Vitamin D supplementation in the critically ill: A systematic review and meta-analysis

Vitamin D insufficiency is reported in up to 50% of the critically ill patients and is associated with increased mortality, length of stay (LOS) in intensive care unit (ICU) and hospital, and respiratory disorders with prolonged ventilation. Benefits of vitamin D supplementation remain unclear. The aim of this systematic review was to evaluate the clinical benefits of vitamin D administration in critically ill patients.

We searched Medline, Embase, CINAHL and Cochrane database for randomized controlled trials (RCT) conducted on heterogeneous ICU patients comparing vitamin D administration to placebo. Evaluated outcomes included mortality, infectious complications, hospital/ICU LOS and length of mechanical ventilation. Two independent reviewers assessed eligibility, risk of bias and abstracted data. Data was pooled using a random effect model to estimate the risk ratio (RR) or weighted mean difference. Pre-defined subgroup analysis included oral-enteral vs. parenteral administration, high vs. low dose, vitamin d deficient patient, high vs. low quality trials.

Six RCTs (695 patients) met study inclusion. No reduction in mortality was found (P = 0.14). No differences in ICU and hospital LOS, infection rate and ventilation days existed. In the subgroup analysis, the oral-enteral group, there was no improvement in mortality (P = 0.12) or hospital LOS (P = 0.16). Daily doses >300,000 IU did not improve mortality (P = 0.12) and ICU LOS (P = 0.12).

In critically ill patients, Vitamin D administration does not improve clinical outcomes. The statistical imprecision could be explained by the sparse number of trials.