Discordance between Patient and Physician Assessments of Disease Severity in Systemic Sclerosis

OBJECTIVE: To describe the magnitude and correlates of discordance between patient and physician assessments of disease severity in patients with systemic sclerosis (SSc). METHODS: Subjects were patients enrolled in the Canadian Scleroderma Research Group Registry. The outcomes of interest were patient and physician global assessments of disease severity (scales ranging from 0-10). Predictors of disease severity represented the spectrum of disease in SSc (skin involvement, severity of Raynaud's phenomenon, shortness of breath, gastrointestinal symptoms and pain, number of fingertip ulcers, tender and swollen joints, creatinine, and fatigue). The results of the analysis were validated in an independent sample of patients with SSc from the United States. RESULTS: Patients perceived greater disease severity than physicians (mean difference 0.78 ± 2.65). The agreement between patient and physician assessments of disease severity was, at best, modest (intraclass correlation 0.3774; weighted κ 0.3771). Although both patients and physicians were influenced by skin scores, breathlessness, and pain, the relative importance of these predictors differed. Patients were also influenced by other subjective symptoms, while physicians were also influenced by disease duration and creatinine. The predictors explained 56% of the deviance in the patient global assessments and 29% in the physician assessments. These findings were confirmed in the US dataset. CONCLUSION: Patients and physicians rate SSc disease severity differently in magnitude and are influenced by different factors. Patient-assessed and physician-assessed measures of severity should be considered as complementary and used together in future studies of SSc.