Rheumatoid Arthritis Effect´s On Bone Mass and Muscle

BRANCE ML; PONS-ESTEL BA; QUAGLIATTO J; JORFEN M; BERBOTTO G; CORTESE N; RAGGIO JC; SOLDANO J; PALATNIK M; CHAVERO I; DIEGUEZ C; DI GREGORIO S; BRUN LR

Chicago

Congreso; 2018 ACR/ARHP Annual Meeting; 2018

American College of Rheumatology

Background/Purpose: Rheumatoid  arthritis (RA)  is  a progressive auto-immune  disease  characterized by chronic  inflammation whichleads to joint deformity and disability. However, the bone and muscle are alsoaffected. The aim of this study was to evaluate the total bone mineral density(tBMD) and total lean mass in rheumatoid arthritis patients. Methods: A total of 50 adult´s women with RA and a controlgroup (CG, n=34) matched by sex, age and body mass index (BMI) were included.All patients had more than 18 years and were from Rosario city (32º52´18´´S),Argentina. Exclusion criteria: pregnancy, intestinal malabsorption, chronicliver or kidney disease, cancer and drug which could affected the bone massexcept glucocorticoids. The whole body composition was performed by Dual X-RayAbsorptiometry (DXA) (Hologic discovery Wi). The muscle strength was evaluatedby handgrip strength (Baseline Hydraulic Hand Dynamometer, USA) and the physicalperformance by sit to stand test and timed up and go test. Date are expressedas mean±SD. Differences between groups were analyzed using the Student t test or Mann-Whitneytest as appropriate.Correlations were performed with Pearson or Spearman?s correlation test.Contingency tables were evaluated with c2 test. The difference was considered significant ifp<0.05. Results: No differences in age (CG: 55.1±12.7 y, RA:53.5±11.7 y), BMI (CG: 26.0±5.1, RA: 27.8±4.6) and percentage of pre andpostmenopausal women were included. According to BMI no differences in totalmass by DXA were observed (CG: 66.9±13.1 kg, RA: 68.0±13.1 kg). The total bonemineral content (tBMC) and tBMD were found decreased in RA patients (tBMC= CG:2111±319 g, RA: 1874±343 g, p=0.0036; tBMD= CG: 1.072±0.094 g/cm2,RA: 1.016±0.109 g/cm2, p=0.0255). Furthermore, a tendency to lowlean mass in RA patients were observed (CG: 57.3±5.2, RA: 55.7±5.3, p=0.06). Themuscular involvement was confirmed in muscle strength and physical performancetests. The RA group had significantly lower handgrip strength (CG: 21.4±4.9 kg,RA: 12.3±6.7, p<0.0001), lower performance in the sit to stand test (CG:14.7±4.5 s, RA: 17.9±5.7 s, p=0.0126) and timed up and go test (CG: 8.8±1.9 s,RA: 11.6±3.7, p=0.0003). A significant correlation between tBMD and total leanmass were found (r: 0.3, p=0.0128). In addition, significant correlationbetween regional BMD (left arm, right arm, left leg and right leg) and the leanmass of each region were observed. Therefore the loss of lean mass couldexplain the loss of bone mass. On the other hand, higher percentage of fat wasfound in RA patients (CG: 39.4±5.7, RA: 41.9±5.7, p=0.06). Conclusion: the disease activity could affect not only thejoint and bone mass, but also the muscle which contributes to bone loss andlead to osteopenia and osteoporosis in RA patients.