Background In approximately 25% (1) of all cases of mixed connective tissue disease (MCTD) the disease presents during childhood and adolescence. Only few, small studies have examined disease outcome in patients with juvenile MCTD.

Objectives The aim of this study is to describe long-term outcome and clinical characteristics in a nationwide representative Norwegian juvenile MCTD population.

Methods Inclusion criteria in this cross-sectional study were fulfillment of the Kasukawa or Alarcon-Segovia criteria and symptom-onset before 18 years. All patients underwent a thorough clinical examination and charts were reviewed. As there are no criteria for remission in MCTD, this was defined as fulfillment of the Wallace criteria for remission in juvenile idiopathic arthritis, plus the absence of myositis, progressive lung- or esophageal manifestations- or progressive sclerodactyly (with or without Raynaud phenomena).

Results 54 patients with juvenile MCTD were identified. 2 patients had deceased, and 48 patients (92%) accepted to participate (88% females). Mean age was 14,0±4,8 years at diagnosis and 28.5±10.0 years at inclusion. Mean disease duration was 16.8±9.7 years. 2 of the patients had developed SLE, none had developed other connective tissue diseases. Of the 46 patients with continuous MCTD, only one patient developed pulmonal arterial hypertension.

At 16.8 year follow-up remission off medication was found in 8 patients (17%), remission on medication in 9 patients (20%), whereas 29 patients (63%) had active disease. 35 (70%) were currently on immunosuppressive treatment. Mean Physician's Global Disease Activity score was 18.7±15.7 (100 mm Visual Analogue Scale).

Conclusions In this Norwegian childhood-onset MCTD study we found that a majority of 63% still had active disease after mean 16.8 years disease duration. Only 17% were in remission off medication, and very few patients had evolved into another connective tissue disease. SLE-like disease was the most common disease pattern.

References

1. Burdt MA et al; Long-term outcome in mixed connective tissue disease: longitudinal, clinical and serologic findings. Arthritis Rheum, 1999. 42(5)

Disclosure of Interest None declared