Risk Factors Of Sarcopenia In Rheumatoid Arthritis

ObjectiveTo investigate the risk factors of sarcopenia in patients with rheumatoid arthritis(RA).MethodsClinical data of 123 RA patients admitted to our hospital from June 2019 to December 2020 were collected(basic data,laboratory examination,bone mineral density and body composition,dominant hand grip strength,application of glucocorticoid and bio-Dmards,etc.).BMD,body composition and dominant hand grip strength of 123 healthy subjects during the same period were mersured and collected,either.Serum of the subjects was collected for myostatin(MSTN)detection.The differences in body composition,BMD,muscle strength,the incidence of sarcopenia and osteopenia/osteoporosis were compared between RA patients and healthy controls,and among patients with different disease activity.The Differences in disease characteristics were compared between patients with and without decreased skeletalmuscle mass.The expression level of serum MSTN was compared between RA patients and healthy people,RA patients with and without decreased muscle mass.Correlation and regression analysis were performed on the appendicular skeletalmuscle mass index(ASMI)and the occurrence of sarcopenia in RA patients,to investigate the risk factors of skeletalmuscle mass decreasing and sarcopenia..ResultsCompared with healthy controls,total skeletalmuscle mass,appendicular skeletalmuscle mass,ASMI,muscle strength,BMD-Lumbar,BMD-Hip,Z-Lumbar and Z-Hip were significantly decreased(P=0.000～0.039).Serum MSTN levels,the incidence of skeletalmuscle mass decreasing and sarcopenia were significantly increased in RA patients(P=0.000～0.001).Compared with RA patients with normal skeletalmuscle mass,the disease duration,ESR,CRP,IL-6,DAS28,CDAI,SDAI,HAQ score and the incidence of osteopenia/osteoporosis were significantly increased in patients with decrease skeletalmuscle mass(P=0.000～0.019).The incidence of muscle strength decreasing and sarcopenia in the medium-high activity group and low activity group were significantly higher than those in the remission group(P < 0.05),and the incidence of skeletalmuscle mass decreasing in the medium-high activity group was significantly higher than that in the remission group(P < 0.05).In RA patients,ASMI was negatively correlated with CRP,ESR,IL-6 and HAQ scores,and positively correlated with 25-(OH)D(P < 0.05).Disease duration,sex,25-(OH)D,glucocoticiod use and osteopenia/osteoporosis significantly effected ASMI(P=0.000～0.048).IL-6 was an independent risk factor for sarcopenia in RA patients(P=0.029).ConclusionRA Patients are more likely to have a loss of skeletalmuscle mass and strength than healthy people.Active RA patients are more likely to experience a decreasing in skeletalmuscle mass and strength than those in remission.The expression level of MTSN in RA patients is higher than that in healthy people.In RA patients,ASMI is negatively correlate with CRP,ESR,IL-6 and HAQ scores,and positively correlate with 25-(OH)D;ASMI was significantly decresed in patients with long disease duration,women,low 25-(OH)D,glucocoticiod use,and osteopenia/osteoporosis;IL-6 is an independent risk factor for sarcopenia.Attention should be paid to the prevention and treatment of sarcopenia in RA.