Impact of inhaled corticosteroids on the risk of early Pseudomonas aeruginosa acquisition in cystic fibrosis

Aim: To investigate the role of inhaled corticosteroids (IC) on the risk of Pseudomonas aeruginosa acquisition before the age of 10 y in cystic fibrosis (CF) patients. Methods: For each subject the cumulative dose kg^-1 of IC received for each year of age was calculated until the end of follow-up. The age at CF diagnosis, the nutritional status (NS) and the number of respiratory exacerbations (RE) were used as surrogate measures for the severity of CF. Results: A total of 83 patients (40 M, 43 F) entered the study. Their median length of follow-up was 4.4 y, for a total of 386 person-years at risk. Twenty-three patients acquired P. aeruginosa at a median age of 4.6 y (range 0.4-9.9 y). The estimated survival without P. aeruginosa acquisition was 65% at 10 y of age. The effect of different risk factors (IC, NS, RE and age at CF diagnosis) on the probability of P. aeruginosa acquisition was evaluated: none of them was significantly associated with the risk of P. aeruginosa acquisition. In particular, patients receiving very high cumulative doses of IC (4th quartile) had a non-significantly increased risk of P. aeruginosa acquisition compared with those receiving low doses of IC (1st quartile) (hazard ratio = 1.73, 95% confidence limits 0.40-7.38). Conclusion: This retrospective study was not able to demonstrate any role of IC in increasing the risk of P. aeruginosa acquisition. This complication seems to occur at a constant pace that is independent of CF severity and age. Prospective multi-institutional randomized studies are needed to investigate the effects of high-dose IC in CF patients.