Cochrane review: Newborn screening for cystic fibrosis

Background

Does newborn screening for cystic fibrosis (CF) improve clinical outcomes, quality of life and survival?

Objectives

To examine whether newborn screening for CF prevents or reduces irreversible organ damage and improves clinical outcomes, quality of life and survival in people with CF without unacceptable adverse effects.

Search strategy

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from electronic database searches, handsearches of relevant journals and abstract books of conference proceedings.

The Group's Trials Register last searched: June 2008.

Selection criteria

Randomised or quasi-randomised controlled trials, published and unpublished, comparing screening to clinical diagnosis in people with CF.

Data collection and analysis

Two authors independently assessed trial eligibility and quality and independently extracted data. Allocation concealment was unclear in both studies and sequence generation adequate in one.

Main results

Searches identified six trials. Two trials involving 1,124,483 neonates (210 with CF) with a maximum follow up of 17 years were eligible for inclusion. Varying study designs, outcomes reported and summary measures precluded calculation of pooled estimates and only data from one study were analysed. Severe malnutrition was less common among screened participants. Compared with screened participants, the odds ratio of weight below the tenth percentile was 4.12 (95% CI 1.64 to 10.38) and for height was 4.62 (95% CI 1.69 to 12.61) in the control group.

At age seven, 88% of screened participants and 75% of controls had lung function parameters within normal limits of at least 89% predicted. At diagnosis chest radiograph scores were significantly better among screened participants; 33% of screened versus 50% of control participants had Wisconsin chest X-ray (WCXR) scores over five (P = 0.097) and 24% of screened versus 45% of control participants had Brasfield chest X-ray (BCXR) scores under 21 (P = 0.042)). Over time, chest radiograph scores were worse in the screened group (WCXR P = 0.017 and BCXR P = 0.041). Results were no longer significant after adjustment for genotype, pancreatic status, and Pseudomonas aeruginosa-culture results. In screened participants colonisation with Pseudomonas aeruginosa occurred earlier. Estimates suggest diagnosis through screening is less expensive.

Authors' conclusions

Two randomised controlled trials assessing neonatal screening in CF were identified; data from one study were included. Nutritional benefits are apparent. Screening provides potential for better pulmonary outcomes, but confounding factors influenced long-term pulmonary prognosis of people with CF. Screening seems less expensive than traditional diagnosis.

Plain Language Summary

Screening newborn babies for cystic fibrosis

In people with cystic fibrosis lung disease and malnutrition occur very early in life. These complications are suited to early treatment. Newborn screening may therefore improve outcomes for people with cystic fibrosis. We aimed to find out whether newborn screening prevents or reduces organ damage and improves clinical outcomes in people with CF without unacceptable adverse effects. This review includes two trials with 1,124,483 babies (210 with cystic fibrosis). The trials compared newborn screening to clinical diagnosis. We were only able to analyse data from one of the trials. This trial showed that severe malnutrition was less common among screened babies. Screened babies had better chest radiograph scores at diagnosis, but these scores became worse over time. The screened babies become colonised with Pseudomonas aeruginosa earlier. Costs for screening were less than costs for traditional diagnosis.