Skin thickness score as a predictor and correlate of outcome in systemic sclerosis: High-dose versus low-dose penicillamine trial

Objective. To study the clinical implications of a skin thickness score ≥26 at first visit and of softening of sclerodermatous skin in a cohort of systemic sclerosis (SSc) patients with diffuse cutaneous scleroderma. Methods. Skin and visceral involvement were assessed in 134 SSc patients with diffuse scleroderma (mean ± SD duration of SSc 16 ± 4 months) as they entered a multicenter drug trial and again at 2 years of followup. Advent of mortality and scleroderma renal crisis (SRC) were assessed during a followup of 4.0 ± 1.1 years (mean ± SD). Logistic and linear regression were used to examine the relationship of baseline skin score to morbidity, mortality, and visceral involvement and the relationship of changes in skin score to changes in physical examination, laboratory, and functional variables over 2 years. Results. A baseline skin score ≥20 was associated with heart involvement at baseline (odds ratio [OR] 3.10, 95% confidence interval [95% CI] 1.25-7.70) and was predictive of mortality (OR 3.59, 95% CI 1.23-10.55) and SRC (OR 10.00, 95% CI 2.21-4.5.91) over 4 years. Multivariate linear regression demonstrated that a model with skin score at baseline (P = 0.0078) and changes in large joint contractures (P = 0.0072), tender joint counts (P = 0.0119), handspread (P = 0.0242), and Health Assessment Questionnaire disability index (HAQ-DI) (P = 0.0244) explained the change in skin score over 2 years (R ² = 0.567). Multivariate logistic regression demonstrated that the investigator's global assessment of improvement was best explained by a model with skin score and HAQ-DI (R ² = 0.455). Conclusion. A baseline skin score ≥20 was associated with heart involvement at baseline and predicted mortality and SRC over the subsequent 4 years. Improvement in skin score in these patients with diffuse cutaneous scleroderma was associated with improvement in hand function, inflammatory indices, joint contractures, arthritis signs, overall functional ability, and the examining investigator's global assessment of improvement.