ABSTRACT
AIMS: Vitamin D plays a role in innate immune system activation, and deficiency increases susceptibility to respiratory infections and disease severity including COVID-19. We determined whether vitamin D levels and medications were associated with contracting COVID-19, and disease severity defined by hospitalisation and dialysis patient mortality. METHODS: We reviewed serum vitamin D levels, and prescription of cholecalciferol and alfacalcidol along with corresponding medical records of adult dialysis patients from a United Kingdom tertiary centre between March 2020 and May 2021. COVID-19 infection was determined by polymerase chain reaction (PCR) results. RESULTS: 362 (35%) of 1035 dialysis patients tested PCR positive for COVID-19. COVID-19 positive patients had lower native median vitamin D (65 (39-95) versus 74 (40.5-101) nmol/L (p = .009) despite greater prescription of cholecalciferol (median 20 000 (20000-20 000) versus 20 000 (0-20 000) IU/week), p < .001, but lower prescription of alfacalcidol 0 (0-3.0) versus 2.0 (0.-5.0) ug/week, p < .001. On multivariate logistic regression COVID-19 infection was associated with haemodialysis versus peritoneal dialysis (p < .001), cholecalciferol dose (p < .001) and negatively with alfacalcidol (p < .001). However, serum vitamin D levels and alfacalcidol dosages were not significantly different for those requiring hospitalisation compared to those managed at home, although those who died were prescribed lower alfacalcidol dosages. CONCLUSION: Dialysis patients who contracted COVID-19 had lower levels of native vitamin D prior to COVID-19 and were prescribed lower dosages of alfacalcidol. However, there was no association between vitamin D status and disease severity. This retrospective observational analysis supports a potential role for vitamin D and susceptibility to COVID-19 infection in dialysis patients.