Sarcopenia May Be a Risk Factor for Osteoporosis in Chinese Patients with Rheumatoid Arthritis

Osteoporosis (OP) has been classically considered a co-morbidity of rheumatoid arthritis (RA). This investigation determined the clinical significance of sarcopenia in patients with RA combined with OP or whether sarcopenia influences RA when combined with OP.

Data pertaining to the duration of RA, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR) were collected from 549 RA cases and 158 healthy individuals. Disease activity score at 28 joints (DAS28), the body mass index (BMI), health assessment questionnaire (HAQ), bone mineral density (BMD), and Sharp score were compared between the 2 groups.

The prevalence of OP (33.3% vs 12.7%, χ ²= 69.992, P < 0.0001) and sarcopenia (61.7% vs 9.0%, χ ²= 135.336, P < 0.01) was greater in patients with RA than in healthy controls. RA patients with sarcopenia had a higher incidence of OP at all measured sites than RA patients without sarcopenia (all P < 0.0001), and the incidence of OP was significantly higher than in patients with mild-to-moderate or severe RA without sarcopenia (P < 0.0001). Differences in age, gender, course of disease, CRP level, ESR, DAS28, BMI, HAQ, BMD, and Sharp score were statistically different between the RA with or without sarcopenia groups (P < 0.01). The incidence of OP and sarcopenia was higher in RA patients treated than not treated with glucocorticoids [GCs] (36.4% vs 29.3%, P < 0.05 and 66.1% vs 56.0%, respectively; P < 0.05). Logistic regression showed that the risk factors for OP in RA individuals were female (OR, 14.671; 95% CI, 6.877-31.300; P < 0.0001), age (OR, 1.100; 95% CI, 1.076-1.124; P < 0.0001), and sarcopenia (OR, 3.561; 95% CI, 2.214-5.726; P < 0.0001).

OP and sarcopenia are common in RA patients. Sarcopenia may be a risk factor for OP occurrence in Chinese patients with RA.