Direct and indirect effects of the COVID-19 pandemic on mortality: an individual-level population-scale analysis using linked electronic health records, Wales, United Kingdom, 2016 to 2022

BackgroundThe COVID-19 pandemic resulted in increased mortality directly and indirectly associated with COVID-19.AimTo assess the impact of the COVID-19 pandemic on all-cause and disease-specific mortality and explore potential health inequalities associated with area-level deprivation in Wales.MethodsTwo population-based cohort studies were derived from multi-sourced, linked demographic, administrative and electronic health record data from 2016 to 2019 (n = 3,113,319) and 2020 to 2022 (n = 3,571,471). Data were analysed using generalised linear models adjusting for age, sex, area-level deprivation and time at risk.ResultsCOVID-19 deaths peaked in January 2021 (54.9/100,000 person-months, 95% confidence interval (CI): 52.4-57.5). The pandemic indirectly affected deaths, with higher than expected maximum relative mortality rates (RR) related to cancer (RR: 1.24, 95% CI: 1.13-1.36), infectious diseases (excluding respiratory infections) (RR: 2.09, 95% CI: 1.27- 3.43), circulatory system (RR: 1.41, 95% CI: 1.28-1.56), trauma (RR: 2.04, 95% CI: 1.57- 2.65), digestive system (RR: 1.54, 95% CI: 1.25-1.91), nervous system (RR: 1.63; 95% CI: 1.34-2.00) and mental and behavioural disorders (RR: 1.85, 95% CI: 1.58-2.16). Mortality associated with respiratory diseases (unrelated to COVID-19) were lower than expected (minimum RR: 0.52, 95% CI: 0.45-0.60). All-cause mortality was lower in least deprived communities compared with most deprived (RR: 0.61, 95% CI: 0.60-0.62), and the magnitude of this effect increased during the pandemic.ConclusionsAll-cause and disease-specific mortality directly and indirectly associated with COVID-19 increased during the COVID-19 pandemic. Socioeconomic disparities were exacerbated during this time.