Breaking the silence of sharing data in medical research.

Data sharing is highly advocated in the scientific community, with numerous organizations, funding agencies, and journals promoting transparency and collaboration. However, limited research exists on actual data sharing practices. We conducted a comprehensive analysis of the intent to share individual participant data (IPD) in a total of 313,990 studies encompassing clinical trials and observational studies obtained from ClinicalTrials.gov, spanning the period from 2000 to 2023. Our study found that only 10.3% of principal investigators (PIs) expressed intent to share IPD. Clinical trials were more likely to share data than observational studies (odds ratio, OR = 1.98, 95% CI: 1.92-2.04). Large sample size studies were 1.69 times more likely to share data than small ones (95% CI: 1.65-1.73). Studies registered after 2018 were 1.6 times more likely to share data (95% CI: 1.57-1.64) than before 2019. NIH and other US Federal agency-funded studies had 1.49 times higher odds of sharing data (95% CI: 1.43-1.55) than other funders. USA-based studies were 1.53 times more likely to share data (95% CI: 1.49-1.57) than out of USA. Biological trials were 1.58 times more likely to share data than drug and other trials (95% CI: 1.51-1.66). Phase III trials had the highest odds, 2.47 times, of sharing data (95% CI: 2.38-2.56) than non-Phase III trials.