OBES SURG DOI 10.1007/s11695-015-1634-6

ORIGINAL CONTRIBUTIONS

Bariatric Surgery Patients’ Response to a Chronic Pain Rehabilitation Program Anilga Tabibian & Karen B. Grothe & Manpreet S. Mundi & Todd A. Kellogg & Matthew M. Clark & Cynthia O. Townsend

# Springer Science+Business Media New York 2015

Abstract Background Chronic pain (CP) is a prevalent and disabling diagnosis in obese individuals, but how bariatric surgery patients respond to chronic pain rehabilitation treatment programs has not previously been described. Objectives The aim of this study was to compare treatment outcomes of a chronic pain rehabilitation program (psychological and pain variables, medication use, treatment completion rates) for post-bariatric surgery patients to those of a nonbariatric surgery control group. Setting Three week outpatient multidisciplinary chronic pain program in an academic medical center. Methods This was a retrospective case-control study. Medical records of patients admitted to the Pain Rehabilitation Center at Mayo Clinic from 2008 to 2012 were reviewed. One hundred six patients with a history of bariatric surgery (cases) were identified and matched to 106 patients without a history of bariatric surgery (controls) on age, gender, and smoking status (n=202). Matched t tests and McNemar’s tests were used for analyses. Results Mean age was 46 years; 91 % were female and 58 % were non-smokers. The majority of cases (71 %) had undergone Roux-en-Y gastric bypass. Bariatric patients had higher A. Tabibian (*) : K. B. Grothe : M. M. Clark Department of Psychiatry and Psychology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA e-mail: [email protected] M. S. Mundi Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN, USA T. A. Kellogg Department of General Surgery, Mayo Clinic, Rochester, MN, USA C. O. Townsend VA Health Care System, Minneapolis, MN, USA

rates of benzodiazepine use at discharge (33 vs. 19 %, p = 0.0433) and were less likely to complete treatment (87 vs. 97 %, p=0.007) compared to controls. Morphine equivalent use for cases was 127.3 mg ± 135.4 (n = 62) compared to 88.3 mg±95.3 (n=62), p=0.12, for controls at admission. Conclusions These results suggest that bariatric patients may be at risk for treatment non-adherence and have difficulty reducing medication use in the treatment of chronic pain. Keywords Bariatric surgery . Chronic pain . Opioid use . Morphine equivalents

Introduction In the USA, it is estimated that more than one in three adults is obese [1] and obesity is associated with medical comorbidities and poor quality of life [1]. Pain is also prevalent in our society as one in five adults has chronic non-malignant pain (CP) [2, 3]. Obesity and CP are directly associated as a result of multiple factors, including increased load on weight-bearing joints and inflammation [4–7]. Currently, the most effective treatment for morbid obesity is bariatric surgery [8, 9]. Among appropriate candidates, bariatric surgery can significantly improve obesity-related comorbidities and health-related quality of life (HRQOL) [6, 8, 10]. CP is also challenging to effectively manage and is often treated with opioid medications despite lack of long-term evidence for efficacy [1, 11–13]. There is a growing body of evidence supporting the efficacy of multidisciplinary pain rehabilitation programs in managing CP [2]. While the association between obesity and CP has been well documented, relatively little published data exist regarding treatment of CP in patients who have undergone bariatric

OBES SURG

Materials and Methods

established goal of the program [2, 17–19]. Thus, information on opioid use (yes/no) and morphine equivalent dose was collected for all patients at admission and discharge and determined by a combination of patient self-report and review of pharmacy records [18]. For patients with daily opioid use, the opioid dose was converted to daily morphine equivalents using an equianalgesic conversion software program [18, 19]. Patients for whom morphine equivalents could not be determined (e.g., on PRN opioids) were censored from analyses of this variable.

