Influence of vitamin D status on hospital length of stay and prognosis in hospitalized patients with moderate to severe COVID-19: a multicenter prospective cohort study.

Background: Vitamin D acts as a mediator in the immune system regulating antiviral mechanisms and inflammatory processes. Vitamin D insufficiency has been suggested as a potential risk factor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, although its impact on the prognosis of hospitalized patients with coronavirus disease 2019 (COVID-19) remains unclear.

Objective: This multicenter prospective cohort study was designed to investigate whether serum 25-hydroxyvitamin D [25(OH)D] concentration is associated with hospital length of stay and prognosis in hospitalized patients with COVID-19.

Methods: Patients with moderate to severe COVID-19 (n = 220) were recruited from 2 hospitals in Sao Paulo, Brazil. Serum 25(OH)D concentrations were categorized as follows: <10 ng/mL, 10 to <20 ng/mL, 20 to <30 ng/mL, and ≥30 ng/mL, and <10 ng/mL and ≥10 ng/mL. The primary outcome was hospital length of stay and the secondary outcomes were the rate of patients who required invasive mechanical ventilation and mortality.

Results: There were no significant differences in hospital length of stay when the 4 25(OH)D categories were compared (P = 0.120). Patients exhibiting 25(OH)D <10 ng/mL showed a trend (P = 0.057) for longer hospital length of stay compared with those with 25(OH)D ≥10 ng/mL [9.0 d (95% CI: 6.4, 11.6 d) vs. 7.0 d (95% CI: 6.6, 7.4 d)]. The multivariable Cox proportional hazard models showed no significant associations between 25(OH)D and primary or secondary outcomes.

Conclusions: Among hospitalized patients with moderate to severe COVID-19, those with severe 25(OH)D deficiency (<10 ng/mL) exhibited a trend for longer hospital length of stay compared with patients with higher 25(OH)D concentrations. This association was not significant in the multivariable Cox regression model. Prospective studies should test whether correcting severe 25(OH)D deficiency could improve the prognosis of patients with COVID-19.