Generalizability of Heat-Related Health Risk Associations Observed in a Large Healthcare Claims Database of Patients with Commercial Health Insurance
Extremely hot days are unambiguously associated with higher risk of illness and death, and consequently with increased hospital admissions for a range of diagnoses.
Extreme ambient heat is associated with higher risk of illness and death. Databases of medical claims from US-based patients with commercial or Medicare Advantage health insurance, have been used to quantify the health impacts of heat. Whether results for the insured sub-population generalize to the broader (insured + uninsured) population is an open question that we address using data on the universe of California hospital visits from 2012 to 2019. We examined changes in daily rates of emergency department (ED) encounters of various causes among patients in a commercially insured population and the broader population in California, US. We defined extreme heat exposure as any day in a group of 2 or more days with maximum temperatures exceeding the county-specific 97.5th percentile and used a space-time-stratified case-crossover design to assess and compare the impacts of heat on health.
While average incidence rates of medical encounters differed by dataset, rate ratios for ED encounters were similar across datasets for all causes (ratio of incidence rate ratios, rIRR = 0.989; 95% confidence interval, CI = [0.973, 1.011]), heat-related causes (rIRR = 1.080; 95% CI = [0.999, 1.168]), renal disease (rIRR = 0.963; 95% CI = [0.718, 1.292]), and mental health disorders (rIRR = 1.098; 95% CI = [1.004, 1.201]). Rate ratios for inpatient encounters were also similar. Results suggest that medical claims data can serve a valid resource for estimating the health impacts of extreme heat.
Extreme ambient heat is unambiguously associated with higher risk of illness and death. The Optum Labs Data Warehouse (OLDW), a database of medical claims from US-based patients with commercial or Medicare Advantage health insurance, has been used to quantify heat-related health impacts. Whether results for the insured sub-population are generalizable to the broader population has to our knowledge not been documented. We sought to address this question, for the US population in California from 2012 to 2019. We defined extreme heat exposure as any day in a group of 2 or more days with maximum temperatures exceeding the county-specific 97.5th percentile and used a space-time-stratified case-crossover design to assess and compare the impacts of heat on health. This work presents evidence that OLDW can continue to be a resource for estimating the health impacts of extreme heat.