Association between heat stroke and ischemic heart disease: A national longitudinal cohort study in Taiwan

The purpose of this study is to determine the relationship between heat stroke and ischemic heart disease (IHD), in a nationwide population using a longitudinal approach. We retrospectively examined the data from the National Health Insurance Research Database (NHIRD) in Taiwan, for patients examined between 2000 and 2013. In total, 628 patients with a heat stroke episode were enrolled and matched with 1256 patients without any history of a heat stroke episode by propensity score matching at a ratio of 1:2. The mean follow-up years of the heat stroke group was 11.89 years and the mean follow up of the control group was 11.51 years. An association between heat stroke episodes and IHD (log-rank p <.001) was found in a univariate cox regression analysis. After multivariate adjustment, age, comorbidities (hypertension, diabetes, stroke), and lower insurance premiums were associated with IHD events in patients who had a heat stroke. IHD was independently associated with heat stroke following cox multivariate regression analysis and patients with a heat stroke episode had a higher incidence of IHD events compared to those without any heat stroke episode (2598.41/10⁵ person-years vs. 1286.14/10⁵ person-years, adjusted hazard ratio 3.527, 95% CI: 2.078–4.032, p <.001). The onset of IHD in patients who suffered a heat stroke was earlier than in those without a heat stroke episode (2.08 ± 3.45 vs. 3.61 ± 3.25 years, p <.001). In conclusion, clinicians should be aware about evaluating the IHD risk following a heat stroke episode in a patient.