INCIDENCE AND OUTCOME OF SARS-COV-2 INFECTION IN THE POPULATION UNDERGOING DIALYSIS TREATMENT IN LAZIO REGION

Abstract Background and Aims Patients with chronic kidney disease (CKD) represent a frail population with severe co-morbidities and different degrees of immune dysfunction. These patients might be at higher risk of SARS-CoV-2 infection and might experience severe consequences of COVID-19. In March 2020, the Lazio Regional Dialysis and Transplantation Registry (LRDTR) implemented a questionnaire to obtain information on dialysis patients who have developed SARS-CoV-2 infection. The aims of this study is to evaluate the incidence and the short-term lethality of SARS-CoV-2 infection in the population undergoing dialysis treatment in Lazio Region. Method A cohort of patients treated in the dialysis units of Lazio Region was enrolled. Prevalent dialysis patients at 1/1/2020 and incident patients during the period 01/01/2020-08/01/2020 were included. The LRDTR collects information on dialysis patients from the start of chronic dialysis treatments with biannual update and immediately informing about the end of dialytic treatment (death, renal transplant, etc). Infection was traced in the LRDTR from March 2020 to 08/13/2020. The information on vital status was obtained from LRDTR and the mortality Lazio registry up to 10/30/2020. Poisson models, crude and adjusted for sex and age, were used to estimate incident rate of infection and mortality rate on dialysis patients and on dialysis patients who have developed SARS-CoV-2 infection, and respective confidence intervals of 95% (CI95%). Results During the study period, the estimate of the number of patients undergoing dialysis treatment was 5196 in Lazio Region, 65% were males with mean age of 70 years. Thirty-seven patients were infected with SARS-CoV-2: 70% males, mean age 73 years. These patients were treated in 24 different dialysis units. The cumulative incidence rate of SARS-CoV-2 infection was 0.71% (95% CI 0.52-0.98) and the adjusted incidence rate was 3.3 *100,000 Person Days (PD) (95% CI 2.4-4.7). The distribution of positive swabs by month was: 21 in March 7 in April, 6 in May, 1 in June, 2 in July. Twenty-seven patients had symptoms while 10 patients, who have had contact with infected individuals, had positive swabs in absence of symptoms. Infected and hospitalised dialysis patients were 78%. Of the 29 hospitalized patients: 6 were in sub-intensive care, 16 in intensive care, of these 7 needed intubations, 9 underwent non-invasive ventilation. The adjusted cumulative mortality rate in dialysis patients was 6.8% (95% CI 6.0-7.6), the same measure for SARS-CoV-2 infected patients was 37.4% (95% CI 19.8-70.4) with an average follow-up of 205 PD. The adjusted mortality rate was 3.3 * 10,000PD (95% CI: 2.9-3.7) among dialysis patients and 21.2*10,000PD (95% CI: 11.1-40.7) among infected dialysis patients. Conclusion This study highlights a greater susceptibility of dialysis patients to SARS-CoV-2 infection, with a rate three times higher than that observed in the general population (source: Civil Protection Department). Mortality risk for dialysis patients with SARS-CoV-2 infection is about 6 times higher than in the dialysis patients it suggesting a major impact of infection on this fragile population.