Lung function decline is accelerated in South Africans with cystic fibrosis

Abstract

Background: Poor nutritional status has been shown to be associated with a significant decline in lung function in patients with cystic fibrosis. There are few data published on the lung function decline and the effects of nutritional status in cystic fibrosis (CF) in South Africa.

Aim: To assess anthropometric parameters (weight, height, body mass index Z-score) in relation to lung function parameters in CF patients.

Methodology: A retrospective chart review of clinical records of participants over the age of five years attending the CF clinic at Steve Biko Academic Hospital from 2005 to 2010.

Results: Twenty files were reviewed for lung function, anthropometric measurements, gender and CF-causing mutations. For anthropometric measurements the average changes were –0.8, –0.5 and 2.0 for weight, BMI and height Z-scores, respectively. A decline in FEV₁ of –25.3 (95% CI 39.4; –13.3) over the five-year period was noted, with an average decline of 5.3% per year. For FEF_25-75, the average change was –22.4 (95% CI-34.6; –10.2) with a decline of 4.5% per year. Using multivariate analysis, the FEV₁ was found to be significantly influenced by: age –3.96 (95% CI –7.4; –0.5); p = 0.03, weight 1.8 (95% CI –3.4; –0.9); p = 0.04, BMI Z-score 4.3 (95% CI 5.3; 23.3); p = 0.02 and gender (p = 0.02). The FEF_25-75 was significantly influenced by BMI Z-score and gender.

Conclusion: The average lung function decline per year for FEV₁ was higher than that seen in developed countries. The decline in FEV₁ was related to gender, age, weight and BMI. The decline in FEF_25-75 was affected only by BMI Z-score and gender.