Beyond borders: cystic fibrosis survival between Australia, Canada, France and New Zealand

BACKGROUND

Life expectancy for people with cystic fibrosis (CF) varies considerably both within and between countries. The objective of this study was to compare survival among countries with single-payer healthcare systems while accounting for markers of disease severity.

METHODS

This cohort study used data from established national CF registries in Australia, Canada, France and New Zealand from 2015 to 2019. Median age of survival for each of the four countries was estimated using the Kaplan-Meier method. A Cox proportional hazards model was used to compare risk of death between Canada, France and Australia after adjusting for prognostic factors. Due to low number of deaths, New Zealand was not included in final adjusted models.

RESULTS

Between 2015 and 2019, a total of 14 842 people (3537 Australia, 4434 Canada, 6411 France and 460 New Zealand) were included. The median age of survival was highest in France 65.9 years (95% CI: 59.8 to 76.0) versus 53.3 years (95% CI: 48.9 to 59.8) for Australia, 55.4 years (95% CI: 51.3 to 59.2) for Canada and 54.8 years (95% CI: 40.7 to not available) for New Zealand. After adjusting for individual-level factors, the risk of death was significantly higher in Canada (HR 1.85, 95% CI: 1.48 to 2.32; p<0.001) and Australia (HR 2.08, 95% CI: 1.64 to 2.64; p<0.001) versus France.

INTERPRETATION

We observed significantly higher survival in France compared with countries with single-payer healthcare systems. The median age of survival in France exceeded 60 years of age despite having the highest proportion of underweight patients which may be due to differences in availability of transplant.

Cancer incidence and prevalence in cystic fibrosis patients with and without a lung transplant in France

Background

Cystic fibrosis (CF) care and the life expectancy of affected patients have substantially improved in recent decades, leading to an increased number of patients being diagnosed with comorbidities, including cancers. Our objective was to characterize the epidemiology of cancers between 2006 and 2017 in CF patients with and without a lung transplant.

Methods

Medical records of CF patients from 2006 to 2016 in the French CF Registry were linked to their corresponding claims data (SNDS). The annual prevalence and incidence rates of cancers were estimated from 2006 to 2017 in CF patients without lung transplant and in those with lung transplant after transplantation.

Results

Of the 7,671 patients included in the French CF Registry, 6,187 patients (80.7%) were linked to the SNDS; among them, 1,006 (16.3%) received a lung transplant. The prevalence of any cancer increased between 2006 and 2017, from 0.3 to 1.0% and from 1.3 to 6.3% in non-transplanted and transplanted patients, respectively. When compared to the general population, the incidence of cancer was significantly higher in both non-transplanted [Standardized Incidence Ratio (SIR) = 2.57, 95%CI 2.05 to 3.17] and transplanted (SIR = 19.76, 95%CI 16.45 to 23.55) patients. The median time between transplant and the first cancer was 3.9 years. Among the 211 incident cancer cases, the most frequent malignant neoplasms were skin neoplasm (48 cases), lung cancers (31 cases), gastro-intestinal (24 cases), and hematologic cancers (17 cases).

Conclusion

The overall burden of cancer in CF patients is high, particularly following lung transplantation. Therefore, specific follow-up, screening and cancer prevention for CF patients with transplants are necessary.

Cumulative Incidence and Risk Factors for Severe COVID-19 in French People with Cystic Fibrosis

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are closely monitored in people with cystic fibrosis (pwCF), with a special emphasis on severe cases. Previous studies used hospitalization rates as proxy for severity.

Methods

We evaluated data from coronavirus disease 2019 (COVID-19) cases diagnosed in French pwCF followed in one of the 47 French CF center over the first year of the pandemic.

Objective

criteria were applied for defining severity (e.g., respiratory failure and/or death). Data were compared to those from all French pwCF using the French CF Registry.

