Characterization of bone metabolism in hungarian psoriatic arthritis patients: a case-control study

Skeletal manifestations are predominant in psoriatic arthritis (PsA). The aim of this cross-sectional, case-control 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.

Lumbar spine (L1-L4) and femoral 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.

Upon comparison of the disease and age- and sex-matched control groups, there was a statistically significant difference in FN areal (0.952 (0.607-1.292) g/cm² vs. 1.016 (0.760-1.550) g/cm²; p = 0.001) and DR total volumetric (284.3 (138.9-470.3) mg/cm³ vs. 367.0 (287.0-412.0) mg/cm³; p < 0.001) BMD, 10 year probability for major osteoporotic (3.7% (0.7-32%) vs. 2.6% (0-17.5%); p = 0.003) and hip (0.4% (0-16%) vs. 0.05% (0-6.1%); p = 0.002) fracture and 25-hydroxyvitamin D status (47.5 (10-120) nmol/L vs. 64 (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 mineral density (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).

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 mineral density.