Prospective Study of Vitamin D Status at Initiation of Care in Critically Ill Surgical Patients and Risk of 90-Day Mortality*

Objectives:1) To characterize vitamin D status at initiation of critical care in surgical ICU patients and 2) to determine whether this vitamin D status is associated with the risk of prolonged hospital length of stay, 90-day readmission, and 90-day mortality. Design:Prospective cohort study. Setting:A teaching hospital in Boston, MA. Patients:Hundred surgical ICU patients. Interventions:None. Measurements and Main Results:Mean (± SD) serum total 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels were 17 ± 8 ng/mL and 32 ± 19 pg/mL, respectively. Mean calculated bioavailable 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were 2.5 ± 2.0 ng/mL and 6.6 ± 5.3 pg/mL, respectively. Receiver-operating characteristic curve analysis demonstrated that all of four vitamin D measures predicted the three clinical outcomes; total 25-hydroxyvitamin D was not inferior to the other measures. Median (interquartile range) hospital length of stay was 11 days (8–19 d). Poisson regression analysis, adjusted for biologically plausible covariates, demonstrated an association of total 25-hydroxyvitamin D with hospital length of stay (incident rate ratio per 1 ng/mL, 0.98; 95% CI, 0.97–0.98). The 90-day readmission and mortality rates were 24% and 22%, respectively. Even after adjustment for biologically plausible covariates, there remained significant associations of total 25-hydroxyvitamin D with readmission (odds ratio per 1 ng/mL, 0.84; 95% CI, 0.74–0.95) and mortality (odds ratio per 1 ng/mL, 0.84; 95% CI, 0.73–0.97). Conclusions:Serum 25-hydroxyvitamin D levels within 24 hours of ICU admission may identify patients at high risk for prolonged hospitalization, readmission, and mortality. Randomized trials are needed to assess whether vitamin D supplementation can improve these clinically relevant outcomes in surgical ICU patients.