Background: A study was undertaken to evaluate whether an early diagnosis by neonatal screening may improve the long term prognosis of patients with cystic fibrosis and to assess the influence of expert management started immediately after the diagnosis.
Methods: Comparative clinical follow up in three birth cohorts of patients with cystic fibrosis was performed at the Cystic Fibrosis centre in Groningen in close collaboration with paediatricians in general hospitals in the north-eastern part of the Netherlands. The first birth cohort (n = 19) was detected by screening and the two other cohorts were detected clinically, one (n = 30) consisting of patients born during the screening programme and the other (n = 32) of patients born during the six years immediately after the screening programme ended. The total number of patients in the three birth cohorts included all patients with cystic fibrosis born in this area during a 12 year period. Cumulative survival rates and the variation with time of lung function, the levels of immunoglobulins, and growth patterns were used as main outcome measures.
Results: Patients born during the screening programme but detected clinically appeared to have a reduced life expectancy compared with patients detected by screening. The patients detected by screening showed less deterioration in lung function (annual decrease 1.2% of FEV1 % pred), a smaller increase in immunoglobulin levels, and minimal catch-up growth compared with an annual decrease of 3.25% of FEV1 % pred in the non-screened birth cohort of the same age, a higher rise in immunoglobulins leading to increased levels at the end of the observation period, and catch-up growth for weight as well as height. Differences between patients treated in a cystic fibrosis centre and those not referred to a specialist centre were smaller but similar, in favour of treatment at a cystic fibrosis clinic.
Conclusions: Expert management started immediately after an early diagnosis of cystic fibrosis by neonatal screening results in important beneficial effects on the outcome and clinical course of the condition. The institution of very early treatment may be critical for the outcome and long term prognosis for most patients with cystic fibrosis. Neonatal screening programmes for cystic fibrosis should be introduced more widely.