Aim: to study vitamin D levels in patients with COPD.

 Materials and methods. The study involved 50 people aged 41 to 85 years. Of the patients included in the study, 18% had stage II of the disease, 46% had stage III and 36% had stage IV COPD. According to the phenotypes of the disease, the patients were divided into 3 groups. Group 1 included 27 (54%) people with emphysematous COPD phenotype, group 2 - 7 (14%) patients with bronchitic phenotype, group 3 - 8 (16.1%) patients with mixed COPD phenotype. 8 patients had early stages of COPD, whose phenotypes had not yet formed.

Results. Evaluation of the level of vitamin D in the blood serum showed that the majority of patients with COPD had a deficiency or insufficient content of varying severity. In general, a pronounced deficiency was detected in 32% of the examined individuals, and insufficient vitamin D content was found in 66% of patients with various stages of COPD. Pronounced deficiency was found mainly in patients with severe and extremely severe COPD. There was no association of vitamin D deficiency with COPD phenotypes. Pronounced vitamin D deficiency was noted in the group of patients with emphysematous phenotype in 29.6% of cases, with bronchitic phenotype - 28.6% and mixed - 25%. Insufficient vitamin D content was observed in patients with moderate COPD in 62.9% of cases, severe - in 73.9% and extremely severe - in 55.5% of cases. Insufficient vitamin D content in COPD of emphysematous phenotype was noted in 62.9% and bronchitis ? in 71.4%.

Conclusion. Insufficient content and deficiency of vitamin Bit D is a biomarker that determines the nature of the course of COPD, which justifies the need for measures to correct these changes.