УДК 616.72-002:611-018.4]-07

Introduction. Patients with rheumatoid arthritis(RA)are twice as likely to have osteoporosis (OP) compared to the general population. The strength of bones depends on mineral substances, mainly represented by calciumphos phatemicrocrystals. The chiefrole in the regulation of calcium-phosphorus metabolism is played by vitamin D and parathormone(PTH). 
The aim of the study. To investigate markers of calcium-phosphorus metabolism in patients with rheumatoid arthritis accompanied by bone mineral density (BMD) disorders and to find out their diagnostic value.
Materials and methods. 76 patients with RA (64 premenopausal women and 12 mature men) were included in the study. All patients with RA were subjected toultrasound bone densitometry and according to its results, patients were divided into three groups: patients with RA and osteopenia, patients with RA and OP; RA patients without BMDdisorders. The control group included 22 healthy individuals of both genderswithout BMD abnormalities. To evaluate calcium-phosphorus metabolism, ionized calcium, total calcium, phosphorus, PTH, and vitamin Din blood serum, and levels of calcium and phosphorusin urine were detected.
Results. It was revealedthat concentration of total calcium in blood serum of patients with RA is lower compared tohealthy individuals, while the same index in urine ofpatients with RA accompanied byosteopenia,OP or without BMD disorders is higher compared to healthy people. The concentration of vitamin D is significantly lower in patients with RA and OP compared to patients with RA with osteopenia, without BMD disorders,or healthy individuals. The concentration of PTH is higher inhealthy individuals compared to patients with RA without BMD abnormalities or with osteopenia.
Conclusions. In patients with rheumatoid arthritis with osteopenia orosteoporosis, significantly more often than in patients with rheumatoid arthritis without a violation of bone mineral density, ionized and total calcium, phosphorus in serum and urine, as well asvitamin D indices have deviations from the reference valuesand are of diagnostic significance.