Current instruments used to measure disease activity in patients with systemic lupus erythematosus (SLE) with musculoskeletal symptoms may be not be as effective compared with ultrasonography, according to study results published in Rheumatology.
Researchers conducted a cross-sectional observational study in 112 patients with SLE. Of the participants, 88 had current inflammatory musculoskeletal activity and 24 had prior activity with no present symptoms. Patients were assessed using the British Isles Lupus Assessment Group (BILAG) Index, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), physician global visual analog scale, and other joint disease determinants. Standard lab assessments and bilateral ultrasound, including grey scale and power Doppler, were also performed.
After analysis, investigators found that in study participants with current musculoskeletal activity, synovitis was positively identified using the BILAG index and SLEDAI in 38% and 32% of patients, respectively. In contrast, 68% of patients were positively identified with ultrasound. Moreover, 27% of participants with inflammatory musculoskeletal activity had abnormal ultrasound results, but no clinical evidence of synovitis.
The primary study limitation was the lack of a longitudinal follow-up period to determine the relative responsiveness of each diagnostic tool.
“In SLE patients with [musculoskeletal] symptoms, a large proportion of objective, clinically meaningful inflammation is only identifiable by [ultrasound]. The existing classification of [musculoskeletal] SLE using disease activity instruments based on joint swelling is inaccurate to guide patient selection for clinical trials, biologic therapy, or treat-to-target protocols,” the researchers concluded.
Zayat AS, Mahmoud K, Md Yusof MY, et al. Defining inflammatory musculoskeletal manifestations in systemic lupus erythematosus [published online September 27, 2018]. Rheumatology. doi:10.1093/rheumatology/key277