The impact of COVID-19 on all-cause mortality and life expectancy: findings from a population-based cohort in uMkhanyakude district, northern KwaZulu-natal

BACKGROUND: Despite the comprehensive death reporting system in South Africa, significant gaps persist in our understanding of the pandemic's impact in rural areas. METHODS: We computed monthly death counts stratified by demographic factors from a population-based demographic surveillance cohort in rural KwaZulu-Natal. We fit seasonally adjusted negative binomial regression models to estimate excess mortality during the COVID-19 pandemic period (5 March 2020 to 31 December 2021) compared to the pre-pandemic period (1 January 2015 to 4 March 2020). We then assessed the relative risk of death by health and sociodemographic factors and considering apotential interaction with the COVID-19 pandemic. Finally, we calculated changes in life expectancy at the age of 15 and conducted a decomposition analysis to identify life expectancy changes by age group. RESULTS: We observed two major periods of excess mortality during the beta and delta waves of the COVID-19 pandemic, respectively. During the pre-pandemic period, people with HIV (PWH) had slightly higher mortality rates (RR = 1.8; 95%CI 1.3 - 2.4) than their HIV-negative counterparts. This excess risk reduced during the COVID-19 period (HIV RR = 1.5; 95%CI 1.2 - 2.0). Similar patterns were noted for individuals with diabetes (pre-pandemic RR = 1.6; 95%CI 1.2 - 2.2 vs during COVID-19 RR = 1.4; 95%CI 1.1 - 1.9). In contrast, individuals with hypertension experienced a 15% relative increase death rate during the pandemic compared to pre-COVID period (p-interaction = 0.003). Similarly, hypertensive PWH had significantly elevated mortality risks during COVID-19 (RR = 2.18; 95% CI: 1.45-3.26, p < 0.001). Throughout the study, women consistently had higher life expectancy at age 15 than men. However, women contributed more to pandemic-related life expectancy reductions, along with specific age and health groups. CONCLUSION: We found contrasting impacts of co-morbidities on mortality during the COVID-19 pandemic in rural South Africa, and that reductions in life expectancy at age 15 were greater in women than men. These findings emphasize the critical need to consider specific needs of rural populations, and tailor public health strategies that prioritize vulnerable populations and address health inequities to mitigate the effects of pandemics in low-resource settings.