Comprehensive assessment of alterations in hand deformities over 11 years in patients with rheumatoid arthritis using cluster analysis and analysis of covariance

Abstract Background Although drug therapy for rheumatoid arthritis (RA) has recently improved, treating patients with established disease, whose hands have three major deformities (thumb deformity, finger deformities, and ulnar drift), remains a challenge. The underlying complex pathophysiology makes understanding these difficult, comprehensive assessment methods require accumulated skill long learning curves. We aimed to establish simpler composite method understand the of alterations in hand RA. Methods cohort 2004 clinically evaluated 134 (67 patients). repeated evaluations 2009 (100 52 patients) 2015 (63 37 after case exclusion. Thumb (swan-neck boutonnière deformity), drift were semi-quantitated entered as parameters into two-step cross-sectional cluster analysis data 2004. each plotted at evaluation point. Two-way covariance was used examine whether differences existed between points clusters deformity parameters. Results Five most appropriately described deformity: (i) 1, minimal deformity; (ii) 2, type 1 thumb (iii) 3, severe (iv) 4, 2 or 3 drift; (v) 5, swan-neck deformity. Clusters had higher function than moderate function. 1–4 similar disease duration but showed different paths progression from onset. represented conservative 5 progressive Over time, evolved other types worsened significantly. Conclusions Our identified five patterns course hand. Knowledge characteristics may allow rheumatologists more easily implement practical interventions determine functional prognosis.