Warm season temperatures and emergency department visits in Atlanta, Georgia

Abstract

Purpose Extreme heat events will likely increase in frequency with climate change. Heat-related health effects are better documented among the elderly than among younger age groups. We assessed associations between warm-season ambient temperature and emergency department (ED) visits across ages in Atlanta during 1993-2012. Methods We examined daily counts of ED visits with primary diagnoses of heat illness, fluid/electrolyte imbalances, renal disease, cardiorespiratory diseases, and intestinal infections by age group (0-4, 5-18, 19-64, 65+ years) in relation to daily maximum temperature (TMX) using Poisson time series models that included cubic terms for TMX at single-day lags of 0-6 days, controlling for maximum dew-point temperature, time trends, week day, holidays, and hospital participation periods. We estimated rate ratios (RRs) and 95% confidence intervals (CI) for TMX changes from 27 °C to 32 °C (25th to 75th percentile) and conducted extensive sensitivity analyses. Results We observed associations between TMX and ED visits for all internal causes, heat illness, fluid/electrolyte imbalances, renal diseases, asthma/wheeze, diabetes, and intestinal infections. Age groups with the strongest observed associations were 65+ years for all internal causes [lag 0 RR (CI)=1.022 (1.016-1.028)] and diabetes [lag 0 RR=1.050 (1.008-1.095)]; 19-64 years for fluid/electrolyte imbalances [lag 0 RR=1.170 (1.136-1.205)] and renal disease [lag 1 RR=1.082 (1.065-1.099)]; and 5-18 years for asthma/wheeze [lag 2 RR=1.059 (1.030-1.088)] and intestinal infections [lag 1 RR=1.120 (1.041-1.205)]. Conclusions Varying strengths of associations between TMX and ED visits by age suggest that optimal interventions and health-impact projections would account for varying heat health impacts across ages.

Susceptibility to Heat-Related Fluid and Electrolyte Imbalance Emergency Department Visits in Atlanta, Georgia, USA

“…Emergency department visit data for 20-county Atlanta, Georgia spanning the period 1 January 1993 to 31 December 2012 were previously collected for the Studies of Particles and Health in Atlanta [22,41,42,43,44,45,46]. Briefly, data on ED visits to hospitals in the Atlanta metropolitan area were obtained from individual hospitals (for the period 1993–2004) and from the Georgia Hospital Association (for the period 2005–2012).…”

“…Analyses were conducted for each strata of interest to examine the heterogeneity of effects by potential determinants of heat susceptibility with daily maximum temperature (TMax) and daily maximum apparent temperature (ATMax). In all analyses, temperature metrics were modeled using linear, quadratic, and cubic terms to allow for possible nonlinear relationships with FEI ED counts [22]. All analyses considered same day (lag 0) temperatures, as this lag showed the strongest associations with FEI in our previous work [22].…”

“…Despite being under explored, FEI morbidity has shown strong associations with high heat in Atlanta, Georgia [22] and California [10,11,12], and it has properties that make it a useful indicator of heat morbidity: (1) a diagnosis of FEI suggests general dehydration [23] and is made based on specific measurable conditions such as: hyperosmolality and/or hypernatremia, acidosis, alkalosis, mixed acid-base balance disorder, volume depletion (includes dehydration), fluid overload, hyperpotassemia, hypopotassemia, and other electrolyte and fluid disorders (e.g., electrolyte imbalance, hyperchloremia, and hypochloremia) [24]; and (2) the presence of FEI can be established relatively quickly and objectively through laboratory measurements combined with a physical examination and an assessment of the patient′s clinical history [25]. …”

“…For example, some patient populations, such as those with congestive heart failure [34,35], myocardial infarctions [36,37], renal failure [38], and diabetes mellitus [39], are especially prone to FEI. Furthermore, medical visits for these types of conditions have been found to be associated with heat [8,11,12,15,22,40]. While FEI may be a pathway for increased susceptibility to heat for patients with these co-morbidities, to our knowledge, no previous studies have examined this question.…”

“…Previous work in Atlanta found strong associations between warm-season same-day maximum temperature and maximum apparent temperature and FEI ED visits, with the strongest effects observed among patients in the 19–64 year old age group [22]. The present study expands on this analysis by estimating associations between heat and FEI morbidity among all ages for a variety of additional temperature exposure metrics (maximum, minimum, average, and diurnal change in ambient air temperature, apparent temperature, and heat index) and by examining heterogeneity of heat-morbidity associations by potential determinants of heat susceptibility (sex, race, comorbid congestive heart failure, kidney disease, and diabetes diagnoses, and neighborhood socioeconomic conditions).…”