The impact of COVID-19 infection before the vaccination era on the hospitalized patients requiring hemodialysis: a single-center retrospective cohort

Due to effective vaccinations, the COVID-19 (coronavirus disease 2019) infection that caused the pandemic has a milder clinical course. We aimed to assess the mortality of hospitalized COVID-19 patients before the vaccination era. We investigated the mortality in those patients between 1 October 2020 and 31 May 2021 who received hemodialysis treatment [patients with previously normal renal function (nCKD), patients with chronic kidney disease previously not requiring hemodialysis (CKDnonHD), chronic kidney disease (CKD), and patients on regular hemodialysis (pHD)]. In addition, participants were followed up for all-cause mortality in the National Health Service database until 1 December 2021. In our center, 83 of 108 (76.9%) were included in the analysis due to missing covariates. Over a median of 26 (interquartile range 11-266) days of follow-up, 20 of 22 (90.9%) of nCKD, 23 of 24 (95.8%) of CKDnonHD, and 17 of 37 (45.9%) pHD patients died (p < 0.001). In general, patients with nCKD had fewer comorbidities but more severe presentations. In contrast, the patients with pHD had the least severe symptoms (p < 0.001). In a model adjusted for independent predictors of all-cause mortality (C-reactive protein and serum albumin), CKDnonHD patients had increased mortality [hazard ratio (HR) 1.91, 95% confidence interval (CI), 1.02-3.60], while pHD patients had decreased mortality (HR 0.41, 95% CI 0.20-0.81) compared to nCKD patients. After further adjustment for the need for intensive care, the difference in mortality between the nCKD and pHD groups became non-significant. Despite the limitations of our study, it seems that the survival of previously hemodialysis patients was significantly better.