Increases in body mass index following initiation of methadone treatment

Despite the clear efficacy of methadone for opioid dependence, one less desirable phenomenon associated with methadone may be weight gain. We examined changes in body mass index (BMI) among patients entering methadone treatment. A retrospective chart review was conducted for 96 patients enrolled in an outpatient methadone clinic for ≥ 6 months. The primary outcome of BMI was assessed at intake and a subsequent physical examination approximately 1.8 ± 0.95 years later. Demographic, drug use and treatment characteristics were also examined. There was a significant increase in BMI following intake (p<0.001). Mean BMIs increased from 27.2 ± 6.8 to 30.1 ± 7.7 kg/m(2), translating to a 17.8-pound increase (10% increase in body weight) in the overall patient sample. Gender was the strongest predictor of BMI changes (p < 0.001), with significantly greater BMI increases in females than males (5.2 vs. 1.7 kg/m(2), respectively). This translates to a 28-pound (17.5%) increase in females vs. a 12-pound (6.4%) increase in males. In summary, methadone treatment enrollment was associated with clinically significant weight gain, particularly among female patients. This study highlights the importance of efforts to help patients mitigate weight gain during treatment, particularly considering the significant health and economic consequences of obesity for individuals and society more generally.