Background/Purpose:  Studies on association between inflammatory activity and body composition changes in rheumatoid arthritis (RA) are controversial due to some limitations: use of low accuracy methods to evaluate body composition such as body mass index (BMI), or methods with high cost and operational complexity (CT and MRI); analysis not separated by sex; inclusion of women with different menopausal status and inclusion of non validated criteria to assess disease activity. Currently, the best method in clinical practice for body composition analysis is dual energy X-ray absorptiometry (DXA). However, no studies on RA activity and body composition by DXA included evaluation of visceral adipose tissue in patients with long standing RA. Thus, we sought to verify the association between body composition by DXA, including visceral fat, and inflammatory activity in women with long standing established RA.

Methods:  78 postmenopausal women with RA (ACR 2010) were assessed by questionnaire, laboratory tests and body composition by DXA (muscle mass, total body fat and visceral fat). Patients with conditions known to influence body composition were excluded. Disease activity was assessed by composite indices (DAS28, CDAI, SDAI) and C-reactive protein (CRP). The potential association between body composition and disease activity was analyzed by Pearson correlation, Fisher´s test, ANOVA and Tukey´s test (P <0.05).

Results:  The mean age and disease duration were 61.1 ± 7.7 and 18.1 ± 10.9 years, respectively. 70.5% of women had BMI ≥ 25kg/m². The mean values of DAS28 and CRP were 3.57 ± 1.36 and 9.1 ± 10.9 mg/L, respectively. There was a negative and statistically significant correlation between CRP and appendicular muscle mass index (r = -0.234, P = 0.039). After adjusting for disease duration, BMI, physical activity, current and cumulative dose of prednisone and comorbidities, we found that women with CRP>10 mg/L had lower appendicular muscle mass index than those with CRP 5-10mg/L and CRP<5mg/L (6.3 ± 0.8 kg/m², 7.2 ± 1.2 kg/m² and 6.8 ± 1.0 kg/m², respectively; P = 0.013). Regarding to body fat, women with moderate inflammatory activity (PCR 5-10mg/L) had more total fat than those with CRP>10mg/L and CRP<5mg/L (12.4 ± 3.5 kg/m², 9.9 ± 3.6 kg/m² and 10.5 ± 2.8 kg/m², respectively; P = 0.014). Similarly, women with PCR 5-10mg/L had more visceral fat than women with very high and lower PCR (812.5 ± 266.4cm³, 604.3 ± 236.3cm³ and 658.9 ± 255.6cm³; P = 0.009).

Conclusion:  PCR was the only activity parameter associated with body composition in women with long-standing RA. High inflammatory activity that persists after a long disease duration was associated with lower muscle mass and lower fat mass values (including visceral adipose tissue), suggestive of more exuberant rheumatoid cachexia. Moreover, moderate activity was associated with higher values of visceral fat, which is known to be associated with increased cardiovascular risk. These results point to the existence of different body composition profiles according to RA inflammatory status, suggesting the importance of individualized approaches to sarcopenia and adiposity according to each disease activity level in long-standing established RA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/changes-on-body-composition-in-women-with-long-standing-established-rheumatoid-arthritis-differences-by-level-of-disease-activity/