Introduction: In 2017, unprecedented rainfall from Hurricane Harvey resulted in severe flooding in parts of Texas. While the association between the immediate effects of severe weather on mortality is well established, less is known about long-term mortality and how risk may differ across vulnerable populations, especially those reliant on health services. This study examines the association between severe weather exposure from Hurricane Harvey and mortality among vulnerable populations of older adults. Methods: This retrospective cohort study used Medicare administrative claims data from beneficiaries aged 65+ who resided in Texas or Louisiana the year before and after Hurricane Harvey. Historic weather data was used to construct a 4-day measure of ZIP code tabulation area cumulative rainfall and identify locales exposed to high rainfall (above 75mm). Vulnerable older adult populations were identified. Attributable risk and relative risks (RRs) were estimated to quantify the impact of high rain exposure on mortality. Time-to-event analyses estimated associations between exposure to high rain and 12-month mortality. Results: The study included 1,730,693 beneficiaries; 535,794 (37.5%) were exposed to high rain in Texas, and 264,265 (87.5%) in Louisiana. Beneficiaries with Alzheimer’s disease and related dementias (ADRD) exposed to high rain had a 5% higher risk of mortality in fully adjusted models (HR=1.05, 95% CI: 1.02, 1.07) and 1,192 attributable deaths. High rain resulting from Hurricane Harvey was associated with a 13% higher risk of mortality among beneficiaries with end-stage renal disease (ESRD) in fully adjusted models (HR=1.13, 95% CI: 1.04, 1.23) and 85 attributable deaths. Conclusion: The risk of mortality from exposure to severe weather differs based on the type of vulnerability. Those with an ADRD or ESRD diagnosis, in particular, had elevated mortality rates. High rain exposure had a significantly larger mortality impact on those of lower socioeconomic status. Emergency planning should pay particular attention to these highly vulnerable groups.
Bell et al. (Sun,) studied this question.