Low serum 25-hydroxyvitamin D at critical care initiation is associated with increased mortality

Abstract

Objective: We hypothesized that deficiency in 25-hydroxyvitamin D at critical care initiation would be associated with all-cause mortalities.

Design: Two-center observational study.

Setting: Two teaching hospitals in Boston, MA.

Patients: The study included 1,325 patients, age ≥ 18 yrs, in whom 25-hydroxyvitamin D was measured 7 days before or after critical care initiation between 1998 and 2009.

Measurements: 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 postcritical care initiation and in-hospital mortality. Adjusted odds ratios were estimated by multivariable logistic regression models.

Interventions: None.

Key results: 25-hydroxyvitamin D deficiency is predictive for short-term and long-term mortality. Thirty days following critical care initiation, patients with 25-hydroxyvitamin D deficiency have an odds ratio for mortality of 1.85 (95% confidence interval 1.15-2.98; p = .01) relative to patients with 25-hydroxyvitamin D sufficiency. 25-hydroxyvitamin D deficiency remains a significant predictor of mortality at 30 days following critical care initiation following multivariable adjustment for age, gender, race, Deyo-Charlson index, sepsis, season, and surgical vs. medical patient type (adjusted odds ratio 1.94; 95% confidence interval 1.18-3.20; p = .01). Results were similarly significant at 90 and 365 days following critical care initiation and for in-hospital mortality. The association between vitamin D and mortality was not modified by sepsis, race, or neighborhood poverty rate, a proxy for socioeconomic status.

Conclusion: Deficiency of 25-hydroxyvitamin D at the time of critical care initiation is a significant predictor of all-cause patient mortality in a critically ill patient population.

Figure 1. Time-to-Event curves for the Primary End Point

Note: Unadjusted event rates were calculated with the use of the Kaplan-Meier methods and compared with the use of the log-rank test. Observations are censored at 1-year. Categorization of 25(OH)D is per the primary analyses. The global comparison log rank p value is 0.04.