[Analysis of the relationship between vitamin D₃ level and disease severity in hereditary angioedema]

Introduction: In recent years, many papers analyzed the relationship between serum vitamin D₃ level and the frequency and activity of various diseases at least partially attributed to immune mechanisms. Aim: We looked for correlations among the number and location of edematous episodes occurring in patients with hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) and the quantity of the C1-inhibitor used for supplementation as well as the vitamin D₃ levels of patients. Method: We measured vitamin D₃ levels in 118 of the 175 C1-INH-HAE patients of the National Angioedema Reference Center during the winter-spring (n = 111) and the summer-autumn periods (n = 105) in 2013-2014. Complement levels and clinical data were extracted from the National Angioedema Registry and from patient diaries. Results: The proportion of vitamin D₃ deficient patients (serum level <20 ng/ml) was approximately 59.5% during winter-spring, 27.6% in summer-autumn, and 23.5% during both periods. There was a significant difference between vitamin D₃ serum levels measured in the winter-spring or in the summer-autumn months (p<0.0001). The same applies to the number of the vials of C1-inhibitor concentrate administered as acute treatment for angioedema attacks (p = 0.01). In any season, vitamin D₃ level did not correlate with the number of attacks experienced by the patients during the given period or of the vials of C1-inhibitor concentrate administered. Conclusions: We could not demonstrate a relationship between vitamin D₃ level and the frequency or location of edematous episodes in HAE patients. The need for treatment (as reflected by the number of the vials administered) was higher in the winter-spring period. As vitamin D₃ deficiency was more severe than expected in our patients, supplementation is clearly necessary. Orv Hetil. 2019; 160(25): 987-993.