Vitamin D Status and Clinical Outcomes in Acute Respiratory Distress Syndrome: A Secondary Analysis From the Assessment of Low Tidal Volume and Elevated End-Expiratory Volume to Obviate Lung Injury (ALVEOLI) Trial.

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a highly morbid condition that has limited therapeutic options. Optimal vitamin D status has been linked to immunological effects that may benefit critically ill patients. Therefore, we investigated whether admission 25-hydroxyvitamin D levels (25OHD) are associated with clinical outcomes in ARDS patients.

METHODS

We performed a secondary analysis of data from a randomized, controlled trial comparing oxygenation strategies in 549 patients with ARDS (NCT00000579). Baseline 25OHD was measured in stored plasma samples. We investigated the relationship between vitamin D status and ventilator-free days (VFD) as well as 90-day survival, using linear regression and Cox proportional hazard models, respectively. Analyses were adjusted for age, race, and Acute Physiology and Chronic Health Evaluation III score.

RESULTS

Baseline 25OHD was measured in 476 patients. 90% of these individuals had 25OHD <20 ng/ml and 40% had 25OHD <10 ng/ml. Patients with 25OHD <20 ng/ml were likely to be ventilated for 3 days longer than patients with levels ≥20 ng/ml (ß 3.41; 95%CI 0.42-6.39: = 0.02). Patients with 25OHD <10 ng/ml were likely to be ventilated for 9 days longer (ß 9.27; 95%CI 7.24-11.02: < 0.001) and to have a 34% higher risk of 90-day mortality (HR 1.34; 95% CI 1.06-1.71: = 0.02) compared to patients with levels 10 ng/ml.

CONCLUSIONS

In patients with ARDS, vitamin D status is associated with duration of mechanical ventilation and 90-day mortality. Randomized, controlled trials are warranted to determine whether vitamin D supplementation improves clinical outcomes in ARDS patients.