A quantitative analysis of global AI medical studies: gaps in randomized controlled trials

Medical artificial intelligence (AI) has advanced rapidly, yet a comprehensive quantitative overview of its clinical evaluation landscape remains lacking. We conducted a scoping review of 218 systematic reviews published between September 2023 and September 2024, from which 4667 primary studies were identified and classified by research stage, geography, specialty, and study design. Most studies were preclinical (88.2%, 4114/4667), while only 2.4% (113/4667) were randomized controlled trials (RCTs). Research was highly geographically concentrated: the top 10 contributing countries accounted for 75.5% of total country contributions, of which the United States and China contributed 47.5%. Among all primary studies, neoplasms (32.5%, 1518/4667) and musculoskeletal disorders (14.1%, 656/4667) were the most common, whereas digestive (38.1%, 43/113) and circulatory diseases (12.4%, 14/113) accounted for most RCTs. Among RCTs, 67.3% (76/113) were single-center, and 71.7% (81/113) did not report adherence to any reporting guideline. Overall, 82.3% (93/113) of RCTs reported favorable outcomes, although methodological concerns were common, particularly in allocation concealment and blinding. These findings indicate that medical AI research remains heavily skewed toward early-stage development, with limited high-quality clinical evidence. Strengthening trial design, multicenter collaboration, and reporting transparency will be critical to support the safe and equitable integration of AI into clinical practice.