Weight change among patients engaged in medication treatment for opioid use disorder: a scoping review.

Background: Medication treatment for opioid use disorder (MOUD) is an instrumental tool in combatting opioid use and overdose. Excess weight gain associated with MOUD initiation is a potential barrier that is not well understood.Objectives: Conduct a scoping review of available studies investigating the effect of MOUD on weight.Methods: Included studies consisted of adults taking any type of MOUD (e.g. methadone, buprenorphine/naloxone, naltrexone) with data on weight or body mass index for at least two time points. Evidence was synthesized using qualitative and descriptive approaches, and predictors of weight gain including demographics, comorbid substance use, and medication dose were examined.Results: Twenty-one unique studies were identified. Most studies were uncontrolled cohort studies or retrospective chart reviews testing the association between methadone and weight gain (n = 16). Studies examining 6 months of methadone treatment reported weight gain ranging from 4.2 to 23.4 pounds. Women appear to gain more weight from methadone than men, while patients using cocaine may gain less. Racial and ethnic disparities were largely unexamined. Only three case reports and two nonrandomized studies examined the effects of either buprenorphine/naloxone or naltrexone, and potential associations with weight gain were not clear.Conclusion: The use of methadone as an MOUD appears to be associated with mild to moderate weight gain. In contrast, there is little data supporting or refuting weight gain with buprenorphine/naloxone or naltrexone. Providers should discuss the potential risk for weight gain with patients as well as prevention and intervention methods for excess weight gain.

Expectations for Improvement: A Neglected but Potentially Important Covariate or Moderator for Chronic Pain Clinical Trials.

Variability in pain-related outcomes can hamper assay sensitivity of chronic pain clinical trials. Expectations of outcome in such trials may account for some of this variability, and thereby impede development of novel pain treatments. Measurement of participants' expectations prior to initiating study treatment (active or placebo) is infrequent, variable, and often unvalidated. Efforts to optimize and standardize measurement, analysis, and management of expectations are needed. In this Focus Article, we provide an overview of research findings on the relationship between baseline expectations and pain-related outcomes in clinical trials of pharmacological and nonpharmacological pain treatments. We highlight the potential benefit of adjusting for participants' expectations in clinical trial analyses and draw on findings from patient interviews to discuss critical issues related to measurement of expectations. We conclude with suggestions regarding future studies focused on better understanding the utility of incorporating these measures into clinical trial analyses. PERSPECTIVE: This focus article provides an overview of the relationship between participants' baseline expectations and pain-related outcomes in the setting of clinical trials of chronic pain treatments. Systematic research focused on the measurement of expectations and the impact of adjusting for expectations in clinical trial analyses may improve assay sensitivity.