Effects of extreme climate events on the morbidity of a sample of medical scheme lives in South Africa

Abstract

Climate change is intensifying the frequency and severity of extreme weather events, with profound implications for human health. While evidence on mortality impacts is emerging, the morbidity effects of extreme climate events in South Africa remain less explored, particularly within the insured population. This study investigates the morbidity impacts of extreme temperature events on a sample of medical scheme members across South Africa. Using health claims data for approximately 3.48 million beneficiaries, representing close to 40% of the South African private medical scheme market, over the period 2014–2024 (excluding COVID-19 years), linked with regional temperature data,, this study analyses daily healthcare utilisation patterns across all nine provinces. Two methods are applied: two-dimensional kernel density estimation to explore non-linear associations between temperature extremes and utilisation, and distributed lag non-linear models with multivariate meta-regression to capture lagged effects up to 21 days. Results generally reveal a U-shaped relationship between temperature extremes and healthcare utilisation. Extreme heat is associated with increases in healthcare visits and admissions, particularly for circulatory, endocrine, nephrology, and trauma-related conditions, with the strongest effects observed among members aged 40 and older. Extreme cold is linked to elevated respiratory-related utilisation, with lagged impacts persisting several days post-exposure. A case study of the April 2022 KwaZulu-Natal floods, using precipitation data, shows a sharp decline in healthcare visits and admissions during peak rainfall, reflecting acute disruption to healthcare access and utilisation, followed by a partial rebound as weather conditions normalise. These findings align with international evidence while providing novel South African insights, highlighting the vulnerability of South Africa’s people and the healthcare system itself to extreme climate events. The results underscore the importance of integrating climate-related health risks into actuarial applications. Future research can extend this analysis to the broader population and to other climate-related hazards, including air pollution and drought.