Newborn screening for cystic fibrosis in Alberta: Two years of experience

Contemporary cystic fibrosis incidence rates in Canada and the United States

BACKGROUND

The availability of new diagnostic algorithms for cystic fibrosis (CF), changing population demographics and programs that impact family planning decisions can influence incidence rates. Thus, previously reported incidence rates in Canada and the United States (US) may be outdated. The objectives of this study were to estimate contemporary CF incidence rates in Canada and the US and to determine if the incidence rate has changed over time.

METHOD

This population-based cohort study utilized data between 1995-2019 from the Canadian CF Registry (CCFR), Statistics Canada, US CF Foundation Patient Registry (CFFPR) data, and US Center for Disease Control (CDC) National Vital Statistics System. Incidence was estimated using the number of live CF births by year, sex, and geographic region using Poisson regression, with the number of live births used as the denominator. To account for delayed diagnoses, we imputed the proportion of diagnoses expected given historical trends, and varying rates of newborn screening (NBS) implementation by region.

RESULTS

After accounting for implementation of NBS and delayed diagnoses, the estimated incidence rate for CF in 2019 was 1:3848 (95% CI: 1:3574, 1:4143) live births in Canada compared to 1:5130 (95% CI:1:4996, 1:5267) in the US. There was substantial regional variation in incidence rates within both Canada and the US. Since 1995, incidence rates have decreased at a rate of 1.6% per year in both countries (p<0.001).

CONCLUSION

Contemporary CF incidence rates suggest CF incidence is lower than previously reported and varies widely within North America. This information is important for resource planning and for tracking how programs (e.g., genetic counselling, modulator availability etc.) may impact the incidence of CF moving forward.

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.

Toward a Broader Understanding of Cystic Fibrosis Epidemiology and Its Impact on Clinical Manifestations

The incidence of cystic fibrosis remains constant in North America and Western Europe is 1 in 3500 live births, but survival and quality of life have improved. The cystic fibrosis population has shifted toward the adult age range with a concomitant shift in the spectrum of complications. Survival increased because of aggressive symptomatic therapy, earlier diagnosis by newborn screening, and the introduction of modulators of the cystic fibrosis transmembrane conductance regulator, so that predicted median survival age is now about 50 years. In the United States, members of low socioeconomic status populations or members of racial or ethnic minorities have benefitted less from these advances.

The Changing Face of Cystic Fibrosis: An Update for Anesthesiologists

Cystic fibrosis (CF) is the most common fatal genetic disease in North America. While CF is more common among Whites, it is increasingly being recognized in other races and ethnicities. Although there is no cure, life expectancy has steadily improved, with the median survival exceeding 46 years in the United States. There are now more adults than children with CF in the United States. CF is caused by mutations in a gene that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein, expressed in many epithelial cells. More than 2100 CFTR mutations have been linked to CF, and newer CFTR modulator drugs are being used to improve the production, intracellular processing, and function of the defective CFTR protein. CF is a multisystem disease that affects primarily the lungs, pancreas, hepatobiliary system, and reproductive organs. Anesthesiologists routinely encounter CF patients for various surgical and medical procedures, depending on the age group. This review article focuses on the changing epidemiology of CF, advances in the classification of CFTR mutations, the latest innovations in CFTR modulator therapies, the impact of the coronavirus disease pandemic, and perioperative considerations that anesthesiologists must know while caring for patients with CF.

The Changing Epidemiology of Cystic Fibrosis: Incidence, Survival and Impact of the CFTR Gene Discovery

Significant advances in the management of cystic fibrosis (CF) in recentdecades have dramatically changed the epidemiology and prognosis of this serious disease, which is no longer an exclusively pediatric disease. This paper aims to review the changes in the incidence and survival of CF and to assess the impact of the discovery of the responsible gene (the CFTR gene) on these changes. The incidence of CF appears to be decreasing in most countries andpatient survival, which can be monitored by various indicators, has improved substantially, with an estimated median age of survivalof approximately50 years today. Cloning of the CFTR gene 30 years ago and efforts to identify its many mutations have greatly improved the management of CF. Implementation of genetic screening policies hasenabled earlier diagnosis (via newborn screening), in addition to prevention within families or in the general population in some areas (via prenatal diagnosis, family testing or population carrier screening). In the past decade, in-depth knowledge of the molecular bases of CF has also enabled the emergenceof CFTR modulator therapies which have led to major clinical advances in the treatment of CF. All of these phenomena have contributed to changing the face of CF. The advent of targeted therapies has paved the way for precision medicine and is expected to further improve survival in the coming years.

Newborn Screening for CF across the Globe-Where Is It Worthwhile?

Newborn screening (NBS) for cystic fibrosis (CF) has been performed in many countries for as long as four decades and has transformed the routine method for diagnosing this genetic disease and improved the quality and quantity of life for people with this potentially fatal disorder. Each region has typically undertaken CF NBS after analysis of the advantages, costs, and challenges, particularly regarding the relationship of benefits to risks. The very fact that all regions that began screening for CF have continued their programs implies that public health and clinical leaders consider early diagnosis through screening to be worthwhile. Currently, many regions where CF NBS has not yet been introduced are considering options and in some situations negotiating with healthcare authorities as policy and economic factors are being debated. To consider the assigned question (where is it worthwhile?), we have completed a worldwide analysis of data and factors that should be considered when CF NBS is being contemplated. This article describes the lessons learned from the journey toward universal screening wherever CF is prevalent and an analytical framework for application in those undecided regions. In fact, the lessons learned provide insights about what is necessary to make CF NBS worthwhile.

