Risk Factors for Sarcopenia in Thai Patients with Rheumatoid Arthritis.

Background: Sarcopenia is a common condition that can occur in people with chronic inflammatory diseases, including rheumatoid arthritis (RA). The aim of this study was to determine the prevalence and factors associated with this condition in patients with RA.

Methods: This prospective cross-sectional study was conducted on 182 adult patients with RA. They were diagnosed with sarcopenia using the Asian Working Group's 2019 update on sarcopenia diagnosis. The body composition was estimated using a body impedance analyzer. Physical performance and muscle strength were evaluated with six-meter walk test and hand grip dynamometer, respectively. The Disease Activity Score (DAS) 28 and the Health Assessment Questionnaire (HAQ) were used to assess disease activity and functional status, respectively.

Results: The majority (87.4%) were female with a mean age (SD) of 59.2 (10.2) years. They had been suffering from RA for a long time (median disease duration [Interquartile range (IQR)] 11 [6-16] years) and had mildly active disease [mean DAS28 (SD) 2.61 (0.83)] with slightly functional disability [median HAQ (IQR) 0.34 (0-0.65)]. Of these, 26.4% had sarcopenia. Advanced age [relative risk (RR) 1.07 (95% confidence interval (CI) 1.02-1.11), p = 0.002], low body mass index (BMI) [RR (95% CI) 0.81 (0.72-0.90), p < 0.001], high disease activity [RR (95% CI) 1.64 (1.22-2.12), p = 0.045], and depression [RR (95% CI) 1.18 (1.01-1.37), p = 0.04] were independently associated with sarcopenia.

Conclusions: Sarcopenia was found to be common in Thai RA, and its independent risk factors are age, disease activity, BMI, and depression. Well-controlled disease activity may be beneficial for preventing or minimizing sarcopenia and improving patient outcomes.