Influence of Vitamin D Deficiency on the Rheumatoid Arthritis Activity and the Ways of Its Corrections

Introduction. Vitamin D deficiency (VDD) is a global problem of humanity. In Ukraine it is registered in 81.8 % of the adult population. In its turn, rheumatoid arthritis (RA) is the most common disease among the rheumatic diseases of the population of the Lviv region. Aim. To increase the efficiency of the comprehensive treatment of RA based on the study of the effect of VDD on the disease course and the ways of its corrections. Materials and methods. The study consisted of two phases: epidemiological and clinical. Patients who participated in the study, depending on their needs, underwent a general clinical examination, joint syndrome assessment, anthropometric examination, questionnaires (visual analogue scale (VAS), assessment of the disease activity by the physician and patient, DAS28 , two-photon X-ray absorptiometry, ultrasound densitometry of the heel bone, determination of total 25 (OH) D contentinserum (electrochemiluminescent and immunochemical with chemiluminescent detection methods of research), determination of the levels of rheumatoid factor (RF) and C-reactive protein (CRP) (immunoturbidimetric method), anti-CCP (flowcytometry), complete blood count, biochemical blood test with determination of activity of ionized calcium in serum, questionnaire-weight method of reproduction of a daily diet, mathematical methods for statistical processing of the obtained results. Results. It was determined that RA as the most common rheumatic disorder in Lviv region (409.7 cases per 100.000 population), has one of the highest incidence of primary morbidity (initial incidence of 19.3 per 100.000 population) and highest rate of hospitalization. Patients with RA have VDD in 54.9 % cases, vitamin D insufficiency in 37.6 %. Comparing the obtained results with epidemiological study held among the healthy population of Lviv region it was shown that the number of patients with RA and optimal serum 25(OH)D level was significantly lower (7.5 vs. 16.3 %, respectively, p = 0.04). The frequency of VDD and vitamin D in sufficiency was the same. Risk factors for VDD development in patients with RA turned out to be age, female gender, and body mass index. It was determined the significant negative correlation between the serum 25(OH)D level and markers of RA activity (DAS28-ESR, ESR, CRP). All this associations remained statistically significant after adjustment for gender, age and body mass index. VDD can be regarded as a significant predictor of the highest activity of RA (AUROC = 0.67; 95% CI = 0.513-0.83, p = 0.05). Correction of vitamin D status by the developed individual targeted therapy of VDD in combination with basic treatment of RA reduces the markers of disease activity and significantly decreases the pain syndrome measured by visual analog scale (p < 0.05). Conclusions. Developed and implemented in health care system algorithm of correction and monitoring of vitamin D status is aimed to improve the treatment andthe life quality of the patients with RA.