The association between difficult-to-treat rheumatoid arthritis and probable sarcopenia.

Objectives: To identify factors associated with probable sarcopenia in patients with rheumatoid arthritis (RA).

Methods: Probable sarcopenia was diagnosed using the SARC-F questionnaire. Patients with difficult-to-treat RA (D2T-RA) were defined as those with a history of using ≥2 biological/targeted synthetic (b/ts) disease-modifying antirheumatic drugs (b/tsDMARDs) who had moderate or high disease activity. Among 486 patients, 101 were classified into the probable sarcopenia group (SARC-F ≥4), and 385 were classified into the non-probable sarcopenia group (SARC-F <4). Factors associated with probable sarcopenia were examined using multiple logistic regression analysis. Additionally, patients were divided into the D2T-RA (n = 38) and non-D2T-RA (n = 448) groups, and the proportion of probable sarcopenia and RA treatment status were compared.

Results: Factors associated with probable sarcopenia included age [adjusted odds ratio (OR): 1.03], body mass index (OR: 1.16), D2T-RA (OR: 3.39), and Health Assessment Questionnaire-Disability Index (OR: 1.38), and diabetes mellitus (OR: 2.77). The proportion of probable sarcopenia was significantly higher (60.5% vs. 17.4%), and the rate of methotrexate use was significantly lower (34.2% vs. 64.1%), in the D2T-RA group than in the non-D2T-RA group. Moreover, in the D2T-RA group, most patients used two or three b/tsDMARDs (two: 68.4%, three: 21.1%).

Conclusions: D2T-RA was associated with probable sarcopenia. Tight control by treatment enhancement may help overcome sarcopenia.