Trends in NHLBI-Funded Research on Sex Differences in Hypertension.

Although sex differences in blood pressure levels and the prevalence of hypertension are well recognized, the mechanisms responsible for this sexual dimorphism remain poorly understood. To gain a better understanding of the research funding trends in the field of sex differences related to hypertension and the main research topics funded by the National Heart, Lung, and Blood Institute (NHLBI), we analyzed the entire NHLBI award portfolio between fiscal years (FYs) 1991 to 2014. Using specific search terms to define “sex differences,” we interrogated the publicly available list of NHLBI-funded awards active in FY1991 to FY2014 in the National Institutes of Health (NIH) Research Portfolio Online Reporting (RePORTER) database. We further analyzed and categorized awards according to a disease focus and whether each award was directly focused on comparing males versus females, or examining the effects of sex hormones in either sex. The number of NHLBI awards related to “sex differences in hypertension” progressively increased from FY1991 to FY2014, for a cumulative total of 486 awards during the entire period analyzed. The overall dollar investment has also progressively increased from $0.5 million (FY1991) to $18.3 million (FY2014), for a cumulative total of $187 million during FY1991 to FY2014. When compared with global funding trends, NHLBI seems to be the largest funder of research on “sex differences in hypertension” in the world. Importantly, the increased NHLBI investment in sex differences in hypertension research has enabled the investigation of an increased diversity of scientific topics. Although NHLBI is funding an increasing number of awards related to “sex differences in hypertension,” there are still many unanswered questions related to the mechanisms underlying this disparity.