Characterization of Bone Metabolism in Hungarian Psoriatic Arthritis Patients: A Case–Control Study.

Abstract

Background: Skeletal manifestations are predominant in psoriatic arthritis (PsA). The aim of this cross-sectional, case-controlled study is the complex assessment of areal and volumetric bone mineral density (BMD), fracture risk, vitamin D status and bone turnover markers, and its association with disease-related variables.Methods: Lumbar spine (L1-L4) and femur neck (FN) areal, and distal radius (DR) volumetric BMD, 10-year probability of major and hip osteoporotic fracture as assessed by the fracture risk assessment (FRAX) tool, markers of bone metabolism and disease activity were assessed.Results: Upon comparison of the disease and age- and sex-matched control groups, there was a statistically significant difference in FN areal (0.955±0.145 g/cm2 vs. 1.034±0.148 g/cm2; p=0.001) and DR total volumetric (285.7±61.8 mg/cm3 vs. 369.6±23.6 mg/cm3; p<0.001) BMD, 10 year probability for major osteoporotic (5.0% (0.7%-32%) vs. 3.5% (0%-17.5%); p=0.003) and hip (1.1% (0%-16%) vs. 0.5% (0%-6.1%); p=0.002) fracture and 25-hydroxyvitamin D status (53 (10-120) nmol/L vs. 67 (10-137; p<0.001) nmol/L). As compared to areal assessment, volumetric BMD measurements identified a significantly higher number of patients with low bone mass (T-Score £ -1.00) (34% vs. 88%, p<0.001). Upon multiple linear regression analysis, disease activity score, as determined by DAS28 assessment, was an independent predictor of 10-year probability for major osteoporotic fracture (B (95%CI) = 1.351 (0.379–2.323); p = 0.007).Conclusion: In the studied PsA cohort, disease activity was an independent predictor of 10-year probability for a major osteoporotic fracture, and complemented assessment of volumetric and areal BMD assured better efficacy at identifying those with low bone mass.