Early lung disease in cystic fibrosis

Spirometry, and in particular the forced expiratory volume in 1 second (FEV1) measurement, has long been the yardstick by which lung disease in cystic fibrosis (CF) has been measured. However, it is only as reliable as the ability of the child to use the spirometer correctly: children under 6 years are often assumed to lack the necessary skills. Low FEV1s from young children's first efforts at using the spirometer are often attributed to ‘poor technique’. A study from Arkansas, US, suggests that a low FEV1 at age 6 should be taken seriously (Com G and colleagues. J Pediatr 2014;164:832–8). They divided their clinic population retrospectively into a group of 21 whose first FEV1 at age 6–7 years was low (mean 69% predicted), and 101 in whom it was high (mean 95% predicted). Most had not been diagnosed by screening (mean age at diagnosis 4 months). They then tracked both groups over a mean of 6 or 8 years of follow-up. The low FEV1s did not improve, but slowly declined: however, the rate of decline was significantly faster in the high FEV1 group. The low FEV1 group were less well nourished, and had higher rates of Pseudomonas colonisation.

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