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. 2015 Mar 5;10(3):e0118958.
doi: 10.1371/journal.pone.0118958. eCollection 2015.

Identifying individual risk factors and documenting the pattern of heat-related illness through analyses of hospitalization and patterns of household cooling

Michael T Schmeltz  1 , Grace Sembajwe  2 , Peter J Marcotullio  3 , Jean A Grassman  4 , David U Himmelstein  2 , Stephanie Woolhandler  2
Affiliations

Identifying individual risk factors and documenting the pattern of heat-related illness through analyses of hospitalization and patterns of household cooling

Michael T Schmeltz et al. PLoS One. .

Abstract

Background: As climate change increases the frequency and intensity of extreme heat events researchers and public health officials must work towards understanding the causes and outcomes of heat-related morbidity and mortality. While there have been many studies on both heat-related illness (HRI), there are fewer on heat-related morbidity than on heat-related mortality.

Objective: To identify individual and environmental risk factors for hospitalizations and document patterns of household cooling.

Methods: We performed a pooled cross-sectional analysis of secondary U.S. data, the Nationwide Inpatient Sample. Risk ratios were calculated from multivariable models to identify risk factors for hospitalizations. Hierarchical modeling was also employed to identify relationships between individual and hospital level predictors of hospitalizations. Patterns of air conditioning use were analyzed among the vulnerable populations identified.

Results: Hospitalizations due to HRI increased over the study period compared to all other hospitalizations. Populations at elevated risk for HRI hospitalization were blacks, males and all age groups above the age of 40. Those living in zip-codes in the lowest income quartile and the uninsured were also at an increased risk. Hospitalizations for HRI in rural and small urban clusters were elevated, compared to urban areas.

Conclusions: Risk factors for HRI include age greater than 40, male gender and hospitalization in rural areas or small urban clusters. Our analysis also revealed an increasing pattern of HRI hospitalizations over time and decreased association between common comorbidities and heat illnesses which may be indicative of underreporting.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Heat-Related Illness versus All Hospitalizations Rates, Summer 2001–2010.
The dotted line represents the rate of all hospitalizations during the study time period which remained approximately level over time. The solid line represents heat-related illness hospitalizations which although varied by year have steadily increased over the study period.
See this image and copyright information in PMC

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