title: Dual X-Ray Absorptiometry Whole Body Composition of Bone Tissue in Rheumatoid Arthritis - a Cross-Sectional Study.
abstract: OBJECTIVE
  Previous studies of bone tissue in rheumatoid arthritis (RA) using dual X-ray absorptiometry (DXA) concentrated on regions of interest that were used to diagnose osteoporosis. This study aimed to compare the whole body bone tissue (wbBT) of RA patients with healthy subjects and to identify the RA variables which significantly predict wbBT.
  
  
  METHODS
  The study was cross-sectionally designed to include postmenopausal RA patients and age-matched healthy female controls. All 107 RA patients and all 104 controls underwent clinical examination, laboratory tests and whole body DXA composition, which recorded total and regional bone indices. Non-parametric standard statistical test and regression models after data normalization were used to assess correlations, associations and differences.
  
  
  RESULTS
  Compared to controls, RA patients had significantly lower whole body and regional bone mass (14.9 kg compared to 15.5 kg; p = 0.031). Disease duration (r = -0.402 ; p < 0.001), C-reactive protein (r = -0.279; p = 0.015) and inflammation (2.5% wbBT compared to 2.9%; p = 0.043), radiographic damage (14.3 kg compared to 16.2 kg; p < 0.001), disease activity scores (r = -0.275 ; p = 0.018 for HAQ) are significantly correlated/associated with lower wbBT. Clinical structural damage is associated with lower wbBT and it can significantly predict them (R2 = 0.014; p = 0.001), while glucocorticoid treatment, even in low doses, was associated with lower wbBT percent (2.6% compared to 2.8%; p = 0.045). Treatment with biologics was associated with a lower rate of whole body osteoporosis (0% compared to 22.2%; p = 0.013).
  
  
  CONCLUSIONS
  The main associated factors with the generalized bone loss in female RA patients are disease duration and disease activity. Clinical structural damage is the most powerful predictor of the whole body bone loss. These results suggest a general disturbance of skeletal bone metabolism in RA and could explain a greater risk of fragility fractures of non-central sites (e.g. ribs, tibia, ankles etc.) compared to post-menopause osteoporosis.
authors.affiliation: "Sfânta Maria" Clinical Hospital, Bucharest, Romania ; Department of Internal Medicine and Rheumatology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
authors.forename: Claudiu
authors.initials: C
authors.lastname: Popescu
authors.affiliation: "Sfânta Maria" Clinical Hospital, Bucharest, Romania ; Department of Internal Medicine and Rheumatology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania ; Research Centre on the Pathology and Treatment of Systemic Rheumatic Diseases, Bucharest, Romania.
authors.forename: Violeta
authors.initials: V
authors.lastname: Bojinca
authors.affiliation: "Sfânta Maria" Clinical Hospital, Bucharest, Romania ; Department of Internal Medicine and Rheumatology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania ; Research Centre on the Pathology and Treatment of Systemic Rheumatic Diseases, Bucharest, Romania.
authors.forename: Daniela
authors.initials: D
authors.lastname: Opris
authors.affiliation: "Sfânta Maria" Clinical Hospital, Bucharest, Romania ; Department of Internal Medicine and Rheumatology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania ; Research Centre on the Pathology and Treatment of Systemic Rheumatic Diseases, Bucharest, Romania.
authors.forename: Ruxandra
authors.initials: R
authors.lastname: Ionescu
keywords: bone; rheumatoid arthritis; whole body DXA