As the population with multiple chronic conditions (MCC) increases, it is essential that randomized controlled trials (RCTs) include MCC to ensure the appropriateness of applying trial results to the broader population. However, previous reviews of RCTs not limited by intervention type have found that individuals with MCC are often excluded, and when MCC are reported in patient characteristics, details are sparse. A thorough systematic review of the inclusion of MCC in RCTs of behavioral and/or psychosocial interventions is needed to provide important insight into the applicability of results and to identify gaps in the design and implementation of behavioral and/or psychosocial interventions in prevention and control of chronic conditions.
With this review we seek to test the hypothesis that individuals with multiple chronic conditions are underrepresented in RCTs of behavioral and psychosocial interventions published in general medical, behavioral medicine, behavioral science, health psychology, social science, and public health journals.
The goals of the review are to: (1) conduct a systematic review to assess the frequency with which research participants with MCC are represented in all or a representative subset of RCTs of behavioral and psychosocial interventions published in general medical and specialized journals, published within the last decade or decade and a half, that focus on behavioral medicine and behavioral science, health psychology, social science, and public health; (2) determine whether there are significant differences by type of journal or over time in the frequency with which research participants with MCC are represented in RCTs of behavioral and psychosocial interventions.
This review considered 20 chronic conditions. The selected conditions were taken from a list compiled by an MCC working group at the Office of the Assistant Secretary of Health (OASH) within the US Department of Health and Human Services (HHS). These chronic conditions meet the definition for chronicity, are prevalent and have potential to be modifiable by public health and/or clinical interventions.
A certified MLS librarian with expertise in searching for systematic reviews designed to retrieve all reported RCTs in adults regarding chronic illness in PubMed MEDLINE and EMBASE. Database supplied limits were used to limit by three year clusters, 2000-2004, 2005-2009, and 2010-2014. Searches were completed in February 2015.
Within each 5-year time period, search results were randomly ordered and selection criteria was applied by two independent reviewers until 200 articles meeting inclusion criteria were selected per time period. Selection criteria were primary reports of RCTs of behavioral and/or psychosocial interventions targeting adults with specified chronic conditions of interest.
Data collection and analysis:
Data were extracted independently by two trained readers using a standardized form. Risk of bias was assessed using a modified version of the Cochrane Collaboration tool for assessing risk of bias. After extraction by each reader, records were compared and differences were adjudicated by a third party. Data was managed in REDCap.
600 RCTs testing behavioral and/or psychosocial interventions were included. Studies were mostly from specialty journals (83.8%). and about half were from North America (51.5%). The most common intervention focuses were psychological well-being (35.5%) and weight management/diet/physical activity (27.5%). Mean risk of bias score improved over time (p<0.001).
Targeting MCC directly was rare (4.3%). The most commonly targeted individual conditions were cancer (17.0%) and diabetes (13.0%). Exclusion criteria for MCC were categorized as specific (naming specific conditions), general (using general terms for chronic conditions), or vague (criteria without clear definition that is likely to result in exclusion of MCC). Overall, 68.3% of trials included general, specific, or vague exclusion criteria for MCC. This did not change over time (p=0.87). The most common specific conditions excluded were substance abuse disorders (19.0%), dementia (16.9%), and schizophrenia (14.1%). Using a maximum age as exclusion criteria was common (27.8%), and in these trials the median maximum age was 65.0. When exclusions for MCC were reported, only 15.9% of trials identified the number of individuals excluded for these reasons during screening.
The inclusion of MCC could be identified in 35.8% of trials. Condition specific descriptions were more common than general descriptions (28.7% vs 11.3%). Of those trials that reported including MCC, the prevalence of MCC was reported in 59.5% of trials. Of trials reporting specific comorbidities of the index conditions, the mean number of additional conditions reported was 2.1. Comorbidities were considered in analysis in 5.2% of all trials, and 12.1% of trials reporting inclusion of MCC.
In a representative sample of RCTs testing behavioral and/or psychosocial interventions published over the last 15 years (2000-2014), trials rarely target individuals with MCC. Additionally, they frequently exclude individuals with MCC due to specific, general, or vague exclusion criteria, and exclusion criteria based on factors correlated with MCC, such as age. When MCC are used as exclusion criteria, information regarding to what extent potential participants were excluded for having MCC is usually not provided. When trials indicated that some participants did have MCC, the prevalence of MCC either by general measure or by individual conditions is often not specified. Although our results suggest that individuals with MCC are not appropriately represented in RCTs of behavioral and/or psychosocial interventions, perhaps of bigger concern is that it is often difficult to determine if and to what extent MCC are included due to the poor reporting quality of relevant information in trials. Collectively these factors limit the ability to judge the appropriateness of applying trial results to the broader population. Additionally this review identifies possible areas for further study to address the shortcomings of existing evidence of the representation of individuals with MCC in RCTs.