Easy measurement of health related quality of life in patients with cystic fibrosis by the COPD assessment test (CAT) - A pilot study.

Background: Quality of life (QOL) is an important patient-related outcome (PRO) in patients with cystic fibrosis (CF). There are several QOL questionnaires like the "Cystic Fibrosis Questionnaire Revised" (CFQ-R) or the "St George's Respiratory Questionnaire" (SGRQ) that are well validated in CF. The aim of the study was to evaluate whether the easily applicable "COPD assessment test" (CAT) can be used in CF patients.

Methods: 42 CF patients were recruited within the PulmoHOM study, a prospective, observational cohort study. The CAT, the SGRQ and the CFQ-R were handed out to the patients. The spearman's rank correlation coefficient and the Cronbach's α coefficient were used for the statistical analysis.

Results: The internal consistencies of the CAT, SGRQ and the CFQ-R were high (Cronbach's α coefficients = 0.89, 0.91 and 0.83). There were significant correlations between the CAT and the total score of the SGRQ (r = 0.851, p < 0.01), between the CAT and many items of the CFQ-R (physical score of the CFQ-R and total score of the CAT: r = -0.872, p < 0.01) and between the SGRQ and the CFQ-R (physical score of the CFQ-R and total score of the SGRQ: r = -0.878, p < 0.01).

Conclusion: The main finding was the high correlation between the CAT and the validated questionnaires in CF. The CAT is a PRO instrument that can be filled quickly and that correlates well with the CFQ-R. The CAT or similar tools might be applicable in the care of CF patients.