Disparities in cystic fibrosis survival in Mexico: Impact of socioeconomic status

Standards for the care of people with cystic fibrosis (CF); Planning for a longer life

This is the final of four papers updating standards for the care of people with CF. That this paper "Planning a longer life" was considered necessary, highlights how much CF care has progressed over the past decade. Several factors underpin this progress, notably increased numbers of people with CF with access to CFTR modulator therapy. As the landscape for CF changes, so do the hopes and aspirations of people with CF and their families. This paper reflects the need to consider people with CF not as a "problem" to be solved, but as a success, a potential and a voice to be heard. People with CF and the wider CF community have driven this approach, reflecting many of the topics in this paper. This exercise involved wide stakeholder engagement. People with CF are keen to contribute to research priorities and be involved in all stages of research. People with CF want healthcare professionals to respect them as individuals and consider the impact of our actions on the world around us. Navigating life presents challenges to all, but for people with CF these challenges are heightened and complex. In this paper we highlight the concerns and life moments that impact people with CF, and events that the CF team should aim to support, including the challenges around having a family. People with CF and their care teams must embrace the updated standards outlined in these four papers to enjoy the full potential for a healthier life.

CFTR pathogenic variants spectrum in a cohort of Mexican patients with cystic fibrosis

Background

Molecular diagnosis of cystic fibrosis (CF) is challenging in Mexico due to the population's high genetic heterogeneity. To date, 46 pathogenic variants (PVs) have been reported, yielding a detection rate of 77%. We updated the spectrum and frequency of PVs responsible for this disease in mexican patients.

Methods

We extracted genomic DNA from peripheral blood lymphocytes obtained from 297 CF patients and their parents. First, we analyzed the five most frequent PVs in the Mexican population using PCR-mediated site-directed mutagenesis. In patients with at least one identified allele, CFTR sequencing was performed using next-generation sequencing tools and multiplex ligation-dependent probe amplification. For variants not previously classified as pathogenic, we used a combination of in silico prediction, CFTR modeling, and clinical characteristics to determine a genotype-phenotype correlation.

Results

We identified 95 PVs, increasing the detection rate to 87.04%. The most frequent variants were p.(PheF508del) (42.7%), followed by p.(Gly542*) (5.6%), p.(Ser945Leu) (2.9%), p.(Trp1204*) and p.(Ser549Asn) (2.5%), and CFTRdel25-26 and p.(Asn386Ilefs*3) (2.3%). The remaining variants had frequencies of <2.0%, and some were exclusive to one family. We identified 10 novel PVs localized in different exons (frequency range: 0.1-0.8%), all of which produced structural changes, deletions, or duplications in different domains of the protein, resulting in dysfunctional ion flow. The use of different in silico software and American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) criteria allowed us to assume that all of these PVs were pathogenic, causing a severe phenotype.

Conclusions

In a highly heterogeneous population, combinations of different tools are needed to identify the variants responsible for CF and enable the establishment of appropriate strategies for CF diagnosis, prevention, and treatment.

Epithelial-Mesenchymal Transition Mechanisms in Chronic Airway Diseases: A Common Process to Target?

Epithelial-to-mesenchymal transition (EMT) is a reversible process, in which epithelial cells lose their epithelial traits and acquire a mesenchymal phenotype. This transformation has been described in different lung diseases, such as lung cancer, interstitial lung diseases, asthma, chronic obstructive pulmonary disease and other muco-obstructive lung diseases, such as cystic fibrosis and non-cystic fibrosis bronchiectasis. The exaggerated chronic inflammation typical of these pulmonary diseases can induce molecular reprogramming with subsequent self-sustaining aberrant and excessive profibrotic tissue repair. Over time this process leads to structural changes with progressive organ dysfunction and lung function impairment. Although having common signalling pathways, specific triggers and regulation mechanisms might be present in each disease. This review aims to describe the various mechanisms associated with fibrotic changes and airway remodelling involved in chronic airway diseases. Having better knowledge of the mechanisms underlying the EMT process may help us to identify specific targets and thus lead to the development of novel therapeutic strategies to prevent or limit the onset of irreversible structural changes.

Socioeconomic determinants of respiratory health in patients with cystic fibrosis: implications for treatment strategies

INTRODUCTION

Great variation exists in the progression and outcomes of cystic fibrosis (CF) lung disease, due to both genetic and environmental influences. Social determinants mediate environmental exposures and treatment success; people with CF from socioeconomically disadvantaged backgrounds have worse health and die younger than those in more advantaged positions.

AREAS COVERED

This paper reviews the literature on the mechanisms that are responsible for generating and sustaining disparities in CF health, and the ways by which social determinants translate into health advantages or disadvantages in people with CF. The authors make recommendations for addressing social risk factors in CF clinical practice.

EXPERT OPINION

Socioeconomic factors are not dichotomous and their impact is felt at every step of the social ladder. CF care programs need to adopt a systematic protocol to screen for health-related social risk factors, and then connect patients to available resources to meet individual needs. Considerations such as daycare, schooling options, living and working conditions, and opportunities for physical exercise and recreation as well as promotion of self-efficacy are often overlooked. In addition, advocacy for changes in public policies on health insurance, environmental regulations, social welfare, and education would all help address the root causes of CF health inequities.

Trends in cystic fibrosis survival over 40 years in South Africa: An observational cohort study

INTRODUCTION

Temporal trends in cystic fibrosis (CF) survival from low-middle-income settings is 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 2000 (vs. 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 Pseudomonas aeruginosa (PA) infection. A second analysis explored the association of mortality with weight and forced expiratory volume in 1 s reported as z-scores (FEV1z-scores) at age 5-8 years.

RESULTS

A total of 288 people (52% male; 57% Caucasian; 44% p.Phe508del homozygous) were included (median diagnosis age 0.5 years: Q1, Q3: 0.2, 2.5); 100 (35%) died and 30 (10%) lost to follow-up. Among age >10 years, age-specific mortality from 2000 was significantly lower (adjusted hazard ratio [aHR]: 0.14; 95% confidence interval [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 longer times since first PA infection with higher mortality (aHR: 1.31; 95% CI: 1.01, 1.68). Mortality was sevenfold 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 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.