Comparing bone mineral density in rheumatoid arthritis and psoriatic arthritis

Background: Changes in patients’ bone mineral density (BMD) is one of the problems in patients with rheumatoid arthritis, which can be due to the use of corticosteroid drugs to reduce patients' symptoms or due to the aging process in patients. In this study, we decided to compare BMD in patients with psoriatic arthritis and rheumatoid arthritis. Methods: This study as a cross-sectional descriptive-analytical study was performed to evaluate BMD in patients with psoriatic arthritis (n = 59) and rheumatoid arthritis (n = 41) that referred to Rasoul Akram Hospital in Tehran between 2016 and 2020. All patients were assessed by bone density scan (dual-energy X-ray absorptiometry or DEXA scan) to determine T score at the two spine and femur sites. Results: In the rheumatoid arthritis and psoriatic arthritis groups, the mean spine T score was -1.11±0.18 and -1.38±0.48, respectively, which did not show a significant difference between the two groups (p = 0.556). Similarly, in the two groups with rheumatoid arthritis and psoriatic arthritis, the mean femur T score was -1.36±0.17 and -1.78±0.61, respectively, which did not show a significant difference between the two groups (p = 0.451). Considering the underlying parameters including age, sex and duration of the disease, the lack of differences in the values of spine and femur T scores between the two groups was still evident.  Conclusion: The change in BMD was equal in both rheumatoid arthritis and psoriatic arthritis that is not affected by gender, age or duration of disease.