Heat-related cardiovascular morbidity and mortality in Switzerland: a clinical perspective

Abstract

Summary AIMS: Previous studies found increased cardiovascular mortality during hot days, while emergency hospital admissions were decreasing. We explored potential underlying reasons by analysing clinically similar cardiovascular disease groups taking into account primary, underlying and immediate causes of death. METHODS AND RESULTS: We assessed associations of daytime maximum temperature in relation to cardiovascular deaths and emergency hospital admissions between 1998 and 2016 in Switzerland. We applied conditional quasi-Poisson models with non-linear distributed lag functions to estimate relative risks (RRs) of daily cardiovascular mortality and morbidity for temperature increases from the median (22 °C) to the 98th percentile (32 °C) of the warm season temperature distribution with 10 days of lag. Cardiovascular mortality (n = 163,856) increased for total cardiovascular disease (RR 1.13, 95% confidence interval [CI] 1.08–1.19) and the disease groups hypertension (1.18, 1.02–1.38), arrhythmia (1.29, 1.08–1.55), heart failure (1.22, 1.05–1.43) and stroke of unknown origin (1.20, 1.02–1.4). In contrast, emergency hospital admissions (n = 447,577) decreased for total cardiovascular disease (0.91, 0.88–0.94), hypertension (0.72, 0.64–0.81), heart failure (0.83, 0.76–0.9) and myocardial infarction (0.88, 0.82–0.95). Opposing heat effects were most pronounced for disease groups associated with diuretic and antihypertensive drug use, with the age group ≥75 years at highest risk. CONCLUSIONS: Volume depletion and vasodilation from heat stress plausibly explain the risk reduction of heat-related emergency hospital admissions for hypertension and heart failure. Since primary cause of death mostly refers to the underlying chronic disease, the seemingly paradoxical heat-related mortality increase can plausibly be explained by an exacerbation of heat effects by antihypertensive and diuretic drugs. Clinical guidelines should consider recommending strict therapy monitoring of such medication during heatwaves, particularly in the elderly.

Non-optimal apparent temperature and cardiovascular mortality: the association in Puducherry, India between 2011 and 2020

“…The findings from our cause-specific analysis compare to a recent study by Schulte et al ., in Switzerland which found limited risks of mortality from myocardial infarction (part of IHD in our study) associated with temperature [ 49 ]. They also found the risk of mortality from strokes (CVA in our study) increases with heat.…”

Associations Between Extreme Temperatures and Cardiovascular Cause-Specific Mortality: Results From 27 Countries

“… 42 In patients with heart failure who receive diuretics, heat may result in severe volume depletion and potentially, shock. 43 On the other hand, cold exposure leads to increased sympathetic activity that vasoconstricts skin and increases skeletal muscle tone to generate and conserve heat. This leads to catecholamine-driven rise in blood pressure (mainly through an increase in peripheral vascular resistant), and hence, increased cardiac oxygen demand to overcome this increase in afterload.…”

Swiss Cohort & Biobank – The White Paper

“…Molecular characterizations need to complement, and be complemented with, repeated structural and psychosocial characterization at individual and macro-level [48], such as evidenced by the repeated deep characterization of participants of the ABCD study investigating the brain and cognitive development of adolescents. 13 The greater integration of psychosocial factors and sociological expertise has been advocated to shape the development of exposome studies. This is critical to assure that multi-omics signals of limited size and public health relevance do not get more weight than the recognition of overarching factors underlying health disparities, which are often unrecognized or not deemed modifiable in public health strategies (e.g., economic and socio-economic marginalization) [42,51].…”

“…Global warming is an environmental threat of unprecedented dimension in need of both global and local socially acceptable solutions. Heat waves have a direct acute adverse effect on human health and wellbeing [10][11][12][13]. The direct long-term health and wellbeing effects still remain rather poorly understood.…”