Objective: We examined a clinical database for patients receiving financial aid for treatment to elucidate age at onset of intractable disease.
Methods: Data were obtained from the clinical database of patients receiving financial aid for treatment in 2003. Age at onset of disease was calculated by subtracting the year of birth from the year of onset as registered in the database. Percentiles for age at onset and peak onset age were evaluated for each intractable disease. Peak onset ages for primary immune-deficiency syndrome, subacute sclerosing panencephalitis, lysosomal diseases, epidermolysis bullosa and neurofibromatosis I and II were under 20 years.
Results: Peak onset ages for aortitis syndrome, systemic lupus erythematosus, Behcet's disease, adrenoleukodystrophy, multiple sclerosis, ulcerative colitis and Crohn's disease were between 20 and 50. Distributions of age at onset for aplastic anemia, idiopathic thrombocytopenic purpura, myasthenia gravis, moyamoya disease and sarcoidosis were bimodal. Peak onset age for many other diseases were > or = 40 years.
Conclusions: Using a clinical database for patients receiving financial aid for treatment, the distribution of ages at onset and peak onset ages could be systematically clarified for individual intractable diseases. Our study provides new information on the natural history of disease development.