Study Design and Participants

Medication Use, Alcohol Use, and Treatment Outcomes

A retrospective case-control study of adult patients admitted to the Pain Rehabilitation Center (PRC) from March 2008 through December 2012 was conducted. For this type of study, formal consent is not required. One hundred six consecutive patients with a history of bariatric surgery (cases) were identified. For these 106 cases, 106 controls were selected (i.e., PRC patients with no history of bariatric surgery) matched on age, gender, and smoking status. We matched on smoking status because smoking is associated with greater levels of pain, depression and anxiety, higher doses of prescription opioids, and worse physical functioning [15]. This study was approved by the Institutional Review Board at Mayo Clinic, Rochester.

Benzodiazepine use (yes/no), non-steroidal anti-inflammatory drug (NSAID) use (yes/no), alcohol use (yes/no), and frequency were collected at admission and discharge. Program completion status was collected for all patients.

surgery. A subgroup of patients continues to struggle with management of chronic pain even after achieving significant weight loss [14]. Therefore, the aim of this study was to compare treatment outcomes from a chronic pain rehabilitation program (psychological and pain variables, medication use, treatment completion rates) for post-bariatric surgery patients to a non-bariatric surgery control group.

Treatment Setting The PRC program at Mayo Clinic is an interdisciplinary, intensive, outpatient 3-week program. Patients with persistent CP who have experienced a significant deterioration in emotional and physical functioning are program eligible [13, 16]. The program employs a group-based cognitive-behavioral intervention, and patients meet 8 h a day for 15 consecutive weekdays. The primary goal of treatment is functional restoration, including reduction in medication use (e.g., opioids and benzodiazepines). Demographic and Clinical Variables Demographic and clinical variables were collected at admission and included age, sex, ethnicity, marital status, years of education, smoking status, and body mass index (BMI). For bariatric patients, type and date of bariatric surgery and pain onset (i.e., before or after bariatric surgery) were obtained via medical record review. Pain variables collected for all patients included pain site, pain duration, and opioid use. Opioid Use and Morphine Equivalents Patients entering the PRC program were on daily, pro re nata (PRN), or no opioid medications. Tapering off of opioids is an

Measures of Physical and Emotional Functioning Psychosocial impact of chronic pain was assessed with the Multidimensional Pain Inventory (MPI), a 52-item self-report questionnaire with good psychometric properties [13, 20]. Four of 12 subscales were used: pain severity, life interference due to pain, perceived life control, and affective distress [2, 16, 17]. Lower scores on the pain severity, life interference due to pain, and affective distress subscales signify less impairment, whereas the opposite is true for the perceived life control subscale. Health status was assessed using the Short Form-36 Health Status Questionnaire (SF-36), a 36-item reliable and valid self-report questionnaire [21, 22]. Five of eight subscales were used: general health, physical functioning, role physical, role emotional, and social functioning [2, 16, 17]. For all subscales, higher scores indicate better health status. Depressive symptoms were assessed using the Center for Epidemiologic Studies-Depression (CES-D) scale, a 20-item reliable and valid self-report questionnaire [23]. Scores range from 0 to 60, and higher scores indicate greater depression. The Pain Catastrophizing Scale (PCS), a 13-item reliable and valid self-report questionnaire, examines negative emotions associated with pain experiences [24]. Scores range from 0 to 52, and higher scores indicate greater pain catastrophizing [2, 13, 16, 18]. Data Analysis Data were summarized as mean (±standard deviation) or proportions. Paired t test and McNemar’s test were used to compare continuous and categorical variables, respectively, between bariatric surgery patients (cases) and non-bariatric chronic pain patients (controls). Missing data from one participant excluded the pair from the analyses. Tests of significance

OBES SURG

were two tailed, with an alpha level of 0.05. Statistical analyses were conducted using JMP statistical software version 9.0 (SAS, Cary, NC).

