Cystic fibrosis in South Africa: spectrum of disease and determinants of outcome

Abstract

Introduction Little is known about cystic fibrosis (CF) in low- to middle-income settings. This study aimed to describe the spectrum and outcomes of CF in South Africa (SA) from the recently established SA CF registry (SACFR). Methods Demographic, diagnosis and clinical data were extracted from the SACFR. Cross-sectional univariable and multivariable regression analysis of best forced expiratory volume in 1 s (FEV1; age≥6 years) and nutrition (all ages) in 2018 was conducted to investigate factors associated with severe lung disease (SLD; FEV1 ≤3.0 z-score) and undernutrition. Results By December 2018, ancestry of 447 individuals included in the SACFR was Caucasian (315; 70%), mixed (87; 19%) and black African (41; 9%). Median diagnosis age was 7.6 months (IQR 2.7–37.1). Genotype was p.Phe508del homozygous (220; 49%); p.Phe508del heterozygous (144; 32%) and neither p.Phe508del or unknown Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) variant in 83 (19%); the second most frequent CFTR variant was 3120+1G>A, common in black Africans. Median age of patients in 2018 was 14.7 years (IQR 7.4–24.4). SLD was independently associated with chronic methicillin-resistant Staphylococcus aureus (MRSA) (adjusted odds ratio( aOR) 16.75; 95% CI 1.74–161.50), undernutrition (aOR 5.20; 95% CI 2.23–12.13) and age (aOR 2.23 per 10 years; 95% CI 1.50–3.31). Undernutrition was associated in univariable analysis with low weight at diagnosis, non-Caucasian ancestry, chronic P. aeruginosa infection and lower socioeconomic status. Conclusion Interventions targeting MRSA infection and nutrition are needed to improve CF outcomes in SA. Most people with CF in SA are eligible for highly effective CFTR modulator therapy.