Mortality associated with the COVID-19 pandemic in the Swiss dialysis population beyond SARS-CoV-2 infection

Background. While SARS-CoV-2 infection has direct obvious consequences on patients undergoing dialysis, the COVID-19 pandemic also had an indirect impact on health systems. Therefore, we aimed to determine whether the COVID-19 era itself was associated with adverse consequences in the Swiss dialysis population as compared to the pre-COVID-19 era, while accounting for direct impact of SARS-CoV-2 infection. Methods. We retrospectively included all patients recorded in the Swiss dialysis registry from January 2014 to December 2022. The pre-COVID-19 era and the COVID-19 era were defined based on the cut-off date of January 2020. Cox proportional hazard model was used with all-cause mortality as the primary outcome. Results. The cohort consisted of 7837 patients from 97 dialysis centres. Median age was 68.6 years with 66.1% men. Crude mortality rates were 11.6% (11.0% to 12.2%) and 14.2% (13.4% to 14.9%) person-years for the pre-COVID-19 era and the COVID-19 era, respectively. In multivariable analysis, SARS-CoV-2 infection was associated with an increased risk of mortality (HR 4.26, 95% CI 3.65 to 4.97, P < .001) while the COVID-19 era itself was not (HR 0.98, 95% CI 0.88 to 1.08, P = .687). Conclusions. The COVID-19 era was not associated with an excess of mortality in the Swiss dialysis population as compared to the pre-COVID-19 era when accounting for the direct effect of SARS-CoV-2 infection. This suggests that control measures established during the pandemic did not have a negative impact on dialysis patients at the national level. These results could inform health policy makers in the eventuality of future pandemics.