Survival of people with cystic fibrosis in Australia

Abstract

Survival statistics, estimated using data from national cystic fibrosis (CF) registries, inform the CF community and monitor disease progression. This study aimed to estimate survival among people with CF in Australia and to identify factors associated with survival. This population-based cohort study used prospectively collected data from 23 Australian CF centres participating in the Australian CF Data Registry (ACFDR) from 2005-2020. Period survival analysis was used to calculate median age of survival estimates for each 5-year window from 2005-2009 until 2016-2020. The overall median survival was estimated using the Kaplan-Meier method. Between 2005-2020 the ACFDR followed 4,601 people with CF, noting 516 (11.2%) deaths including 195 following lung transplantation. Out of the total sample, more than half (52.5%) were male and 395 (8.6%) had undergone lung transplantation. Two thirds of people with CF (66.1%) were diagnosed before six weeks of age or by newborn/prenatal screening. The overall median age of survival was estimated as 54.0 years (95% CI: 51.0-57.04). Estimated median survival increased from 48.9 years (95% CI: 44.7-53.5) for people with CF born in 2005-2009, to 56.3 years (95% CI: 51.2-60.4) for those born in 2016-2020. Factors independently associated with reduced survival include receiving a lung transplant, having low FEV₁pp and BMI. Median survival estimates are increasing in CF in Australia. This likely reflects multiple factors, including newborn screening, improvement in diagnosis, refinements in CF management and centre-based multidisciplinary care.

Figure 1

(A) Overall survival curve for people with cystic fibrosis, based on Kaplan–Meier estimates. (B) Probability functions depicting the age of people with cystic fibrosis by diagnosis category (with meconium ileus symptoms, under < 6 weeks or by NBS/prenatal screening, 6 weeks – < 2 years, 2–17 years and ≥ 18 years groups). (C) Probability functions depicting the age of people with CF by average lifetime lung function (FEV1 pp categories ≥ 70, 40–69, < 40). (D) Probability functions depicting the age of people with cystic fibrosis by BMI. Adult individuals (≥ 8 years) were classified into BMI categories based on World Health Organization guidelines as underweight (< 18.5 kg/m²), adequate weight (18.5–24.9 kg/m²), or overweight (≥ 25.0 kg/m²). Children were classified as underweight (< 10th percentile), adequate weight (10–85th percentile), or overweight (> 85th percentile).

Figure 2

Median survival of people with cystic fibrosis in Australia (5-year cohorts), 2005–2020. Black circles indicate median age data. Error bars represent 95% confidence intervals data. Summary statistics are provided in Table 3.