Drought and the risk of hospital admissions and mortality in older adults in the western USA from 2000 to 2013: a retrospective study

摘要

Occurrence, severity and geographic extent of droughts are anticipated to increase under climate change, but the health consequences of drought are unknown. For counties in the western U.S. (N=618) and for the period 2000 to 2013, we use data from the U.S. Drought Monitor to identify: 1) full drought periods; 2) non-drought periods; and 3) worsening drought periods stratified by low- and high-severity. We use Medicare claims to calculate daily rates of cardiovascular-related hospital admissions, respiratory-related admissions, and deaths among adults 65 years or older. Using a two-stage hierarchical model, we estimated the percentage change in health risks when comparing drought to non-drought period days controlling for daily weather and seasonal trends. On average there were 2.1 million days and 0.6 million days classified as non-drought periods and drought periods, respectively. Compared to non-drought periods, respiratory admissions significantly decreased by -1.99% (95% posterior interval (PI): -3.56, -0.38) during the full drought period, but not during worsening drought conditions. Mortality risk significantly increased by 1.55% (95% PI: 0.17, 2.95) during the high-severity worsening drought period, but not the full drought period. Cardiovascular admissions did not differ significantly during either full drought or worsening drought periods. In counties that experienced fewer drought events, we found risks for cardiovascular disease and mortality to significantly increase during worsening drought conditions. This research describes an understudied environmental association with both regional and global health significance.