Association of low serum 25-hydroxyvitamin D levels and mortality in the critically ill*

Abstract

OBJECTIVE: We hypothesized that deficiency in 25-hydroxyvitamin D before hospital admission would be associated with all-cause mortality in the critically ill. DESIGN: Multicenter observational study of patients treated in medical and surgical intensive care units. SETTING: A total of 209 medical and surgical intensive care beds in two teaching hospitals in Boston, MA. PATIENTS: A total of 2399 patients, age ≥ 18 yrs, in whom 25-hydroxyvitamin D was measured before hospitalization between 1998 and 2009. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Preadmission 25-hydroxyvitamin D was categorized as deficiency in 25-hydroxyvitamin D (≤ 15 ng/mL), insufficiency (16-29 ng/mL), and sufficiency (≥ 30 ng/mL). Logistic regression examined death by days 30, 90, and 365 post-intensive care unit admission, in-hospital mortality, and blood culture positivity. Adjusted odds ratios were estimated by multivariable logistic regression models. Preadmission 25-hydroxyvitamin D deficiency is predictive for short-term and long-term mortality. At 30 days following intensive care unit admission, patients with 25-hydroxyvitamin D deficiency have an odds ratio for mortality of 1.69 (95% confidence interval of 1.28-2.23, p < .0001) relative to patients with 25-hydroxyvitamin D sufficiency. 25-Hydroxyvitamin D deficiency remains a significant predictor of mortality at 30 days following intensive care unit admission following multivariable adjustment (adjusted odds ratio of 1.69, 95% confidence interval of 1.26-2.26, p < .0001). At 30 days following intensive care unit admission, patients with 25-hydroxyvitamin D insufficiency have an odds ratio of 1.32 (95% confidence interval of 1.02-1.72, p = .036) and an adjusted odds ratio of 1.36 (95% confidence interval of 1.03-1.79, p = .029) relative to patients with 25-hydroxyvitamin D sufficiency. Results were similar at 90 and 365 days following intensive care unit admission and for in-hospital mortality. In a subgroup analysis of patients who had blood cultures drawn (n = 1160), 25-hydroxyvitamin D deficiency was associated with increased risk of blood culture positivity. Patients with 25-hydroxyvitamin D insufficiency have an odds ratio for blood culture positivity of 1.64 (95% confidence interval of 1.05-2.55, p = .03) relative to patients with 25-hydroxyvitamin D sufficiency, which remains significant following multivariable adjustment (odds ratio of 1.58, 95% confidence interval of 1.01-2.49, p = .048). CONCLUSION: Deficiency of 25-hydroxyvitamin D before hospital admission is a significant predictor of short- and long-term all-cause patient mortality and blood culture positivity in a critically ill patient population.