Results

As of April 30, 2021, 223 pwCF were diagnosed with COVID-19, with higher risks in adults (≥18 years, odds ratio [OR] = 2.52, 95% confidence interval [CI] = 1.82-3.48) and post-transplant individuals (OR = 2.68, 95% CI = 1.98-3.63). Sixty (26.9%) patients were hospitalized, with an increased risk in post-transplant individuals (OR = 4.74, 95% CI = 2.49-9.02). In 34 (15%) cases, COVID-19 was considered severe; 28/60 (46.7%) hospitalizations occurred in patients without objective criteria of severity. Severe cases occurred mostly in adults (85.3%) and post-transplant pwCF (61.8%, OR = 6.02, 95% CI = 2.77-13.06). In non-transplanted pwCF, risk factors for severity included low lung function (median ppFEV₁ 54.6% vs. 75.1%, OR = 1.04, 95% CI = 1.01-1.08) and CF-associated diabetes (OR = 3.26, 95% CI = 1.02-10.4). While most cases recovered without sequelae (n = 204, 91.5%), 16 (13%) were followed for possible sequelae, and three post-transplant females died.

Conclusions

Severe COVID-19 cases occurred infrequently during the first year of the pandemic in French pwCF. Non-transplanted adults with severe respiratory disease or diabetes and post-transplant individuals were at risk for severe COVID-19. Thus, specific preventive measures should be proposed.

The impact of the high emergency lung transplantation program in cystic fibrosis in France: insight from a comparison with Canada

INTRODUCTION

France implemented a high emergency lung transplantation (HELT) program nationally in 2007. A similar program does not exist in Canada. The objectives of our study were to compare health outcomes within France as well as between Canada and France before and after the HELT program in a population with Cystic Fibrosis (CF).

METHODS

This population-based cohort study utilised data from the French and Canadian CF registries. A cumulative incidence curve assessed time to transplant with death without transplant as competing risks. The Kaplan-Meier method was used to estimate post-transplant survival.

RESULTS

Between 2002 and 2016, there were 1075 (13.0%) people with CF in France and 555 (10.2%) people with CF in Canada who underwent lung transplantation. The proportion of lung transplant increased in France after the HELT program was initiated (4.5% versus 10.1%) whereas deaths pre-transplant decreased from 85.3% in the pre-HELT to 57.1% in the post-HELT period. Between 2008-2016, people in France were significantly more likely to receive a transplant (Hazard Ratio (HR) 1.56, 95% CI 1.37-1.77, p<0.001) than die (HR 0.55, 95% CI 0.46-0.66, p<0.001) compared to Canada. Post-transplant survival was similar between the countries and there was no difference in survival when comparing pre- and post-HELT period in France.

CONCLUSION

Following the implementation of the HELT program, people living with CF in France were more likely to receive a transplant than die. Post-transplant survival in the post-HELT period in France did not change compared to the pre-HELT period, despite potentially sicker patients being transplanted, and is comparable to Canada.

Cluster and CART analyses identify large subgroups of adults with cystic fibrosis at low risk of 10-year death

Our goal was to identify subgroups of adults with cystic fibrosis (CF) at low risk of death within 10 years.Factor analysis for mixed data followed by Ward's cluster analysis was conducted using 25 variables from 1572 French CF adults in 2005. Rates of death by subgroups were analysed over 10 years. An algorithm was developed using CART (classification and regression tree) analysis to provide rules for the identification of subgroups of CF adults with low rates of death within 10 years. This algorithm was validated in 1376 Canadian CF adults.Seven subgroups were identified by cluster analysis in French CF adults, including two subgroups with low (∼5%) rates of death at 10 years: one subgroup (22% of patients) was composed of patients with nonclassic CF, the other subgroup (17% of patients) was composed of patients with classic CF but low rates of Pseudomonas aeruginosa infection and diabetes. An algorithm based on CART analysis of data in 2005 allowed us to identify most French adults with low rates of death. When tested using data from Canadian CF adults in 2005, the algorithm identified 287 out of 1376 (21%) patients at low risk (10-year death: 7.7%).Large subgroups of CF adults share low risk of 10-year mortality.

