Geographic proximity to cardiovascular clinical trial sites: A National analysis in the United States

Abstract

Introduction: Suboptimal geographical access to cardiovascular clinical trial sites (CV-CTS) may be a cause of inadequate demographic representation in contemporary trials. Thus, we investigate access to CV-CTS in the US.

Methods: We obtained the location of CV-CTS from Clinicaltrials.gov. We calculated the distance in kilometers from each ZIP code to the nearest CV-CTS, stratifying our results based on urban/rural setting, sex and race.

Results: We identified a total of 10,506 studies in 4,630 US ZIP codes (10.5 %), of those only 237 (5 %) were rural. The overall median CV-CTS distance was 5.8 km (IQR: 2.7, 15.8). For urban residents, this distance was 4.5 km (IQR: 2.3, 9.2), while for rural residents, it was 24.2 km (IQR: 13.8, 42.2).

Results: We revealed important disparities involving geographical proximity to cardiovascular clinical trial sites. Increasing the representation of these populations in clinical trials is paramount to improving the applicability of their findings to real-world settings.

Keywords: Cardiology; Clinical trial sites; Social and environmental determinants of health.

Fig. 1.

A) Map of the distances (in km) of the centroid of the census tracts in the contiguous US to the centroid of the nearest zip code containing a cardiovascular clinical trial site (CV-CTS) B) Distance to nearest CV-CTS stratified by setting and according to sex and race. White = Non-Hispanic White. Black = Non-Hispanic Black. Native = American Indian or Alaska Native. Pacific = Native Hawaiian or Other Pacific Islander.