Temporal trends in mortality and hospitalization related to SARSCOV-2 in dialysis patients in Québec (Canada)

Background: In Canada, Quebec province was the most severely hit region during the first year of the SARS-CoV-2 pandemic. We aimed to compare characteristics and outcomes of dialysis patients during the first and second SARS-CoV-2 transmission surges in this province. Methods: The QRN-COVID-HD study included adult dialysis patients from 13 units in Quebec, with SARS-CoV-2 PCR tests performed between Mar-Sept 2020 (1st wave) and Oct 2020-Feb 2021 (2nd wave). Crude and stratified rates of mortality, hospitalization and intensive care unit (ICU) admission within 90-day of SARS-CoV-2 positivity were calculated with mixed effect Poisson regressions. Adjusted predictors of 90-day outcomes were evaluated using mixed effect logistic regressions and negative binomial regressions (as appropriate). Results: Over this 12-month period, 431 patients were infected with SARS-CoV-2 (211 1st wave;220 2nd wave). Most characteristics (including age) were similar in the two waves although 2nd wave patients were less frequently living in long-term care facilities and had more diabetic nephropathy. Overall, 214 (50%) patients were hospitalized at least once and 214 (26%) died within 90-day of SARS-CoV-2 positivity, with 78% of hospitalizations and 84% of deaths directly attributed to SARS-CoV-2. Mortality and hospitalization rates were lower for 2nd compared to 1st wave patients. Figure In contrast, ICU admissions were similar in both waves (0.14, 95% CI 0.10-0.19 [1st] vs. 0.13, 95% CI 0.09-0.18 [2nd] per 100 pt-yrs). When adjusted for case-mixed differences, the 2nd wave remained associated with lower risk of mortality (OR 0.55, 95% CI 0.32-0.95), hospitalization (OR 0.45, 95%CI 0.28-0.71) and days in hospital (IRR 0.49, 95% CI 0.46-0.53), but similar risk of ICU (OR 0.73;95% CI 0.39-1.37). Conclusions: Dialysis patients with SARS-CoV-2 infections had more favorable clinical outcomes during the 2nd wave, which is consistent with observations in the general population and may be related to improved clinical care.