Global ultrasound synovitis scores reflect symptom severity and patient outcomes in chronic chikungunya disease

Objectives Acute chikungunya virus infection often leads to chronic post-infection arthritis, but investigation and evaluation of treatment is hampered by the subjectivity of symptoms. This study was designed to evaluate ultrasound scores and serum inflammatory markers as objective measures for the severity of chronic post-chikungunya arthritis. Methods Patients with acute chikungunya virus infection were enrolled in a prospective study and followed up at 3, 6 and 12 months. Assessments included both a physical exam and standardized ultrasound examination of 40 joints. Symptom severity and patient reported outcomes were recorded, and serum inflammatory markers were measured. Global ultrasound synovitis and tenosynovitis scores were calculated and correlation of ultrasound and serum markers with clinical symptoms and outcomes was analysed. Results Sixty patients (mean age 34 years, 67% female) were followed up. Widespread joint involvement was observed in the acute infection phase. This was followed by increasing involvement of small joints contributing to persistent symptoms in 57% of patients at 3 months and 30% at 12 months. Global ultrasound scores for synovitis at 3 months correlated with tender joint counts (r = 0.54, P < 0.0001), pain severity (r = 0.59, P < 0.0001), musculoskeletal stiffness (r = 0.42, P < 0.001) and RAPID3 scores (r = 0.59, P < 0.0001), confirmed at 6 and 12 months. Serum inflammatory markers were poorly associated with persistent symptoms during follow-up. Conclusion Global ultrasound scores for synovitis were found to be a relevant measure to support clinical observations in studies of chronic post-chikungunya joint disease.