Outcomes of infants with indeterminate diagnosis detected by cystic fibrosis newborn screening

New York cystic fibrosis consortium newborn screening quality improvement: Development and implementation of a statewide consensus recommendations for management of infants with CFTR-related metabolic syndrome

BACKGROUND

New York (NY) State implemented a new cystic fibrosis (CF) newborn screen (NBS) algorithm in December 2017 with improvement in positive predictive value and unanticipated increased identification of infants with cystic fibrosis transmembrane conductance regulator (CFTR)-related metabolic syndrome (CRMS). Repeat sweat testing is recommended in infants with CRMS. During the COVID-19 pandemic infants with CRMS were lost to follow up. With this quality improvement (QI) initiative, we aimed to perform repeat sweat testing in 25% of infants lost to follow up. We also describe consensus recommendations for CRMS from the NY CF NBS Consortium.

METHODS

Our QI team identified the primary drivers contributing to absent follow up, outreached to families, and created a questionnaire to evaluate parental understanding of CRMS using QI-based strategies.

RESULTS

Of 350 infants diagnosed with CRMS during the study period, 179 (51.1%) infants were lost to follow up. A total of 31 (17.3%) were scheduled for repeat sweat tests and followed up at CF Centers. Families reported high satisfaction with the CRMS knowledge questionnaire.

CONCLUSIONS

With this QI-based approach, we effectively recaptured infants with CRMS previously lost to follow up during the COVID-19 pandemic. Ongoing concerns about infection risk and lack of understanding on the part of families and pediatricians likely contributed to patients with CRMS lost to follow up. Consensus recommendations for CRMS include annual visits with repeat sweat testing until 2-6 years of age and education for adolescents about clinical and reproductive implications of CRMS.

Biochemical and genetic tools to predict the progression to Cystic Fibrosis in CRMS/CFSPID subjects: A systematic review

OBJECTIVES

Aim of this study was to identify risk factors for a progression to cystic fibrosis (CF) in individuals detected as CF Screening Positive, Inconclusive Diagnosis (CFSPID).

METHODS

This is a systematic review through literature databases (2015-2023). Blood immunoreactive trypsinogen (b-IRT) values, CFTR genotype, sweat chloride (SC) values, isolation of Pseudomonas aeruginosa (Pa) from respiratory samples, Lung Clearance Index (LCI) values in CFSPIDs who converted to CF (CFSPID > CF) and age at CF transition were assessed.

RESULTS

Percentage of CFSPID > CF varies from 5.3 % to 44 %. Presence of one CF-causing CFTR variant in trans with a variant with variable clinical consequences (VVCC), an initial SC ≥ 40 mmol/L, an increase of SC > 2.5 mmol/L/year and recurrent isolation of pseudomonas aeruginosa (Pa) from airway samples could allow identification of subjects at risk of progression to CF.

CONCLUSIONS

CFSPIDs with CF causing variant/VVCC genotype and first SC in the higher borderline range may require more frequent and prolonged clinical follow-up.

Literary evidence of the impact of nonbiological risk factors on CRMS/CFSPID: A scoping review

Newborn screening for cystic fibrosis (CF) occasionally results in an inconclusive diagnosis of this disease, and these individuals are designated as CFTR-related metabolic syndrome (CRMS) in the United States, and CF Screen Positive Inconclusive Diagnosis (CFSPID) in other countries. Some of these asymptomatic individuals will progress to symptomatic disease, but risk factors associated with disease progression are not well understood. This scoping review was conducted to comprehensively map nonbiological risk factors in the CRMS/CFSPID literature and to identify understudied topics. Six electronic databases were systematically searched, resulting in 2951 studies. Forty nine eligible works were identified as including information on nonbiological risk factors related to CRMS/CFPSID. Eligible studies were published from 2002 to 2024, most prevalently in the United States (36.7%), and as quantitative data (81.6%). Of the 49 eligible works, 23 articles contributed only intellectual conjecture, while 26 articles contained original data, which underwent full-text qualitative content analysis. Key themes identified in descending order of content coverage included Psychological Impact, Management Care, Newborn Screening and Diagnostics, Communicating Diagnosis, and Lifestyle and External Exposures. This scoping review identified that while nonbiological risk factors are being studied in the CRMS/CFSPID literature, there was nearly equal distribution of works gathering original data to those citing previously published information. These findings indicate a critical need for original data collection on these risk factors, particularly on understudied topics identified herein.

