Multimorbidity in randomized controlled trials of behavioral interventions: A systematic review.

Objective: As the population with multiple chronic conditions (MCC) increases, it is essential that randomized controlled trials (RCTs) consider MCC. Behavioral interventions have the potential to positively impact MCC patient outcomes; however, a comprehensive review of consideration of MCC in these trials has not been conducted. The purpose of this systematic review is to determine the frequency with which participants with MCC are represented in behavioral intervention RCTs targeting chronic illness published 2000-2014.

Method: MEDLINE and EMBASE were searched from 2000 to 2014 to identify RCTs testing behavioral interventions among adults with chronic illness. A random sampling selection process was performed to identify 600 eligible studies representative of the literature. Two reviewers independently extracted information on consideration of MCC in eligibility criteria and evaluated the reporting and consideration of MCC in trial analyses. Risk of bias was assessed using the Cochrane Collaboration Risk of Bias Tool.

Results: In 600 behavioral intervention RCTs, targeting MCC was rare (4.3%). Exclusion of MCC was common (68.3%) and was done through general, specific, or vague exclusion criteria. 218 (36.3%) trials reported presence of MCCs through general or condition-specific measures. Comorbidities were only considered in 4.8% of all trial analyses.

Conclusions: In this comprehensive systematic review of 600 studies published from 2000-2014, RCTs testing behavioral interventions rarely consider individuals with MCC, limiting generalizability. Given the public health relevance and limited evidence base, this work highlights the urgent need to improve the consideration of MCC in clinical trial research. (PsycINFO Database Record (c) 2019 APA, all rights reserved).