Early diagnosis from newborn screening maximises survival in severe cystic fibrosis

Abstract

Newborn screening (NBS) for cystic fibrosis (CF) has been gradually established in several countries, but scant data are available on its long-term effects on survival. Our objective was to evaluate the long-term effects of CF NBS on survival. 586 patients, diagnosed and followed between 1971 and 2014 at the Verona CF Centre were analysed. Eligibility was confirmed in 342 cases diagnosed by NBS, 101 with meconium ileus and 143 through symptoms (44 out of 143 were NBS false negatives). The primary end-point was the 30-year overall survival in patients diagnosed by NBS. Patients were grouped according to the number of hospitalisations for respiratory or nutritional symptoms in the first 3 years of life: 0 (mild), 1-2 (moderate) and ≥3 (severe). Survival in NBS and symptoms groups was compared. The 30-year survival probability of the NBS group was 80.1% (95% CI 71.4-86.4%); in the symptoms group it was 71.0% (95% CI 62.2-78.2%). The 20-year survival was significantly higher in the NBS versus symptoms group in the severe (85% versus 64%, p=0.007) and moderate (94% versus 86%, p=0.016) groups. An adjusted Cox-model estimation confirmed differences in both the groups. Poor outcome associated with early severe presentation of CF is tempered by NBS.

FIGURE 1

The 20-year overall survival was significantly higher in the newborn screening (NBS) group than in the symptoms group for each of the subgroups defined according to severity. In a) the severe group it was 85% in the NBS versus 64% in the symptoms group (p=0.007); in b) the moderate group it was 94% in the NBS versus 86% in the symptoms group (p=0.016); and in c) the mild group it was 98% in the NBS versus 93% in the symptoms group (p=0.6). Survival probability is presented on a scale from 0.5 to 1.0 for readability. HR: hazard ratio; OS: overall survival.