Coauthor Country Affiliations in International Collaborative Research Funded by the US National Institutes of Health, 2009 to 2017

IMPORTANCE: The US National Institutes of Health (NIH) is the largest funder of biomedical and behavioral research in the world. International collaborative research—a subset of NIH’s portfolio—is critical to furthering the agency’s health research mission. OBJECTIVE: To quantify the extent of the NIH’s international collaborations and the relative importance of this research through the lens of publications. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used bibliometric data from the Web of Science database to analyze trends in the growth of NIH-funded publications from January 1, 2009, to December 31, 2017, and examined their importance using national affiliations of all coauthors listed, h indices, and citation impact scores. All countries with coauthor affiliations in NIH-funded publications during the study period were included. Data were analyzed from October 22 through November 16, 2018. EXPOSURES: Country affiliations of coauthors’ institutions in NIH-funded publications indexed in the Web of Science database from 2009 to 2017. MAIN OUTCOMES AND MEASURES: Trends in the number of NIH-supported publications with non-US coauthors during a 9-year period and their relative importance assessed by h index per country and category-normalized citation impact (CNCI) for groups of country affiliations in 2017. RESULTS: From 2009 to 2017, the annual count of NIH-funded publications increased 46.2% from 67 041 to 98 002. This increase was driven in part by an increase in publications with a non-US author alone or as a collaborator with a US author compared with those exclusively with US authors, reflected by an increase in the percentage of publications with non-US coauthors from 28.3% to 34.8%. Moreover, in 2017, publications coauthored by US-affiliated and non–US-affiliated investigators had a higher mean CNCI (1.99) than those whose authors were only US affiliated (1.54) or non–US affiliated (1.35). China became the most frequent publishing partner, with 6982 coauthored publications and the greatest increase over time among non-US countries. CONCLUSIONS AND RELEVANCE: In a 9-year period when the NIH budget remained relatively unchanged, an increase in the number of publications occurred with a growing trend toward more international collaborations of authorship; these publications also had a higher CNCI than publications with only US or only non-US authors. The findings suggest that international collaboration is a vital and growing component of the NIH’s research output and likely reflects increased globalization of biomedical research.