Pancreatic enzyme prescription following ivacaftor licensing: A retrospective analysis of the US and UK cystic fibrosis registries

BACKGROUND

Relieving gastrointestinal symptoms is a research priority in cystic fibrosis. Emerging evidence highlights effects of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on gastrointestinal function, including pancreatic sufficiency. This study explores ivacaftor licensing and treatment on recorded pancreatic enzyme replacement therapy (PERT) prescription in the US and UK CF registries.

METHODS

Retrospective longitudinal registry study of recorded pancreatic PERT use between 2008 and 2017. Interrupted time series analysis in propensity-matched cohorts estimated annual change and step change according to ivacaftor eligibility before and after licensing year, 2012. Generalised estimating equations assessed adjusted risk of PERT use in individuals treated with ivacaftor after 2012 compared to untreated individuals.

RESULTS

In the US CF registry, the difference in annual change in prevalence of PERT use post-2012 between eligible cases and ineligible controls was -5.0 per 1000 people/year (95 %CI -7.6; -2.3, p = 0.001). The step change and annual change in prevalence of PERT use in eligible cases was not significantly different to controls in the UK CF registry. Relative to the relationship in 2013, ivacaftor treatment in the US CF registry was associated with a lower adjusted risk ratio of PERT use compared to untreated individuals by 2016 (0.97, 95 %CI 0.96; 0.99), which was not observed in the UK CF registry.

CONCLUSIONS

Licensing of ivacaftor was followed by a lower prevalence of PERT use in the eligible US population compared to pre-licensing period, as well as lower risk of PERT use in those who received treatment. Inconsistencies in US and UK CF registries were observed.

Update on advances in cystic fibrosis towards a cure and implications for primary care clinicians

During the past quarter century, the diagnosis and treatment of cystic fibrosis (CF) have been transformed by molecular sciences that initiated a new era with discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The knowledge gained from that breakthrough has had dramatic clinical impact. Although once a diagnostic dilemma with long delays, preventable deaths, and irreversible pathology, CF can now be routinely diagnosed shortly after birth through newborn screening programs. This strategy of pre-symptomatic identification has eliminated the common diagnostic "odyssey" that was a failure of the healthcare delivery system causing psychologically traumatic experiences for parents. Therapeutic advances of many kinds have culminated in CFTR modulator treatment that can reduce the effects of or even correct the molecular defect in the chloride channel -the basic cause of CF. This astonishing advance has transformed CF care as described fully herein. Despite this impressive progress, there are challenges and controversies in the delivery of care. Issues include how best to achieve high sensitivity newborn screening with acceptable specificity; what course of action is appropriate for children who are identified through the unavoidable incidental findings of screening tests (CFSPID/CRMS cases and heterozygote carriers); how best to ensure genetic counseling; when to initiate the very expensive but life-saving CFTR modulator drugs; how to identify new CFTR modulator drugs for patients with non-responsive CFTR variants; how to adjust other therapeutic modalities; and how to best partner with primary care clinicians. Progress always brings new challenges, and this has been evident worldwide for CF. Consequently, this article summarizes the major advances of recent years along with controversies and describes their implications with an international perspective.

Clinical outcomes at 9-10 years of age in children born with cystic fibrosis transmembrane conductance regulator related metabolic syndrome

BACKGROUND AND OBJECTIVES

There are limited data on cystic fibrosis (CF) transmembrane conductance regulator-related metabolic syndrome (CRMS) outcomes beyond infancy. The goal of this study was to analyze outcomes of infants with CRMS up to the age of 9-10 years using the CF Foundation Patient Registry (CFFPR).

METHODS

We analyzed data from the CFFPR for individuals with CF and CRMS born between 2010 and 2020. We classified all patients based on the clinical diagnosis reported by the CF care center and the diagnosis using CFF guideline definitions for CF and CRMS, classifying children into groups based on agreement between clinical report and guideline criteria. Descriptive statistics for the cohort were calculated for demographics, nutritional outcomes, and microbiology for the first year of life and lung function and growth outcomes were summarized for ages 6-10 years.

