Effect Sizes and Primary Outcomes in Large-Budget, Cardiovascular-Related Behavioral Randomized Controlled Trials Funded by NIH Since 1980.

PURPOSE

We reviewed large-budget, National Institutes of Health (NIH)-supported randomized controlled trials (RCTs) with behavioral interventions to assess (1) publication rates, (2) trial registration, (3) use of objective measures, (4) significant behavior and physiological change, and (5) effect sizes.

METHODS

We identified large-budget grants (>$500,000/year) funded by NIH (National Heart Lung and Blood Institute (NHLBI) or National Institute of Diabetes & Digestive and Kidney Diseases (NIDDK)) for cardiovascular disease (dates January 1, 1980 to December 31, 2012). Among 106 grants that potentially met inclusion criteria, 20 studies were not published and 48 publications were excluded, leaving 38 publications for analysis. ClinicalTrials.gov abstracts were used to determine whether outcome measures had been pre-specified.

RESULTS

Three fourths of trials were registered in ClinicalTrials.gov and all published pre-specified outcomes. Twenty-six trials reported a behavioral outcome with 81 % reporting significant improvements for the target behavior. Thirty-two trials reported a physiological outcome. All were objectively measured, and 81 % reported significant benefit. Seventeen trials reported morbidity outcomes, and seven reported a significant benefit. Nine trials assessed mortality, and all were null for this outcome.

CONCLUSIONS

Behavioral trials complied with trial registration standards. Most reported a physiological benefit, but few documented morbidity or mortality benefits.