Hypertension class IV Hypertension class V Diabetes Gestational diabetes Premature labor Tobacco use Obesity Twin gestation Drug abuse Thyroid dysfunction Thyroid dysfunction complicating pregnancy Mental disorders Mortality
Total
Antepartum
Peripartum
Postpartum
Pb
4859 30.3 0.2 5.6 (5.1–6.03) 1537 (32) 179 (3.6) 481 (9.8) 120 (2.5) 154 (3.2) 347 (7.1) 53 (1.1) 300 (6.2) 663 (14) 534 (11) 86 (9.7) 15 (0.3) 204 (4.2) 21 (0.4)
189 (4) 29.7 1 3.2 (2.2–4.2) 93 (49) 4 (2.1) 10 (5.3) 0 5 (2.6) 29 (15) 10 (5.3) 20 (11) 34 (18) 19 (10) 0 0 0 0
887 (18) 28.5 0.4 7.6 (6.4–8.8) 170 (19) 90 (10) 246 (28) 43 (4.8) 86 (9.6) 29 (3.3) 28 (3.2) 279 (31) 100 (11) 108 (12) 86 (9.7) 5 (0.5) 43 (4.8) 11 (1.2)
3741 (78) 30.7 0.2 5.2 (4.7–5.7) 1260 (34) 85 (2.3) 224 (5.9) 77 (2.1) 63 (1.7) 289 (7.7) 15 (0.4) 0 520 (14) 290 (7.7) 0 10 (0.3) 157 (4.2) 10 (0.3)
