An epidemiological analysis of osteoporotic characteristics in patients affected with rheumatoid arthritis in Kazakhstan

Purpose: We aimed to assess which of the major risk factors associated with rheumatoid arthritis (RA) severity are also associated with osteoporosis-related phenotypes (OP-RP) in the native population of Kazakhstan. Methods: Four hundred six RA patients (90.6% females) with 397 controls—unaffected first-degree relatives were recruited. Biochemical factors were recorded, and OP-RP were assessed using QCT scans and ultrasound densitometry (US) of the forearm to estimate cortical indices (CI), spongial bone mineral density (BMD_SPN), and US_T-scores. Results: In the RA affected female population, ~ 80% suffered from osteopenia or osteoporosis. All OP-RP were negatively correlated with age and female’s sex, as expected, and thus accordingly adjusted, resulting in consistent, significantly [p = 0.016 (CI), p < 0.0001 (both BMD_SPN and US_T-scores)] lower OP-RP estimates in affected females. Using multiple regression analysis for OP-RP manifestations, only age and disease duration appeared consistently associated with all three studied phenotypes, while menopause status or years following the onset of menopause were also significant for BMD_SPN and US_T-scores. However, when disease duration was examined, we found that it was significantly dependent on morning stiffness, ESR, total cholesterol levels, weight, and menopause status, which explains 38.6% of the disease duration. Conclusions: Approximately 80% of female RA patients suffer from osteoporosis or osteopenia in the study group, which appears from a young age. RA disease duration is the major risk factor for OP-RP deterioration, especially as assessed by BMD_SPNG, and US_T-scores. As a result, all OP-RP demonstrate significantly lower levels in comparison to sex- and age-matched unaffected individuals.