Health technology assessment (HTA) informs healthcare policy, reimbursement, and clinical decision making. Transparency in conflict-of-interest (CoI) reporting is critical to ensure the credibility and impartiality of HTA outputs. However, the extent and consistency of CoI disclosures across HTA reports remain unclear.

To systematically assess the frequency, form, and comprehensiveness of CoI reporting in published HTA reports and to identify possible patterns.

We retrieved and screened 1,215 HTA records from the International HTA Database. After exclusions, 689 English-language reports were analyzed (full and mini HTAs (n = 254), rapid reviews (n = 166), and HTA research studies (n = 269)). CoI statements were categorized as positive (declared CoI) or negative (no CoI). Cross-country comparisons and content analyses of positive statements were conducted distinguishing between the presence of disclosure, its content and granularity, and the transparency of conflict management.

CoI statements were present in 71 percent of full/mini HTAs, 60 percent of rapid reviews, and 100 percent of HTA research studies. CoIs were declared in 14, 16, and 83 percent of these categories, respectively. Reporting practices varied widely among agencies, with few providing detailed or standardized disclosures. Financial CoI dominated, while nonfinancial and institutional CoI were less frequently addressed.

CoI reporting in HTA remains inconsistent despite its recognized importance for transparency. Disclosure and management of conflicts represent distinct governance functions, both requiring attention. Our findings highlight a need for harmonized, individual-level disclosure policies, and a description of CoI management strategies in HTA processes.