Background: Selective reporting of outcomes impairs awareness of health technology effects. Objective: To assess selective reporting of renal adverse reactions in clinical trials on selective cyclooxygenase-2 inhibitor anti-inflammatory drugs (coxibs). Methods: A cross-sectional analysis based on a systematic review on the renal adverse effects of coxibs (registered in PROSPERO: CRD42022380227). Studies were assessed for selective reporting of outcomes the Cochrane Risk of Bias tool’s item 6. Randomized controlled trials (RCTs) that reported only predefined adverse events or if they reached an incidence threshold were categorized as at high risk. We collected the 2022 Journal Impact Factor (JIF) and percentage of gold open access from Journal Citation Reports website. Dates of submission and approval were extracted to calculate the length of peer review, in days. We investigated factors associated to the selective reporting using qui-squared test or t-test (p<0.05). All analyses were performed in Stata v.14.2. Results: Selective reporting was observed in 30/49 included studies; 47 had JIF and 31 were published from 1999-2006. Over half of the studies were conducted in North America (n=35) and Europe (n=14) and length of peer review was 170.12±120.97 (n=26). RCTs with selective reporting established thresholds to report reactions: 1-2% (n=4), 3% (n=8) and 4-5% (n=7) or reported only pre-specified adverse events (n=11). Selective reporting was significantly higher in journals of lower JIF (n=29; 6.08±6.47 vs. n=18; 28.97±54.52; p=0.029). Osteoarthritis RCTs had more selective reporting (20/26 vs. 10/23; p=0.016). Similarly, of the 22 studies lasting up to 6 weeks, 17 had selective reporting, which was significantly higher than RCTs of longer duration (13/27; p=0.037). Most studies (41/49) were funded by pharmaceutical industry. No significant differences were observed in length of peer review, open access, publication date, and number of participants (p>0.05). Conclusion: Selective reporting a common concern in coxibs’ RCTs, more frequent in less influential journals, RCTs on osteoarthritis, and shorter duration studies, potentially underestimates the renal risks of coxibs.
Relevance and importance to patients: Renal effects, including edema and hypertension, were frequently unreported in RCTs assessing anti-inflammatory drugs' cardiovascular and gastrointestinal impacts, posing significant risks to patients by neglecting critical adverse effects.