Effect of Obesity and Vitamin D Levels on Outcome Prediction in Critical Patients

Background: Vitamin D is an important nutrient for maintaining cardiovascular, endocrine, immune, and nervous system health. Body mass index (BMI) is one of the factors influencing vitamin D levels. We aimed to study the factors that play a role in the outcomes and prognoses of critically ill patients. Method: This study was conducted at four teaching hospitals in Northern Taiwan between August 2018 and July 2020. A total of 1421 critically ill patients admitted to the intensive care units (ICUs) were eligible for assessment. Patients were classified into two groups based on serum 25(OH)D levels: sufficiency (³ 20 ng/ml) and insufficiency (< 20 ng/ml); and into four groups according to BMI: underweight (BMI < 18.5), normal weight (BMI 18.5–24.9), overweight (BMI 25–29.9), and obesity (BMI ³ 30). Statistical analyses were performed, and a p-value < 0.05 indicated a significant difference. Results: More than half (57.9%) of the critically ill ICU patients had vitamin D deficiency (VDD); and VDD lengthened ICU stay by 2.5 days in vitamin D-deficit patients as compared to that in vitamin D-sufficient patients. Patients with obesity had a 4.2-day longer ICU stay (16.7 days) than that of the BMI < 30 group (12.5 days), which was significant (p = 0.009). They also had the lowest vitamin D levels (17.3 ng/mL) and the highest 90-day mortality rate (17.3%) compared to the other BMI groups. Conclusion: In caring for critical patients, physicians need to pay more attention to vitamin D levels and BMI factors, which may impact their outcome prediction.