Relationship Between Vitamin D Level and Mortality in Adults With Psoriasis: A Retrospective Cohort Study of NHANES Data.

PURPOSE: Studies have shown an increased risk for mortality in patients with psoriasis. Furthermore, research has demonstrated an inverse relationship between 25-hydroxyvitamin D (25[OH]D) level and all-cause mortality. This study investigated the association between 25(OH)D level and all-cause mortality in US adults with psoriasis. METHODS: Data from NHANES (1999-2014 and mortality data through December 31, 2015) were analyzed. Quartiles of 25(OH)D level were created based on 25(OH)D levels among patients. Cox proportional hazards models were used for estimating hazard ratios (95% CI) for all-cause mortality. FINDINGS: A total of 82,091 participants were enrolled in the NHANES study from 1999 to 2014. Overall, 610 patients with psoriasis were identified in NHANES. The mean (SD) duration of follow-up was 5.61 (3.38) years (3427.92 person-years). The hazard ratio for mortality in the fully adjusted model was 0.12 (95% CI, 0.02-0.60; Ptrend = 0.01) in patients with a high 25(OH)D concentration compared to those with 25(OH)D deficiency. IMPLICATIONS: The 25(OH)D concentration was significantly inversely associated with all-cause mortality among these patients with psoriasis. Studies have shown an increased risk for mortality in patients with psoriasis compared to the general population. Vitamin D is not regularly metabolized in patients with psoriasis due to their skin abnormality. Vitamin D supplementation has been associated with a reduced mortality in patients with psoriasis. In practice, attention to vitamin D level is crucial, as is the use of vitamin D supplementation, for improving the health of these patients.