Clinical and laboratory markers of rheumatoid cachexia in rheumatoid arthritis

E.V. Papichev, B.V. Zavodovskii, L.E. Sivordova, Yu.R. Akhverdyan, Yu.V. Polyakova

Research Institute of Clinical and Experimental Rheumatology named after A.B. Zborovsky, Volgograd

Aim: to study the prevalence and clinical and laboratory characteristics of rheumatoid cachexia (RC) in patients with rheumatoid arthritis (RA), as well as to identify indicators, the determination of which can improve the RC detection.

Patients and Methods: 110 patients with RA were included in the retrospective study. All patients underwent a standard clinical and laboratory examination. Besides, laboratory methods were used to determine the highly sensitive C-reactive protein level, antibodies to cyclic citrullinated peptides (AB-CCP), bone metabolism indicators (CTX-I, P1NP, 25(OH)D), Urine CartiLaps / creatinine index. Using dual-energy x-ray absorptiometry (DEXA) with the Total Body program, the body composition was determined. RC was diagnosed when there was a decrease in the body mass index (BMI) of fat-free tissues below the 10th percentile and an increase in the BMI of adipose tissues above the 25th percentile.

Results: the study included subjects of working age (median 53.7 y.o.), mainly women with long-term disease duration (85.5% of patients had the advanced or late clinical stage of RA). The clinical profile of patients was dominated by rheumatoid factor (RF) positivity and AB-CCP, moderate disease activity, the presence of erosive arthritis, moderate limitation of physical activity. RC was diagnosed in 25 patients.

Statistically significant risk factors for the RC development is the RA duration and the presence of RF. The long disease duration increases the risk of developing this condition by 5.8%. Among RF-negative patients, RC was almost 10 times less common (OR 0.11, p=0.032). RA duration with the maximum total value of sensitivity and specificity for RC was 9.5 years (60% sensitivity and 38% specificity). In the group of patients with RC (n=20), the median cumulative dose of glucocorticoids (GC) was statistically higher than in the group without RC (n=68): 8,5 [6,2–17,5] g and 5.8 [3.6–13.7] g, respectively (Z=-1.98, p=0.047). Among the patients who continued receiving GC during the study, 16 were patients with RC with a median daily dose of GC of 5 [4–8] mg, and 61 — without RC, at a dose of GC of 8 [5–10] mg (Z=2.58, p=0.01).

Conclusion: it is advisable to determine the body composition in patients with an established diagnose of RA more than 10 years ago to detect RC. Alertness to this condition should be higher in the RF-positive form of arthritis and prolonged use of GC.

Keywords: rheumatoid arthritis, rheumatoid cachexia, rheumatoid factor, glucocorticoids.

For citation: Papichev E.V., Zavodovskii B.V., Sivordova L.E. et al. Clinical and laboratory markers of rheumatoid cachexia in rheumatoid arthritis. RMJ. 2021;7:3–6.