Harms Were Rarely Specified or Reported in Public Health Randomized Trials: A Meta-Epidemiological Study

To characterize harms specification, harms reporting, concordance between specified and reported harms, transparency about harms reporting criteria, and equity-related harms considerations in randomized controlled trials (RCTs) of public health interventions.

We conducted a meta-epidemiological study of 100 RCTs of public health interventions whose primary full-text report was indexed in PubMed in 2023. Using the publication and publicly-linked documents (registrations, protocols, supplements), we assessed harms specification, harms reporting, concordance, transparency of reporting criteria, and whether reported harms were grouped by PROGRESS-Plus equity-related factors.

Only 25% (25/100) specified at least one harm, and 23% (23/100) reported any harms, while 72% (72/100) neither specified nor reported harms. Among 28 trials that either specified or reported harms, 12 (43%) reported all specified harms, 8 (29%) reported only a subset, and 8 (29%) showed other discordance. No trial specified harms reporting criteria, and none reported harms using identifiable criteria. Trials with a registry listing and those with an identified protocol had higher odds of harms specification compared with trials without a registry or protocol (OR = 4.7 [1.5, 14.3] and OR = 3.9 [1.5, 10.1], respectively); trials tested pharmacological interventions also showed higher odds of specification compared with other intervention types (OR = 9.8 [1.9, 49.9]). Similarly, harms reporting was higher in trials with a registry or protocol (OR = 4.0 [1.3, 12.4] and OR = 3.8 [1.4, 10.0], respectively). Although 89% of trial reports considered at least one equity-related factor among participant characteristics, none reported harms stratified by these factors. Compared with a parallel biomedical sample, public health RCTs specified and reported harms far less often.

Most public health RCTs in this sample did not publicly specify or report harms. Prespecifying how harms will be assessed and fully reporting the findings would better support decisions about adopting, modifying, or expanding public health programs. Because the sample included 100 public health RCTs and harms-related outcomes were sparse, subgroup findings should be interpreted as exploratory.