The epidemiology of morphea (localized scleroderma) in Olmsted County 1960-1993

TL;DR: Morphea, and its subtypes, are more common than previously recognized, and can lead to important disability and the survival rate was not significantly different from the general population.

Abstract: Objective. To determine the incidence, prevalence, survival rates, clinical manifestations, and longterm outcome of patients with morphea (localized scleroderma) and its subtypes over a 33 year period in Olmsted County, Minnesota. Methods. We used the unique data resources of the Rochester Epidemiology Project to review all Olmsted County medical records with any potential diagnosis consistent with morphea (including plaque, generalized, bullous, linear, and deep entities) from 1960 through 1993. Results. We screened 1030 medical records and identified 82 (59 female ; 23 male) cases of morphea first diagnosed between 1960 and 1993. All cases were followed until death or migration from Olmsted County, a total of 754 person-years of observation. The annual age and sex adjusted incidence rate per 100,000 population was 2.7 (95% confidence interval 2.1, 3.3). The incidence rate increased significantly over the 33 years (p = 0.0037) on an average of 3.6% per year. The prevalence (estimated using cumulative incidence) at 80 years of age was about 2/1000. 50% of the patients had a cutaneous softening or evidence of disease resolution by 3.8 years' duration. The shortest active disease duration was found in the plaque group (50% resolution or skin softening by 2.7 years) compared to 5.5 years in the deep group. Arthralgias, synovitis, uveitis, and joint contractures were more frequent in the linear and deep categories. Although 9 patients (11%) developed some disease related disability over the followup period, this was common (44%) in the deep group. No case of morphea developed severe internal organ involvement and none progressed to systemic sclerosis. The survival rate was not significantly different from the general population (p = 0.409). Conclusion. Morphea, and its subtypes, are more common than previously recognized, and can lead to important disability.