A recent meta-analysis of over 4,000 participants found that vitamin D deficiency is associated with increased incidence of hospital mortality among critically ill adults.
Research has provided a large amount of evidence that indicates vitamin D deficiency is related to adverse health outcomes in critically ill patients, such as higher infection rates, prolonged length of stay, and hospital mortality.
However, a few studies from this past year have raised concerns regarding these findings. One cohort of 180 critically ill patients found no association between low vitamin D levels and increased mortality rates. This study suggested that those with vitamin D levels above 100 ng/ml experienced significantly higher mortality rates when compared to the other participants.
Given this conflicting evidence, researchers from China recently conducted a large meta-analysis to help clear up the conflicting research.
The researchers included seven cohort studies, three retrospective and four prospective cohorts, equaling a total of 4,204 participants into their meta-analysis. All cohorts focused on the relationship between vitamin D status and hospital or ICU mortality.
After analyzing the data, here is what they found:
- Vitamin D deficiency was significantly associated with increased hospital mortality (p < 0.001).
- Patients who were vitamin D deficient were 76% more likely to die in the hospital.
- All studies defined vitamin D deficiency differently, but stratifying participants based on specific vitamin D levels yielded similar results.
The researchers concluded,
“This study showed that vitamin D deficiency is associated with an increased hospital mortality in critically ill adult patients. However, there is not enough evidence to conclude that vitamin D deficiency is associated with increased ICU mortality in critically ill adult patients, which need more studies to probe further into it in the future.”
They went on to add,
“Vitamin D levels may not only predict disease severity and outcomes but also contribute to the co-morbidities commonly seen in critically illness.”
They pointed out that some studies were conducted in specific ICUs, such as a surgical ICU, which limits the study’s generalizability to all hospital patients. Also, the cohorts defined vitamin D deficiency differently which could affect the study’s primary findings.
It is unlikely that clinical trials comparing vitamin D to a placebo group of critically ill patients will ever be conducted due to ethical objections. Future studies should find the safest and most effective dose of vitamin D for critically ill patients.