Flooding is the most significant environmental disaster worldwide, accounting for 40% of all natural disasters and causing half of all natural disaster-related fatalities. Over the past century, heavy rainfall has become more frequent and intense, increasing the risk of flooding due to climate change. The health effects of flooding surface as multiple risks, including drowning, injuries that stem from objects and toxic substances, electrical accidents, and exposure to extreme cold.
The destruction of infrastructure produces water contamination, along with disease proliferation, healthcare breakdown, and population relocation. Flooding can cause permanent health complications, worsening preexisting medical conditions and mental health issues. Every individual faces different outcomes when affected by flooding. The population subgroups who experience the worst health outcomes during floods consist of women, children, and the elderly, while young males face the highest threat of death.
The research examined emergency department (ED) treatments and unplanned hospital admissions for Medicare beneficiaries aged 65 or older who resided in regions affected by significant flooding from January 1, 2008, to December 31, 2017. The investigation took place from April 3 through December 15, 2023. The researchers conducted their study according to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) protocols.
Conditional fixed-effects regression served as an analytical method to evaluate any changes in ED visits together with hospitalizations during both pre- and post-flood periods. The researchers analyzed incident rate ratios together with their corresponding 95% confidence intervals (Cls). Risk percentages and estimates of additional visits following the floods were calculated as part of this research. The study conducted additional analyses to evaluate whether selected factors had any impact on the data. Independent investigators analyzed the healthcare expenses related to flood-related consequences and adjusted them to 2017 U.S. dollars.
Among 11801527 Medicare beneficiaries aged 65 and older (average age 74.4 years; 56.3% female), the rate of all-cause emergency department (ED) visits increased by 4.8% (IRR, 1.05; 95% CI, 1.04-1.05), and hospitalizations increased by 7.4% (IRR, 1.07; 95% CI, 1.07-1.08) following exposure to a flood.
The mean ED visit cost per ZCTA was $3,230 (95% CI, $3,198-$3,261), and the mean cost for hospitalizations was $11,310 (95% CI, $11,252-$11,367). The estimated overall national cost to the Medicare system was $69,275,429 (95% CI, $63,010,840-$76,315,210) for ED visits and $191,409,579 (95% CI, $172,782,870-$206,181,300) for hospitalizations.
Additional analysis indicated that some populations, such as adults aged more than 85 years and specific seasons, suffered more from flooding.
The research examined the impact of floods on older adults using national Medicare claims combined with flooding information. Following major flooding incidents, the affected communities experienced an increase in emergency department visits by 4.8% and hospital admission rates rising by 7.4%. In the 10-year study period, the analyzed floods caused Medicare beneficiaries to visit ED facilities 21,265 more times and 16,787 additional hospitalizations, resulting in healthcare expenses reaching $260 million in total.
The research analysis reveals that widespread flooding episodes lead to higher healthcare demands and cost expenditures among the senior American population. The observed excessive emergency department usage, along with hospitalizations, particularly affects elderly adults, underscores the requirement for directed public health responses and better emergency readiness programs. The programs should work toward decreasing health disparities that result from flooding.
The apparent high costs of such environmental disasters demonstrate the substantial rise in future healthcare expenditures if climate change mitigation efforts are insufficient. This research shows that calculations of disaster expenses that fail to include medical expenses and mortality costs are likely inaccurate in their present form. This study delivers essential insights about flood-related health effects yet emphasizes the need for further research due to an aging population and worsening climate trends.
References: Wettstein ZS, Parrish C, Sabbatini AK, et al. Emergency care, hospitalization rates, and floods. JAMA Netw Open. 2025;8(3):e250371. doi:10.1001/jamanetworkopen.2025.0371