Newborn Screening: Current Status in Alberta, Canada

Newborn screening (NBS) in Alberta is delivered by a number of government and health service entities who work together to provide newborn screening to infants born in Alberta, the Northwest Territories, and the Kitikmeot region of the Nunavut territory. The Alberta panel screens for 21 disorders (16 metabolic, two endocrine, cystic fibrosis, severe combined immunodeficiency, and sickle cell disease). NBS is a standard of care, but is not mandatory. NBS performance is monitored by the Alberta Newborn Metabolic Screening (NMS) Program and NMS Laboratory, who strive for continuous quality improvement. Performance analysis found that over 99% of registered infants in Alberta received a newborn screen and over 98% of these infants received a screen result within 10 days of age.

The benefits of newborn screening for cystic fibrosis: The Canadian experience

BACKGROUND

The impact of newborn screening (NBS) for cystic fibrosis (CF) on early indicators of long-term health was evaluated in the context of government-sponsored healthcare and access to current therapies.

METHODS

Using data from the Canadian CF Registry between 2008 and 2013, we compared the rates of respiratory infections and markers of nutritional status in those diagnosed through NBS to those who were diagnosed clinically within the same time period using Mann-Whitney and Fischer's exact test as appropriate.

RESULTS

The study included 303 subjects, 201 in the NBS group and 102 in the non-NBS group. NBS patients were diagnosed earlier and had their first clinic visit at a younger age. Pancreatic insufficiency was less common in NBS patients. The incidence of Pseudomonas aeruginosa and Staphylococcus aureus were lower in NBS patients. After adjusting for age at clinic visit, gender, pancreatic status, and Pseudomonas aeruginosa infection status, mean z-scores for weight-for-age and height-for-age were higher in NBS patients, with no differences in BMI-for-age.

CONCLUSIONS

NBS programs for CF lead to improved long-term health outcomes for the CF population.

Expectations and values about expanded newborn screening: a public engagement study

OBJECTIVES

Newborn bloodspot screening (NBS) panels have expanded to include conditions for which treatment effects are less certain, creating debate about population-based screening criteria. We investigated Canadian public expectations and values regarding the types of conditions that should be included in NBS and whether parents should provide consent.

METHODS

Eight focus groups (FG; n = 60) included education, deliberative discussion and pre-/post-questionnaires. Data were analysed quantitatively and qualitatively.

RESULTS

Quantitatively, the majority supported NBS for serious disorders for which treatment is not available (95-98, 82%). A majority endorsed screening without explicit consent (77-88%) for treatable disorders, but 62% supported unpressured choice for screening for untreatable disorders. Qualitatively, participants valued treatment-related benefits for infants and informational benefits for families. Concern for anxiety, stigma and unwanted knowledge depended upon disease context and strength of countervailing benefits.

CONCLUSIONS

Anticipated benefits of expanded infant screening were prioritized over harms, with information provision perceived as a mechanism for mitigating harms and enabling choice. However, we urge caution around the potential for public enthusiasm to foster unlimited uptake of infant screening technologies.

A new era in the treatment of cystic fibrosis: correction of the underlying CFTR defect

Cystic fibrosis is caused by dysfunction or deficiency of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, an epithelial chloride channel that has a key role in maintaining homoeostasis of the airway surface liquid layer in the lungs. More than 1900 CFTR mutations that might result in a disease phenotype have been identified; these can be grouped into classes on the basis of their effect on CFTR protein production, trafficking, function, and stability. In the past 2 years, landmark clinical trials have shown that correction of CFTR function leads to substantial clinical benefit for individuals with cystic fibrosis. These findings are ushering in a new era of cystic fibrosis treatments designed to correct the underlying CFTR defect caused by different mutation classes. With analysis of continuing trials and available patient registries, here we assess mutation types and the number and geographical distribution of patients who are likely to benefit from CFTR-correcting treatment.

Newborn screening for cystic fibrosis

PURPOSE OF REVIEW

Newborn screening for cystic fibrosis (CF) is now universal in the US and many other countries. The rapid expansion of screening has resulted in numerous publications identifying new challenges for healthcare providers. This review provides an overview of these publications and includes ideas on managing these challenges.

RECENT FINDINGS

Most CF newborn screening algorithms involve DNA mutation analysis. As screening has expanded, new challenges have been identified related to carrier detection and inconclusive diagnoses. Early descriptions of infants with CF-related metabolic syndrome (CRMS) indicate that the natural history of this condition cannot be predicted. Early identification has also provided an opportunity to better understand the pathophysiology of CF. However, few studies have been conducted in infants with CF to determine optimal therapy and recommendations are largely anecdotal.

SUMMARY

Newborn screening provides an opportunity to identify and begin treatment early in individuals with CF. Whereas a single, optimal approach to screening does not exist, all programs can benefit from new findings regarding sweat testing, carrier detection, early pathophysiology, and clinical outcomes.

Newborn screening: ethical, legal, and social implications

Newborn dried blood spot screening (NBS) is a core public health service and is the largest application of genetic testing in the United States. NBS is conducted by state public health departments to identify infants with certain genetic, metabolic, and endocrine disorders. Screening is performed in the first few days of life through blood testing. Several drops of blood are taken from the baby's heel and placed on a filter paper card. The dried blood, on the filter cards, is sent from the newborn nursery to the state health department laboratory, or a commercial partner, where the blood is analyzed. Scientific and technological advances have lead to a significant expansion in the number of tests-from an average of 6 to more than 50--and there is a national trend to further expand the NBS program. This rapid expansion has created significant ethical, legal, and social challenges for the health care system and opportunity for scholarly inquiry to address these issues. The purpose of this chapter is to provide an overview of the NBS programs and to provide an in-depth examination of two significant concerns raised from expanded newborn screening, specifically false-positives and lack of information for parents. Implications for nursing research in managing these ethical dilemmas are discussed.