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. 