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

• Lung function and nutrition prior to CFTR modulator therapy was significantly lower in people with CF in south Africa compared to Canada. • Disparities in outcomes are likely due to different socioeconomic conditions, inferior quality of healthcare in SA and early-life determinants of health. • Global disparities in CF outcomes between high and low to middle income countries are likely to widen in future as CFTR modulators rapidly become standard of care in only high-income countries. 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. 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. 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. 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. [ABSTRACT FROM AUTHOR]