Lung function in children with cystic fibrosis: A comparison between the UK and the US

Dr Anoushka de Almeida-Carragher, Senior Research Manager at the Trust looks at the recent discussion around the differences in average lung function between CF children here in the UK and those in the US.

In September last year, a paper was published in the journal ‘Thorax’, which reported that the average lung function in children and young adults with cystic fibrosis (CF) in the US was significantly better compared with those in the UK. The study was conducted by Christopher Goss and colleagues, based in the US and the UK. They collected data from the UK and US Registries and compared CF outcomes and the use of treatments.

The results of this study have undoubtedly raised some concerns, especially among some CF researchers in the UK. One issue is the fact that the UK Registry is more representative of the whole UK CF population (who have universal access to care via the NHS), whereas the US’s Registry only captures data of patients attending accredited CF centres. As a consequence, the UK’s data may show info from more disadvantaged socio-economic groups resulting in poorer clinical outcomes, compared with the US.

The paper does not explore the reasons, in great depth, behind the difference in lung function, but it does suggest that in the UK, chronic pulmonary therapies (like sterile hypertonic saline solution which helps clear mucus from the lungs) had been used much less frequently to treat young people compared to the US. They also speculate that the difference could be due to the difference in frequency of visits to CF centres; in the US, CF is only treated at specialist centres, while in the UK, care is managed between local hospitals and specialised units, and in some parts of the UK, young patients may only visit a specialist centre as little as once a year and then visit their local hospital the rest of the time, where they may not be seen by a CF practitioner.

What we can conclude is that making comparisons between one country and another is useful and informative, especially where there are obvious differences in care and treatment methods. Even though the results of this study show a lung function discrepancy between the two countries, the explanations for such differences are not definitive. Further investigations, such as cross-country longitudinal studies using Registry data, on a like-for-like basis, are essential before we can draw conclusions between treatments and outcomes in the global CF population.

You can learn more about research into cystic fibrosis at www.cysticfibrosis.org.uk/research