Trends in Cystic Fibrosis survival over 40 years in South Africa: an
observational cohort study
Abstract
Introduction: Temporal trends in CF survival from low-middle-income
settings are poorly reported. We describe changes in CF survival after
diagnosis over 40 years from a South African (SA) CF center. Methods: An
observational cohort study of people diagnosed with CF from 1974 to
2019. Changes in age-specific mortality rates from the year 2000 (versus
before 2000) were estimated using multivariable Poisson regression. Data
were stratified by current age < or ≥ 10 years and models
controlled for diagnosis age, sex, ethnicity, genotype, and P.
aeruginosa (PA) infection. A second analysis explored association of
mortality with weight and FEV1z-scores at age 5-8 years. Results: 288
people (52% male; 57% Caucasian; 44% p.Phe508del homozygous) were
included (median diagnosis age 0.5 years: Q1,Q3: 0.2, 2.5); 58 (35%)
died and 30 (10%) lost to follow-up. Among age >10 years,
age-specific mortality from year 2000 was significantly lower (adjusted
hazard ratio aHR: 0.14; 95% CI: 0.06,0.29; p<0.001), but not
among age <10 years (aHR: 0.67; 95% CI: 0.28,1.64; p=0.383).
In children <10 years, Caucasian ethnicity was associated with
lower mortality (aHR 0.17; 95% CI 0.05,0.63), and time since first PA
infection with higher mortality (aHR 1.31; 95% CI 1.01,1.68). Mortality
was 7-fold higher if FEV1z was < -2.0 at age 5-8 years (aHR
7.64; 95% CI 2.58,22.59). Conclusion: Overall, CF survival has
significantly improved in SA from year 2000 in people older than 10
years. However, increased risk of mortality persists in young
non-Caucasian children, and with FEV1z<-2.0 at age 5-8 years.