Associations between balance capacity declining and sarcopenia with spinal osteoporotic fracture in patients with rheumatoid arthritis

Abstract

Objective To investigate the prevalence of balance capacity declining and sarcopenia in patients with rheumatoid arthritis (RA), and to explore the effect of balance capacity declining and sarcopenia on spinal osteoporotic fracture (OPF) in RA. Methods A total of 963 hospitalized patients with RA and 158 age, gender-matched normal subjects from Jan. 2013 to Oct. 2015 were recruited from department of Rheumatology and Immunology, the first affiliated hospital of Anhui Medical University. Anteroposterior and lateral X-ray scanning of vertebral column (T5-L5) was conducted for every individual and semi-quantity method were used as the standard for determining vertebral OPF. Two hundred and sixty-seven RA patients and 156 control individuals were measured by bioelectrical impedance method for detecting skeletal muscle mass. Berg balance scale method was used to determine the balance capacity in RA patients. Statistical analyses were performed using statistical product and service solutions (SPSS) software (Version 17.0). Comparison of frequency among different groups was used by χ2 test. Ranksum test was used to compare the median of measurement data in different groups when the data were skewed in distribution. Linear correlation between two indicators was represented with correlation coefficient. Multivariate regression was analyzed by binary logistic Regression (Backward LR). Results ① The prevalence of vertebral OPF in RA was 15.1% (141/936), which was higher than that in the control group (6/158, 3.8%) (χ2=18.658, P 40(P<0.05). ④ Linear correlation analysis found that Berg balance scale score was positively correlated with skeletal muscle index (SMI) (r=0.299, P<0.01), skeletal muscle mass of general body (r=0.251, P<0.01), muscle mass of right upper limb (r=0.225, P<0.01), muscle mass of left upper limb(r=0.221, P<0.01). muscle mass of trunk (r=0.230, P<0.01), muscle mass of right lower limb (r=0.228, P<0.01), muscle mass of left lower limb (r=0.245, P<0.01) in RA. ⑤Logistic regression analysis (LR Backward) discovered that age (OR=1.075, P=0.002, 95%CI (1.028,1.124)] was the risk factor for spinal OPF in RA patients, while skeletal muscle mass index (SMI) [OR=0.649, P=0.020, 95%CI (0.451, 0.933)] and Berg balance scale score [OR=0.957, P=0.016, 95%CI (0.924, 0.992)] were protective factors for the occurrence of spinal OPF in RA. Conclusion Sarcopeniaand balance capacity declining are probably correlated with spinal OPF in RA. Key words: Arthritis, rheumatoid; Sarcopenia; Balance capacity; Osteoporotic fracture