Bone Health in Rheumatoid Arthritis: What Can Studies of Bone Microarchitecture Tell Us?

Abstract

Introduction: Rheumatoid arthritis (RA) is associated with changes in skeletal health, including increased risk of fracture. This study used a novel technique, high-resolution quantitative CT (HRpQCT), to assess bone microarchitecture in patients with RA. Methods: There were 59 patients (female: 41; male: 18) with RA recruited. They underwent dual energy X-ray absorptiometry and HRpQCT of the radius and tibia. The questionnaire information included age, sex, BMI, disease duration, comorbidities, medication use, smoking and alcohol consumption, rheumatoid factor (RF) or cyclic citrullinated peptide (CCP) status, and disease activity. HRpQCT results were compared with published estimated age and sex-specific values. Results: There were 55 patients (female: 39; male: 16) who had either radial or tibial scans available. The mean age was 55.8 (standard deviation [SD]: 12.6) years and median disease duration was 11.4 years (interquartile range [IQR]: 6.3–19.4). Mean BMI was 27.2 (SD: 5.8). Forty-nine (90.7%) participants were RF or CCP positive, with disease severity ranked as severe in 33 (61.1%) patients and moderate in 20 (37.0%). Fifteen participants (27.8%) had previously taken steroids and 47 (85.5%) were receiving tumour necrosis factor inhibitor (TNF-i) medication. Radial trabecular number and density were lower than expected, and trabecular separation was greater than expected (p<0.05), though tibial results were similar (p<0.10 for trabecular number and separation). No difference in cortical values reached statistical significance in this sample. Previous use of steroids was associated with greater radial periosteal circumference (p<0.05, adjusted for sex) and use of TNF-i agents was associated with lower radial total and trabecular area (p<0.05, adjusted for sex). Conclusion: Trabecular bone microarchitecture differences were observed among patients with RA. Further studies with larger numbers of participants are needed.