Abstract Background and Aims Early referral to nephrological care associates with improved long-term survival and lower hospitalization rates after dialysis initiation. Despite the strong evidence for this beneficial effect of early referral to pre-dialysis nephrological care in dialysis patients, the effect on COVID-19 incidence and outcome has not yet been investigated. Method Patients in the current study were recruited from a cohort of 349 consecutive patients who initiated dialysis between 2015 and 2018 at a dialysis network in Romania. All patients alive at the start of the pandemic (March 2020 = baseline) were included in this retrospective cohort study. Follow-up ended July 2021. At each visit, patients were screened for 2019 Coronavirus Disease (COVID-19) symptoms and symptomatic patients underwent PCR testing. We studied the effect of pre-dialysis nephrological care on COVID-19 incidence. Independent predictors of COVID-19 incidence were identified by multivariable logistic regression analysis. Results In total, 224 patients were included. Of these, 89 were early referral patients. At dialysis initiation, they had higher hemoglobin (median (25-75%), 10.0 (9.4-10.8) g/dL vs. 8.5 (7.6-9.4) g/dL, p<0.001), transferrin saturation (21.5 (16.8-25.3)% vs. 18.1 (13.4-23.5)%, p = 0.01), calcium (8.8 (8.3-9.1) mg/dL vs. 8.3 (7.8-8.8) mg/dL, p<0.001), phosphate (5.9 (5.0-6.8) mg/dL vs. 4.8 (3.9-5.8) mg/dL, p<0.001), and albumin (3.5 (3.2-4.2) g/dL vs. 3.5 (3.2-3.8) g/dL, p = 0.04), lower PTH (220 (136-357) pg/mL vs. 289 (148-510) pg/mL, p = 0.03), and initiated dialysis less often via a central dialysis catheter (40 (44.9%) vs. 132 (97.8%), p<0.001). Age, sex, diabetes, and Charlson Comorbidity Index did not differ between groups. During the 16 months of follow-up, 82 patients (36.6%) developed COVID-19. Incidence of COVID-19 was higher in patients with diabetes (32 (46.4%) vs. 50 (32.4%), p = 0.04), while early referral was weakly associated with a lower COVID-19 incidence (26 (29.2%) vs. 56 (41.5%), p = 0.06). Logistic regression, correcting for differences between early and late referral and differences between patients with and without COVID-19, identified a lower risk for COVID-19 among early referral patients (Table 1). No difference in mortality was detected between patients with and without COVID-19 during follow-up (19 (23.2%) vs. 36 (25.4%), p = 0.7). Conclusion Among prevalent dialysis patients, early referral to nephrological care before dialysis initiation was an independent predictor of lower COVID-19 incidence during a follow-up period of 16 month from the beginning of the pandemic.
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