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

Critical Care Medicine
Q1
Jun 2014
Citations:109
Influential Citations:5
Observational Studies (Human)
83
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Methods
Design: Prospective cohort study conducted in two 18-bed surgical ICUs at Massachusetts General Hospital, Boston. Participants: 100 adult surgical ICU patients (mean age 65 ± 16 years; 58% female; 91% white) expected to require at least 48 hours of critical care; blood samples drawn within 24 hours of ICU admission. Eligibility included ability to consent (or surrogate) and exclusions: anemia (hematocrit <25%), pregnancy or immediate postpartum status, recent vitamin D supplementation ≥4000 IU/d, transfer from another ICU, prior ICU within 1 year, lack of suitable healthcare proxy, high likelihood of death within 24 hours, or refusal.
Results
Vitamin D status at ICU initiation predicted all three outcomes (hospital length of stay, 90-day readmission, and 90-day mortality). All four measures (total 25(OH)D, bioavailable 25(OH)D, total 1,25(OH)2D, and bioavailable 1,25(OH)2D) were predictive; total 25(OH)D was not inferior to the others. Within 24 hours of ICU admission, higher total 25(OH)D was associated with shorter hospital LOS (IRR per 1 ng/mL 0.98, 95% CI 0.97–0.98) and lower risk of 90-day readmission (OR per 1 ng/mL 0.84, 95% CI 0.74–0.95) and 90-day mortality (OR per 1 ng/mL 0.83, 95% CI 0.73–0.97). The 90-day readmission rate was 24% and the 90-day mortality rate was 22%. Stepwise analyses retained total 25(OH)D plus APACHE II (and albumin/calcium for LOS). Authors conclude that total 25(OH)D on ICU admission is inversely associated with mortality and related outcomes; causality cannot be inferred from this observational study, and prospective studies are needed to validate and explore whether optimizing vitamin D status could improve outcomes in surgical ICU patients.
Limitations
Small, single-center observational study (n=100); potential residual confounding; bioavailable D estimated from formula-based methods; limited power to assess ICU LOS; findings may not generalize to medical ICU or non-surgical populations; possible missing readmission data if admitted elsewhere; cannot establish causation.

Abstract

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 ...