A preliminary disease severity score for juvenile systemic sclerosis

Objective To develop a preliminary disease severity score for juvenile systemic sclerosis (SSc). Methods We conducted an evidence- and consensus-based study that included the following 5 phases: 1) prospective collection of data regarding the demographic and clinical characteristics of patients with diffuse juvenile SSc who were followed up for at least 4 years or until death; 2) blinded evaluation of the disease course profiles of these patients by experts in juvenile SSc, so that patient profiles with a defined clinical course could be used as the gold standard for the score validation phase; 3) definition of candidate severity indices to be included in potential scores; 4) selection of the pediatric severity score with the best statistical performance, as determined by its ability to classify individual patients as having improvement or worsening of disease compared with baseline values or the previous evaluation; 5) validation of the efficiency of the selected score in patients with a mild, moderate, or severe disease course and comparison with the Medsger severity score for adults with SSc. Results Thirty-five patients classified as having a mild (n = 17), moderate (n = 10), or severe (n = 8) disease course entered the study. The selected pediatric SSc score, defined as the Juvenile Systemic Sclerosis Severity Score (J4S), included indices of 9 organ systems each scored on a scale of 0-4. To weight the importance of the involvement of different organ systems, a coefficient of severity was introduced. Compared with the modified Medsger severity score, the J4S performed significantly better in detecting change in severity, both in patients with a moderate disease course (0.89 versus 0.52) and in patients with a severe disease course (0.82 versus 0.75). Conclusion The J4S is a valid instrument to assess disease severity in juvenile SSc.