Introduction The U.S. Preventive Services Task Force (USPSTF) issues “Insufficient Evidence” (I) statements when scientific evidence is inadequate for making recommendations about clinical preventive services. Insufficient Evidence statements may be changed to definitive recommendations if new research closes evidence gaps. This study examines the characteristics of evidence that informed changes from I statements to definitive recommendations, including NIH's role as a funder. Methods A total of 11 USPSTF Insufficient Evidence statements that were changed between 2010 and 2019 were assessed. Study designs, bibliometric influence, and funding sources for scientific articles cited in USPSTF evidence reviews were characterized for each I statement. Data were analyzed in 2019–2020. Results Most I statements (82%) changed to a B grade; an average of 8.4 years elapsed between issuing the I statement and releasing the definitive recommendation. An average of 63 (range=19−253) articles were included in each USPSTF evidence review. NIH support was cited in 28.8% of articles, on average. The proportion of NIH-funded articles reporting RCT designs was similar to that of non–NIH-funded articles (64.5% vs 59.5%). A higher proportion of NIH-funded articles were rated good quality for study design (39.0%) than the proportion of non–NIH-funded articles (24.4%). Bibliometric influence measured by relative citation ratios was higher for NIH-funded (mean=14.78) than for non–NIH-funded (mean=5.07) articles. Conclusions Study designs and funding supports varied widely across topics, but overall, NIH was the largest single funder of evidence informing 11 changed USPSTF I statements. Enhanced efforts by NIH and other stakeholders to address I statement evidence gaps are needed.