Results Demographic and Clinical Variables

Pain Onset Sixty-two percent of cases reported pain before bariatric surgery, 38 % reported pain after bariatric surgery, and 14 % did not specify pain onset. Twenty percent of cases reported CP resulted from bariatric surgery, with 72 % of these patients endorsing abdominal pain as the primary pain site (n=13). Pain Variables

The mean age was 46 years (±10.6, range 22–71 years); 91 % were female and 58 % were non-smokers. The only difference found between cases and controls was in BMI, which was higher for bariatric patients (33.2 vs. 29.9 kg/m2, range 14.3–93.2). These and other baseline demographic and clinical characteristics are summarized in Table 1. Bariatric Surgery-Specific Variables (Cases)

The three most common self-reported pain sites for cases were back pain (27 %), fibromyalgia pain (25 %), and headache pain (11 %). This differed slightly for controls, with fibromyalgia being the most common pain site (25 %), followed by generalized non-fibromyalgia pain (15 %) and back pain (17 %). Pain duration differed between groups, with cases averaging 12.8 years±11.1 and controls averaging 9.8 years±9.5 (p=0.02).

Bariatric Surgery Type and Date

Medication and Alcohol Use

Seventy-five cases (71 %) had undergone laparoscopic Rouxen-Y gastric bypass (LRYGB) surgery, while 6 (6 %) had open RYGB, 11 (10 %) had another type of bariatric procedure (e.g., duodenal switch, vertical banded gastroplasty, gastric stapling), and 14 (13 %) had revisions. Year of surgery ranged from 1975 to 2010, with the majority of patients (61 %) having undergone surgery in the year 2000 or later.

Opioid Use and Morphine Equivalents

Table 1

Demographic and clinical variables

Variables

Bariatric (n=106)

Non-bariatric (n=106)

p value

Age, mean (SD), years 46.1 (10.6) 46.1 (10.6) n (%), sex 96 (91 %), female 96 (91 %), female Smoking status, n (%) Never smoked 62 (58 %) 62 (58 %) Former smoker Current smoker Education, mean (SD), years Marital status, n (%) Single Married Separated/divorced Widowed Ethnicity/race, n (%) Caucasian African-American Other including Hispanic BMI, mean (SD)

There was no difference in opioid use duration (4.1±6.7 vs. 3.5±5.8 years, p=0.85, n=82), or the proportion of patients on opioid medications between cases and controls at admission (67 vs. 65 %, p=0.73, n=106) or discharge (10 vs. 9 %, p=0.29, n=106). The mean morphine equivalent use for cases on daily opioids was 127.3 mg±135.4 (n=62) compared to 88.3 mg±95.3 (n=62), p=0.12, for controls at admission. At discharge, mean morphine equivalent use was 95.1±137.0 (n=10) for cases compared to 58.8 mg±69.9 (n=7, p=0.47) for controls, including non-completers (see Table 2). Benzodiazepine Use At admission, there was no significant difference in the proportion of patients on benzodiazepines between cases and controls (63 vs. 61 %, p=0.13). At discharge, a higher proportion of cases were on benzodiazepines (33 vs. 19 %, p=0.04).

22 (21 %) 22 (21 %) 14.5 (2.1)

22 (21 %) 22 (21 %) 14.7 (2.8)

21 (20 %) 66 (62 %) 10 (10 %) 9 (8 %)

17 (16 %) 78 (73 %) 6 (6 %) 5 (5 %)

99 (93 %) 4 (4 %)

99 (93 %) 1 (1 %)

Alcohol Use and Frequency

3 (3 %)

6 (6 %)

33.2 (8.3)

29.9 (10.4)

Bariatric patients reported less alcohol use (BDo you drink alcohol?^ yes/no) vs. controls (29 vs. 41 %, p=0.05), with no difference between groups for alcohol frequency (p=0.94).

0.57 0.82

NSAID Use At admission, a higher proportion of controls were on NSAI Ds compared to cases (51 vs. 41 %, p

Bariatric Surgery Patients' Response to a Chronic Pain Rehabilitation Program.

Chronic pain (CP) is a prevalent and disabling diagnosis in obese individuals, but how bariatric surgery patients respond to chronic pain rehabilitati...
198KB Sizes 3 Downloads 7 Views