NAPLES, FLA. – Vitamin D deficiency is common in critically ill trauma patients and portends worse outcomes, a retrospective study suggests.
Among 200 trauma patients with available vitamin D levels, 26% were vitamin D deficient on ICU admission.
Dr. Joseph Ibrahim
"These patients have a higher APACHE II score, have a longer ICU stay, and will likely be hospitalized greater than 2 weeks," Dr. Joseph Ibrahim reported at the annual scientific assembly of the Eastern Association for the Surgery of Trauma.
Long known to be essential for bone development and wound healing, recent studies have demonstrated that vitamin D deficiency is a significant predictor of 30- and 90-day all-cause mortality in critically ill patients, even after adjustment for such factors as age, Charlson/Deyo index, sepsis, and season (Crit. Care. Med. 2012;40:63-72). It also has been shown to significantly predict acute kidney injury in the critically ill (Crit. Care Med. 2012;40:3170-9).
For the current analysis, vitamin D levels were drawn upon ICU admission, at 72 hours, and every 7 days until hospital discharge in 200 of 234 consecutive adult trauma patients admitted to the ICU at the Level 1 Orlando Regional Medical Center during a 4-month period. Deficiency was defined as 25-hydroxyvitamin D 20 ng/mL or less. All patients received nutritional support using a standard protocol, but not vitamin D supplementation.
Median vitamin D ICU admission levels in the 51 vitamin D–deficient patients were significantly lower than for nondeficient patients (16 ng/mL vs. 28 ng/mL; P less than .001). Levels decreased a median of 4 ng/mL at 72 hours in both groups, but only the sufficient group returned to admission baseline levels at week 2, reported Dr. Ibrahim, a critical care surgeon with the medical center.
"This demonstrates that if we wish to obtain normal vitamin D levels in these patients, we will have to supplement them with much higher doses than what we are providing with standard enteral formulas," he said in an interview.
Patients with vitamin D deficiency spent more time than did nondeficient patients in the ICU (median 3 days vs. 2.7 days) and hospital (median 8.4 days vs. 7.1 days), but these trends did not reach statistical significance.
Significantly more deficient patients, however, remained in the hospital for at least 2 weeks (37% vs. 20%; P = .01).
The investigators were unable to show a difference in mortality between the deficient and nondeficient groups (16% vs. 12%; P = .51), possibly because the study was underpowered, he said.
Deficient and sufficient patients did not differ in age (median 48 years vs. 44 years), body mass index (26.2 kg/m2 vs. 25.7 kg/m2), admission ionized calcium (1.06 mmol/L for both), or Injury Severity Score (14 vs. 13). Only APACHE II scores were significantly higher in deficient patients (20 vs. 15).
"It makes sense that with the significant difference in APACHE II score, one would expect to see a similar difference in mortality, but again we were unable to show this with this study," Dr. Ibrahim said.
Prehospital factors significantly associated with low vitamin D status were African American race, diabetes, and lack of vitamin D supplementation.
Vitamin D supplementation may be helpful in critically ill trauma patients during hospitalization, but more research is needed, Dr. Ibrahim said. The group is planning a supplementation study, looking at vitamin D dosing and frequency of testing.
"Our first goal was to demonstrate a significant incidence, which we did," he said. "It should be noted that the incidence was in a location with probably one of the highest amounts of sunshine in the country and that the findings may underestimate what one would find in other areas of the United States."
Dr. Oscar Guillamondegui, of Vanderbilt University Medical Center in Nashville, Tenn., who proctored the poster session, said he would expect vitamin D levels to be lower in acutely sick patients requiring ICU management because production of vitamin D–binding protein, a subprotein in the albumin family of proteins involved in vitamin D transport and storage, is decreased in high stress situations to allow for the increase in acute phase protein production.
"Although the data are intriguing, as a retrospective study, it is too early to suggest that supplementation is essential," he said. "I do believe this is great work and will stimulate several studies to prove the need for supplementation and for that, I commend Dr. Ibrahim and his group in their efforts."
Dr. Ibrahim and Dr. Guillamondegui reported having no financial disclosures.