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Weathering the Impact: ENSO-Driven Disasters, Power Disruption, and Health Outcomes in Medicare Populations

 

Investigators:

Sara Curran, Jeff Stanaway, Luanne Thompson, June Yang, Emmanuela Gakidou

Data sources:

ENSO indices from the National Oceanic and Atmospheric Administration Climate Prediction Center from 1980-2025.

SHELDUS: Special hazard events and losses database for the United States 1970 – 2023. Available by County and day.

Center for Medicare & Medicaid Services claim and beneficiary data from 1990-2023. Available by County and day.

HHS emPOWER: Count of medicare beneficiaries who rely on electricity-dependent durable medical and assistive equipment and devices from 2016-2025. Available by County and month.

DOE-417 archive data: Electric Emergency Incident and Disturbance Report from 2000 to 2023. Available by County and Day.

Spatial Coverage: United States

Temporal Coverage: 2016 – 2023.

Measures:

  • Climate Measurements:

    • ENSO Indices (NOAA): Seasonal measurements of sea surface temperature anomalies used to classify El Niño and La Niña events.
    • SHELDUS: Provides detailed records of natural disaster events (including type, date, and location), allowing alignment of local disasters with ENSO periods. It also includes loss data (e.g., property damage, crop loss, injuries) to quantify event severity.

    Power Infrastructure Measurements:

    • HHS emPOWER Dataset: Monthly, county-level counts of Medicare beneficiaries who rely on electricity-dependent durable medical equipment (DME), indicating vulnerability to power disruptions.
    • DOE OE-417 Archive: Incident-level reports on electrical disturbances, including type of event, date/time, geographic area, and population affected.

    Health Outcomes:

    • CMS Claims and Quality Measures: Data on Medicare beneficiaries covering:
      • Hospital readmission rates
      • Emergency department (ED) and inpatient utilization
      • Home health services
      • Minimum Data Set (MDS) indicators from nursing homes
      • Preventable hospitalizations (e.g., ambulatory care-sensitive conditions)

    Demographic and Socioeconomic Context:

    • County-Level Medicare Population Characteristics: Including race/ethnicity, age, sex, and dual eligibility for Medicare and Medicaid, enabling analysis of differential impacts across vulnerable groups.

Project Summary:

Disruptions driven by the El Niño-Southern Oscillation (ENSO), such as flooding, drought, and extreme temperatures, have long been implicated in public health threats across the United States. For example, during negative phases of ENSO (La Nina events) there is typically an increase in the number of hurricanes that can result in major floods. This also occurs during El Nino events in the Southwest US.  Major floods have been shown to elevate hospitalization rates among older adults for skin conditions, neurological illnesses, musculoskeletal disorders, and injuries in the weeks following exposure (Aggarwal et al. 2025). In addition, other impacts include health care disruptions due to displacement from homes and communities or through damage to health infrastructure. These might be particularly important for those requiring frequent care for chronic illnesses.

However,  mechanisms linking ENSO-related disasters with health outcomes remains poorly understood. For instance, the role of power infrastructure failure, such as prolonged outages disrupting electricity-dependent medical care is a plausible pathway for detrimental impacts on healthcare particularly for the elderly who are less mobile than the general population..

Our U.S.-based project investigates how ENSO-related disasters influence health outcomes among older adults, focusing especially on power disruptions as a critical explanatory pathway. By aligning the data sources mentioned above, we aim to trace if and how power outages amplify the health impact of ENSO-driven disasters on older adults.

We will employ a combination of panel regression models, Difference-in-Difference analysis, and causal mediation analysis to estimate the direct and indirect effects of ENSO-driven disasters, to quantify the role of infrastructure failure and identify populations at higher risk.

Comments

Papers on impacts of El Nino in the U.S. 

Outputs:

Peer-reviewed publications, grant proposals, conference presentations

References:

Aggarwal, Sarika, Jie K. Hu, Jonathan A. Sullivan, Robbie M. Parks, and Rachel C. Nethery. 2025. “Severe Flooding and Cause-Specific Hospitalisation among Older Adults in the USA: A Retrospective Matched Cohort Analysis.” The Lancet Planetary Health 9(7):101268. doi:10.1016/S2542-5196(25)00132-9.


Fussell, Elizabeth, Sara R. Curran, Matthew D. Dunbar, Michael A. Babb, Luanne Thompson, and Jacqueline Meijer-Irons. 2017. “Weather-Related Hazards and Population Change: A Study of Hurricanes and Tropical Storms in the United States, 1980–2012.” The ANNALS of the American Academy of Political and Social Science 669(1):146–67. doi:10.1177/0002716216682942.


Salas, Renee N., Laura G. Burke, Jessica Phelan, Gregory A. Wellenius, E. John Orav, and Ashish K. Jha. 2024. “Impact of Extreme Weather Events on Healthcare Utilization and Mortality in the United States.” Nature Medicine 30(4):1118–26. doi:10.1038/s41591-024-02833-x.