Gender disparities in access and retention in outpatient methadone treatment for opioid use disorder in low-income urban communities

The Lancet, 389(10077), 1453-1463

This paper reviews the literature examining characteristics associated with treatment outcome in women with substance use disorders. A search of the English language literature from 1975 to 2005 using Medline and PsycInfo databases found 280 relevant articles. Ninety percent of the studies investigating gender differences in substance abuse treatment outcomes were published since 1990, and of those, over 40% were published since the year 2000. Only 11.8% of these studies were randomized clinical trials. A convergence of evidence suggests that women with substance use disorders are less likely, over the lifetime, to enter treatment compared to their male counterparts. Once in treatment, however, gender is not a significant predictor of treatment retention, completion, or outcome. Gender-specific predictors of outcome do exist, however, and individual characteristics and treatment approaches can differentially affect outcomes by gender. While women-only treatment is not necessarily more effective than mixed-gender treatment, some greater effectiveness has been demonstrated by treatments that address problems more common to substance-abusing women or that are designed for specific subgroups of this population. There is a need to develop and test effective treatments for specific subgroups such as older women with substance use disorders, as well as those with co-occurring substance use and psychiatric disorders such as eating disorders. Future research on effectiveness and cost-effectiveness of gender-specific versus standard treatments, as well as identification of the characteristics of women and men who can benefit from mixed-gender versus single-gender treatments, would advance the field.

To examine patient and medication characteristics associated with retention and continued illicit opioid use in methadone (MET) versus buprenorphine/naloxone (BUP) treatment for opioid dependence. This secondary analysis included 1267 opioid-dependent individuals participating in nine opioid treatment programs between 2006 and 2009 and randomized to receive open-label BUP or MET for 24 weeks. The analyses included measures of patient characteristics at baseline (demographics; use of alcohol, cigarettes and illicit drugs; self-rated mental and physical health), medication dose and urine drug screens during treatment, and treatment completion and days in treatment during the 24-week trial. The treatment completion rate was 74% for MET versus 46% for BUP (P < 0.01); the rate among MET participants increased to 80% when the maximum MET dose reached or exceeded 60 mg/day. With BUP, the completion rate increased linearly with higher doses, reaching 60% with doses of 30-32 mg/day. Of those remaining in treatment, positive opioid urine results were significantly lower [odds ratio (OR) = 0.63, 95% confidence interval (CI) = 0.52-0.76, P < 0.01] among BUP relative to MET participants during the first 9 weeks of treatment. Higher medication dose was related to lower opiate use, more so among BUP patients. A Cox proportional hazards model revealed factors associated with dropout: (i) BUP [versus MET, hazard ratio (HR) = 1.61, CI = 1.20-2.15], (ii) lower medication dose (<16 mg for BUP, <60 mg for MET; HR = 3.09, CI = 2.19-4.37), (iii) the interaction of dose and treatment condition (those with higher BUP dose were 1.04 times more likely to drop out than those with lower MET dose, and (iv) being younger, Hispanic and using heroin or other substances during treatment. Provision of methadone appears to be associated with better retention in treatment for opioid dependence than buprenorphine, as does use of provision of higher doses of both medications. Provision of buprenorphine is associated with lower continued use of illicit opioids. © 2013 Society for the Study of Addiction.