Interaction effect of systemic inflammation and modifiable rheumatoid cachexia risk factors on resting energy expenditure in patients with rheumatoid arthritis

Abstract Background In rheumatoid cachexia (RC), high resting energy expenditure (REE) is associated with loss of muscle mass driven by proinflammatory cytokines. The objectives this study were to investigate parameters RC and the interaction between systemic inflammation modifiable risk factors for on REE. Methods Thirty‐five arthritis (RA) 19 non‐RA controls comparable in age/sex/race/body index (BMI) underwent measures REE indirect calorimetry. Homeostasis model assessment insulin resistance (HOMA‐IR) serum interleukin‐6 (IL‐6) used as IR inflammation, respectively. Regression models tested association dependent variables, including pre‐specified tests involving HOMA‐IR IL‐6 dietary intake protein per weight (PPW) IL‐6. Results Rheumatoid subjects mostly women (94%) had a median age 54 years (50.5, 70) BMI 30.5 kg/m 2 (26.1, 36.9). Approximately two‐thirds RA participants seropositive, disease duration [interquartile range (IQR)] DAS‐28 C‐reactive [IQR] 7.83 [4.89, 18.14] 1.7 mg/day [1.21, 2.78], demonstrated significantly higher levels compared ( P = 0.006). Fat‐free (FFMI, 0.33), 0.68), 0.13), estimates PPW tertiles 0.83) not different non‐RA. univariate analyses, was positively <0.001), FFMI FMI 0.001), but 0.10). After adjustment FFMI, we did observe significant associations [ β 4.66, 95% confidence interval (CI) [−33.16, 42.48], 0.80], −9.45, CI [−25.61, 6.72], 0.24), or 6.00, [−5.47, 17.46], 0.29) multiple regression IL‐6, PPW, their term, observed crossover effect upper tertile negative correlation −19.97, [−35.41, −4.54], 0.01). lower positive 42.24, [4.25, 80.23], 0.03). This supports an interplay Animal intake, which has more anabolic vegetable protein, among <0.001). Conclusions While can lead catabolism, individuals. Higher could attenuate patients.