Association between vitamin D deficiency and post-acute outcomes of SARS-CoV-2 infection

Objectives This study aimed to investigate the association between vitamin D deficiency (VDD) and post-acute outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Methods This retrospective study used the TriNetX research network to identify COVID-19 patients between January 1 and November 30, 2022. Patients were matched using propensity score matching (PSM) and divided into VDD (< 20 ng/mL) and control (≥ 20 ng/mL) groups. The primary outcome was a composite of post-COVID-19 condition (identified by ICD-10 code), all-cause emergency department (ED) visits, hospitalization, and death during the follow-up period (90–180 days) after the diagnosis of COVID-19. Results From an initial recruitment of 42,674 non-hospitalized patients with COVID-19 and known 25(OH)D status, a VDD group of 8300 was identified and propensity matched with 8300 controls. During the follow-up period, the VDD group had a higher risk of the primary outcome than did the control group [hazard ratio (HR) = 1.122; 95% confidence interval (CI) = 1.041–1.210]. The VDD group also had a higher risk of all-cause ED visits (HR = 1.114; 95% CI = 1.012–1.226), all-cause hospitalization (HR = 1.230; 95% CI = 1.105–1.369), and all-cause death (HR = 1.748; 95% CI = 1.047–2.290) but not post-COVID-19 condition (HR = 0.980; 95% CI = 0.630–1.523), individually. Conclusion Among the COVID-19 patients, VDD might be associated with a higher risk of all-cause ED visits, hospitalization, and death during the post-acute phase.