Hand impairment in systemic sclerosis : association of different hand indices with organ involvement

OBJECTIVE: To evaluate the association between the assessment tools used to quantify hand impairment and organ involvement in patients with systemic sclerosis (SSc). METHODS: Eighty consecutive SSc patients were assessed for hand impairment using the Hand Anatomic Index (HAI), finger-to-palm distance in flexion (FTP), and the Hand Mobility in Scleroderma (HAMIS) test. Cluster analysis was used to identify patients having similar characteristics on the basis of the pattern of organ involvement in order to create clinically homogeneous groups, and to correlate these clusters with the measures of hand involvement. Finally, we evaluated the discriminating ability of the indices to identify the patients whose clinical condition was more severe. RESULTS: Two major clusters were identified by cluster analysis on the basis of organ involvement. The first (cluster A) included 61 patients and the second (cluster B) 19 patients characterized by minor and major extent of organ involvement, respectively. The extent of organ involvement and the hand impairment were related. The scores of hand indices were lower in cluster B. The area under the receiver operating characteristic (ROC) curve (C-index) for the logistic model including all three indices was 0.85 (95% confidence interval 0.74–0.95). CONCLUSION: The seriousness of hand involvement as measured by the three indices was associated with the extent of organ involvement. Further studies of hand impairment scales are needed to provide validated guidance as meaningful clinical measures.