1001 Rate of lung function deterioration in cystic fibrosis (CF)

An article written by staff of the CF clinic at the Red Cross Hospital in Cape Town and published in the SA Journal of Child Health deals with rate of decline in pulmonary function and its relationship to mortality in CF sufferers. The research not only makes an excellent case for longitudinal monitoring and recording of data, but also for making use of the data in order to analyse and audit outcomes. The point is made that in developed countries the rate of lung function decline is predictable, with an annual rate of FEV1 decline of <2% for children born after 1980 (i.e. coincident with advances in medical and general patient care). However progression of disease is quicker in a developing country such as South Africa where factors such as pollution, disease and poor health services contribute. Given the relationship between decline in lung function and life expectancy, and the observation that median survival in the Western Cape is 20.5 years, based on historical overseas data it was anticipated that the annual rate of decline of FEV1 would be between 2 and 5% per annum. This aspect could be studied at the Red Cross Hospital patients because all CF patients over 5 years of age have had formal and repeated lung function tests for several years. 79 patients were included, median age at the first assessment was 7.98 years. Subjects had a mean of 14 measurements over the study period and 9 patients died (median age of death 16.8 years). Contrary to expectation, the authors found that the estimated FEV1 at 6 was 73.83% of predicted with an annual rate of decline of only 0.23% per annum. FEV1 at 6 was affected by age at diagnosis, genotype and year of birth, and rate of decline was affected by Pseudomonas aeruginosa colonization and by genotype. The authors relate the slower than expected decline in lung function to improved medical care, access to such care and social circumstances of patients, and while they anticipate concomitant improvements in life expectancy, they nevertheless caution that study numbers were small and also that the study group would need to be followed for much longer to correlate the rate of change to mortality.

Read more:
SA J Child Health 2009; 3: 73-7
Thorax 2006; 61: 155-7
J Cystic Fibrosis 2004; 3: S116