Global disparities in cystic fibrosis outcomes prior to CFTR modulators: A CF registries cohort study in South Africa and Canada

Marco Zampoli; Jenna Sykes; Janine Verstraete; Stephanie Y Cheng; Brenda Morrow; Michael S Pepper; Cheryl Stewart; Heather J Zar; Anne L Stephenson

doi:10.1016/j.jcf.2023.09.003

Global disparities in cystic fibrosis outcomes prior to CFTR modulators: A CF registries cohort study in South Africa and Canada

J Cyst Fibros. 2024 Mar;23(2):334-340. doi: 10.1016/j.jcf.2023.09.003. Epub 2023 Sep 12.

Authors

Marco Zampoli¹, Jenna Sykes², Janine Verstraete³, Stephanie Y Cheng⁴, Brenda Morrow³, Michael S Pepper⁵, Cheryl Stewart⁶, Heather J Zar⁷, Anne L Stephenson²

Affiliations

¹ Department of Paediatrics and Child Health, University of Cape Town, South Africa; South African MRC Unit for Child and Adolescent Health, University of Cape Town, South Africa. Electronic address: m.zampoli@uct.ac.za.
² Department of Respirology, Adult Cystic Fibrosis Program, St. Michael's Hospital, University of Toronto, Toronto, Canada.
³ Department of Paediatrics and Child Health, University of Cape Town, South Africa.
⁴ Cystic Fibrosis Canada, Toronto, Canada.
⁵ Department of Immunology, Institute for Cellular and Molecular Medicine, SAMRC Extramural Unit for Stem Cell Research and Therapy, University of Pretoria, South Africa.
⁶ Department of Basic Medical Sciences, The University of the West Indies, Mona, Jamaica.
⁷ Department of Paediatrics and Child Health, University of Cape Town, South Africa; South African MRC Unit for Child and Adolescent Health, University of Cape Town, South Africa.

PMID: 37704465
DOI: 10.1016/j.jcf.2023.09.003

Abstract

Background: Outcomes of cystic fibrosis (CF) differ between low-middle income and high-income countries, but comparative data are lacking. We compared South African (SA) and Canadian CF outcomes to explore what disparities existed prior to access of CFTR modulators in Canada.

Methods: A cross-sectional study of SA and Canadian CF registries data for period 1 January to 31 December 2018. CF registry data were harmonised between countries to compare lung function and nutrition outcomes. Poor nutrition was defined as BMIz-score < -1 in children and < 18.5 kg/m² in adults. Standardised mean difference (SMD) >10 was considered significant.

Results: After excluding Canadians on CFTR modulators and lung transplant recipients, data on 4049 Canadian and 446 SA people was analysed. Compared to Canada, people in SA were younger (median age 15.8 years vs. 24.1 years: SMD 52) with fewer males (47.8% vs 54.2%; SMD 12.5) and White (70.9% vs. 93.3%; SMD 61.3). Class I-III CFTR mutation frequency was similar in SA (n = 384, 86.1%) and Canada (n = 3426, 84.9%). After adjusting for age, gender, diagnosis age, genotype, P.aeruginosa infection and pulmonary treatments, FEV1pp was 8.9% lower (95% CI 6.3% to 11.4%) and poor nutrition 1.7-fold more common (OR 1.70; 95% CI 1.19-2.41) in SA compared to Canada.

Conclusion: Lung function and nutrition was significantly lower in SA compared to Canada. Global disparities in CF outcomes between high and low-middle income countries are likely to widen as CFTR modulators are rapidly scaled up in only high-income countries.

Keywords: Canada; Cystic fibrosis; Outcome disparities; South Africa.

MeSH terms

Adolescent
Adult
Canada / epidemiology
Child
Cohort Studies
Cross-Sectional Studies
Cystic Fibrosis Transmembrane Conductance Regulator* / genetics
Cystic Fibrosis* / drug therapy
Cystic Fibrosis* / epidemiology
Cystic Fibrosis* / genetics
Cystic Fibrosis* / physiopathology
Female
Healthcare Disparities / statistics & numerical data
Humans
Male
Registries*
South Africa / epidemiology
Young Adult