Classification at time of diagnosis and subsequent survival in children with cystic fibrosis.

The survival rates in 204 patients suffering from cystic fibrosis observed between January 1956 and June 1976 were recorded. The patients were divided into five groups according to the symptoms present at the time of diagnosis and survival rates were recorded separately for each group. Survival was less good in the group of patients presenting initially with pulmonary symptoms compared to the group presenting with gastrointestinal symptoms. In the group presenting with meconium ileus survival was poor initially, but later in the course of the disease it became similar to that observed in the other groups. The differences in survival between the different categories occurred during the first two years after diagnosis. The study shows that, on clinical grounds, a severe form of the disease which is characterized by early manifestation of pulmonary symptoms and poor survival can be distinguished from a more protracted form with a better survival. Because of the great inter-individual variability large numbers of patients will have to be evaluated in order to achieve statistically significant results in studies which attempt to compare different therapeutic approaches. If such numbers cannot be reached, it may be necessary to compare only patients who belong to the same symptomatic category.