Objective. The study aimed to investigate the relationship between ankle involvement and disease activity in rheumatoid arthritis (RA), from clinical and ultrasound perspectives.
Methods. RA patients were recruited in 2018 in the random order of presentation from the out-patient clinic. On the same day of inclusion, all patients underwent clinical examination, laboratory tests (inflammatory markers), ankle ultrasound and patient-reported outcomes.
Results. The study included 183 patients with established RA, mostly women (86.3%), with mean age of 57.3 years. Clinical examination revealed 101 (55.2%) patients with at least one tender ankle and 56 (30.6%) patients with at least one swollen ankle. Regression analysis revealed that both clinically tender and swollen ankles were 2.8 and respectively 3.4 times more likely to reveal ultrasound ankle joint synovial hypertrophy (SH). The presence of ankle SH was associated with higher disease activity: for example, compared to patients without ankle SH, patients with ultrasound-detected SH in any ankle joint had significantly higher median DAS28CRP (4.60 compared to 2.73, p<0.001). Power Doppler (PD) activity of ankle SH produced similar results: PD signal presence (p<0.001) and PD grade (p = 0.009) were associated with higher median DAS28CRP. Ankle joint involvement had an independent effect on DAS28CRP-defined disease activity: for example, the absence of ankle SH independently and significantly decreased DAS28CRP with 0.985 points (p<0.001).
Conclusion. Clinical ankle involvement and ultrasound-detected ankle SH have a directly proportional relationship with disease activity in RA.