Clinical and microbiological characteristics of cystic fibrosis adults never colonized by Pseudomonas aeruginosa: Analysis of the French CF registry

Pseudomonas aeruginosa is the main cause of chronic airway infection in cystic fibrosis (CF). However, for unclear reasons some patients are never colonized by P. aeruginosa. The objectives of this study were to better define the clinical, genetic, and microbiological characteristics of such a subpopulation and to identify predictive factors of non-colonization with P. aeruginosa. The French CF patient registry 2013–2014 was used to identify CF patients aged ≥ 20 years. The clinical outcomes, CF Transmembrane conductance Regulator (CFTR) genotypes, and microbiological data of patients reported positive at least once for P. aeruginosa (“Pyo” group, n = 1,827) were compared to those of patients with no history of P. aeruginosa isolation (“Never” group, n = 303). Predictive factors of non-colonization by P. aeruginosa were identified by multivariate logistic regression model with backward selection. Absence of aspergillosis (odds ratio (OR) [95% CI] = 1.64 [1.01–2.66]), absence of diabetes (2.25 [1.21–4.18]), pancreatic sufficiency (1.81 [1.30–2.52]), forced expiratory volume 1 (FEV1) ≥ 80% (3.03 [2.28–4.03]), older age at CF diagnosis (1.03 [1.02–1.04]), and absence of F508del/F508del genotype (2.17 [1.48–3.19]) were predictive clinical factors associated with absence of infection (“Never” group). Microbiologically, this same group was associated with more frequent detection of Haemophilus influenzae and lower rates of Stenotrophomonas maltophilia, Achromobacter xylosoxidans and Aspergillus spp. (all p<0.01) in sputum. This study strongly suggests that the absence of pulmonary colonization by P. aeruginosa in a minority of CF adults (14.2%) is associated with a milder form of the disease. Recent progress in the development of drugs to correct CFTR deficiency thus may be decisive in the control of P. aeruginosa lung infection.

Quality of care in cystic fibrosis: assessment protocol of the French QIP PHARE-M

BACKGROUND

The PHARE-M care quality improvement program, modeled on the US Cystic Fibrosis Quality Improvement Program, was introduced at 14 cystic fibrosis centers (CFCs) in the French Cystic Fibrosis Network between 2011 and 2013. The pilot phase assessments attested the progressive adherence of the teams and improvements in care management. The PHARE-M Performance research project aims at assessing in 2015 the impact of the PHARE-M program on patient health indicators at trained versus untrained centers. It also sought to identify contextual factors that could account for variability in the performance of the PHARE-M among the trained centers.

METHODS

A mixed methodology combining: a quantitative experimental study: a comparison, using a mixed model for repeated data (from 2011 to 2015), of the average changes over time in forced expiratory volume in 1 s (FEV1) and body mass index (BMI) between two groups of patients included in a closed cohort (non-transplant patients, continuous follow-up at one participating CFC, and a CF-causing mutation), one having benefitted from the PHARE-M program and the other not having done so, and a realistic study: a characterization of the impact on care management and an identification of mechanisms through which the PHARE-M intervention improved the team's effectiveness in different CFC contexts; this required modeling the intervention, context, and impact on care management with respect to the criteria of the chronic care model (CCM); this was done using a self-administered questionnaire given to professionals and patients/parents supplemented with focus groups.

CONCLUSION

Although the study population was controlled, it may be difficult to establish a causal relationship between the differences in the changes over time in patient health indicators in the two groups of patients and the PHARE-M intervention as it is often the case in complex interventions rolled out in adaptive environments. The analysis of factors associated with variations in the impact of the PHARE-M at the different trained CFCs required the adoption of instruments validated in other contexts; these could be useful for assessing the performance of other interventions in healthcare practices at CFCs in France.

Retrospective observational study of French patients with cystic fibrosis and a Gly551Asp-CFTR mutation after 1 and 2years of treatment with ivacaftor in a real-world setting

BACKGROUND

Ivacaftor has been shown to improve lung function and body weight in patients with CF and a gating mutation. Real-world evaluation is warranted to examine its safety and effectiveness over the long term.

METHODS

A retrospective observational multicentre study collected clinical data in the year before and the 2years after ivacaftor initiation in patients with CF and a Gly551Asp-CFTR mutation.

RESULTS

Fifty-seven patients were included. Mean absolute change in FEV₁% predicted improved from baseline to Year 1 (8.4%; p<0.001) and Year 2 (7.2%; p=0.006). Statistically significant benefits were observed with increased body mass index, fewer Pseudomonas aeruginosa and Staphylococcus aureus positive cultures, and decreased IV antibiotics and maintenance treatment prescriptions (including azithromycin, Dornase alpha and nutritional supplements). No significant adverse events were reported.

CONCLUSION

The clinical benefits of ivacaftor reported in previous clinical trials were confirmed in a real-world setting two years post-initiation, also reducing treatment burden.