Susceptibility to heat-related fluid and electrolyte imbalance emergency department visits in Atlanta, GA Open Access

Heidari, Leila Marie (2016)

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Increases in morbidity and mortality from increasing temperatures are some of the most likely primary health impacts of climate change. It is critical to identify potentially susceptible populations to heat morbidity for targeted prevention and more accurate risk assessment. Fluid and electrolyte imbalance (FEI) may provide an especially sensitive and objectively measurable indicator of heat morbidity.


To examine heterogeneity of heat-morbidity associations by determinants of heat vulnerability (sex, race, comorbid congestive heart failure, kidney disease, and diabetes, and neighborhood socioeconomic conditions defined by poverty and education levels), focusing on FEI emergency department (ED) visits, and to explore associations of temperature and FEI ED visits considering a variety of temperature metrics.


A ssociations of warm-season (May-September) same-day temperatures and FEI ED visits were estimated using Poisson generalized linear models allowing for overdispersion; data were from a 20-year daily time series spanning 1993-2012 in Atlanta, GA. Analyses explored associations between all FEI ED visits and different temperature metrics (maximum, minimum, average, and diurnal change in ambient temperature, apparent temperature, and heat index), modeled using linear, quadratic, and cubic terms to allow for non-linear associations. Analyses by strata of determinants of heat vulnerability examined potential heterogeneity of effects for both maximum temperature (TMax) and maximum apparent temperature (ATMax).


Ambient temperature was significantly associated with FEI ED visits regardless of the metric used to define temperature; for example, we found an RR of 1.125 (95% CI: 1.102, 1.150) per interquartile range increase in maximum temperature from the 25th to 75th percentile. Modifier-stratified analyses suggested that risks are great for all populations, but perhaps particularly for males and possibly for nonwhite groups (e.g., Hispanics) and those living in undereducated areas.We found some unanticipated patterns of effect modification in that for the comorbidities, there was a tendency for the 'absent' strata to have stronger associations than 'present' strata, with significant differences observed for comorbid renal disease.


This work highlights the utility of FEI as an indicator of heat morbidity that affects all populations, the health threat posed by warm season temperatures, and considerations regarding assessment of vulnerable populations in heat-health research .

Table of Contents

A. Introduction 1

B. Methods 6

C. Results 9

D. Discussion 11

E. References 20

F. Appendix: Tables and Figures 26

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