Handgrip strength relative to age- and sex-specific reference values in hospitalised patients with highly active rheumatoid arthritis: a single-centre cross-sectional study.

Handgrip strength (HGS) is a valuable indicator of muscle function that can be used to identify patients with rheumatoid arthritis (RA) at risk of sarcopenia and other functional impairments. The aim of this study was to describe grip strength (HGS) in patients with rheumatoid arthritis (RA), to assess the frequency of low HGS, to quantify grip strength relative to age- and sex-specific reference values, and to identify the clinical factors associated with HGS. In this single-centre cross-sectional study, 70 patients with RA had their HGS measured sequentially on both arms using an electronic hand dynamometer, with three measurements taken per arm; the higher of the HGSmeasurementse was taken as the maximum. Low HGS was defined as < 27 kg for men and < 16 kg for women. The maximum HGS was additionally expressed as an age- and sex-adjusted z-score relative to normative data; deviations from the norm were tested using the Wilcoxon signed-rank test (with an assumed median z = 0). Spearman's correlation and multivariate linear regression were used to determine the presence of an association with the maximum HGS value. The patients were predominantly women (n = 55; 78.6%), with a mean age of 53.6 ± 13.3 years, presenting with a long-standing course of RF-positive, erosive, highly active disease (median DAS28-ESR 5.6). The mean maximum HGS was 23.9 ± 8.8 kg. Low HGS was observed in 28.6% of patients (20% of women, 60% of men). Compared with age- and sex-matched norms, grip strength was significantly lower in men (median z = -1.71, p = 0.001) and in women (median z = -0.55, p < 0.001) . HGS scores were inversely correlated with age (ρ = -0.4, p = 0.001) and current smoking (ρ = -0.41, p = 0.001) and positively associated with body mass index (BMI) (ρ = 0.35, p = 0.003). Older age was the only variable independently associated with lower grip strength (B = -0.21 kg/year, p = 0.012). In this study, grip strength was low relative to established sarcopenia thresholds and age- and sex-specific reference values.