Foot involvement in systemic sclerosis: a longitudinal study of 100 patients.
OBJECTIVE
To investigate the clinical and radiologic features of foot involvement in systemic sclerosis (SSc).


PATIENTS
One hundred patients (91 women, 9 men; mean age, 51.9 +/- 11 years) with SSc (mean disease duration, 17.4 +/- 10.5 years) were retrospectively studied. Seventy-four subjects had limited scleroderma and 26 diffuse scleroderma.


METHODS
Radiologic changes of foot involvement were assessed at presentation (time of diagnosis) and follow-up ranging from 1 to 28 years (median range, 7 years) and were compared with changes detected in the hands of each patient at the same presentation and follow-up. Correlations with skin and internal organ involvement were assessed.


RESULTS
Ninety patients had foot involvement clinically. Forty-three had it at initial evaluation; 47 developed it during follow-up. Median time to clinical event occurrence was 10 years (95% CI, 6.7-13.3) with 44% censored case probability at this time. The onset of clinically evident foot involvement was later in limited SSc than in diffuse SSc. In comparison with hands with SSc, feet with SSc had lower rates of necrotizing Raynaud's phenomenon and tendon friction rubs and decreased skin thickening scores, whereas arthralgias occurred significantly more often. At presentation, 37 patients had radiologic abnormalities of their feet compared with 69 of their hands (P <.001); the hands had a significantly higher prevalence of acroosteolysis (P <.001). At the end of the follow-up, 35 of 50 SSc patients had radiographic foot involvement compared with 50 of 51 with hand involvement (P <.001). A significantly higher prevalence of acroosteolysis (P <.001), calcinosis (P <.05), and erosions (P <.05) of the hands were detected at that time.


CONCLUSION
This study shows that compared with hand involvement in SSc, foot involvement in SSc has a later onset and is relatively less frequent but can be disabling.