RESULTS

From 2010 to 2020, there were 8765 children with diagnosis of CF or CRMS entered into the CFFPR with sufficient diagnostic data for classification, of which 7591 children had a clinical diagnosis of CF and 1174 had a clinical diagnosis of CRMS. CRMS patients exhibited normal nutritional indices and pulmonary function up to age 9-10 years. The presence of respiratory bacteria associated with CF, such as Pseudomonas aeruginosa from CRMS patients ranged from 2.1% to 9.1% after the first year of life.

CONCLUSIONS

Children with CRMS demonstrate normal pulmonary and nutritional outcomes into school age. However, a small percentage of children continue to culture CF-associated respiratory pathogens after infancy.

Cystic Fibrosis Foundation Evidence-Based Guideline for the Management of CRMS/CFSPID

A multidisciplinary committee developed evidence-based guidelines for the management of cystic fibrosis transmembrane conductance regulator-related metabolic syndrome/cystic fibrosis screen-positive, inconclusive diagnosis (CRMS/CFSPID). A total of 24 patient, intervention, comparison, and outcome questions were generated based on surveys sent to people with CRMS/CFSPID and clinicians caring for these individuals, previous recommendations, and expert committee input. Four a priori working groups (genetic testing, monitoring, treatment, and psychosocial/communication issues) were used to provide structure to the committee. A systematic review of the evidence was conducted, and found numerous case series and cohort studies, but no randomized clinical trials. A total of 30 recommendations were graded using the US Preventive Services Task Force methodology. Recommendations that received ≥80% consensus among the entire committee were approved. The resulting recommendations were of moderate to low certainty for the majority of the statements because of the low quality of the evidence. Highlights of the recommendations include thorough evaluation with genetic sequencing, deletion/duplication analysis if <2 disease-causing variants were noted in newborn screening; repeat sweat testing until at least age 8 but limiting further laboratory testing, including microbiology, radiology, and pulmonary function testing; minimal use of medications, which when suggested, should lead to shared decision-making with families; and providing communication with emphasis on social determinants of health and shared decision-making to minimize barriers which may affect processing and understanding of this complex designation. Future research will be needed regarding medication use, antibiotic therapy, and the use of chest imaging for monitoring the development of lung disease.

Single-centre prospective evaluation of the first 5 years of cystic fibrosis newborn screening in Germany

Background

In 2016, nationwide cystic fibrosis newborn screening (CFNS) was newly implemented in Germany, using an immunoreactive trypsin/pancreatitis-associated protein/DNA screening algorithm that differs from most other nationwide screening programmes.

Methods

We analysed real-life feasibility of the confirmation process with respect to our pre-specified procedural objectives. These included overall accuracy through false-negative and false-positive results, effectiveness of the Bavarian tracking system, and accuracy of Macroduct and Nanoduct sweat conductivity compared with quantitative chloride determination. All consecutive CFNS-positive newborns assigned to our CF centre and born between 1 September 2016 and 31 August 2021 (n=162) were included.

Results

The German CFNS was feasible at our CF centre as all procedural objectives were met. The positive predictive value (PPV) of positive CFNS was low (0.23) and two initially negatively screened children were later diagnosed with CF. The tracking system was highly efficient with a 100% tracking rate. The Macroduct and Nanoduct systems had comparable success rates (93.2% versus 95.9%). Importantly, conductivity via Macroduct was more accurate than via Nanoduct (zero and four false-positive newborns, respectively).

Conclusions

CF confirmation diagnostics of neonates in a certified regional CF centre was well managed in daily routine. The PPV of the German CFNS needs to be improved, e.g. by extending the DNA analysis within the screening algorithm and by increasing the number of variants tested. The Bavarian tracking system can serve as a successful model for other tracking systems. We preferred the Macroduct system because of its more accurate sweat conductivity readings.

Children with cystic fibrosis are still receiving inconclusive diagnosis despite undergoing newborn screening

AIM

We aimed to familiarise clinicians with the terms cystic fibrosis transmembrane conductance regulator related metabolic syndrome (CRMS) and cystic fibrosis screen positive inconclusive diagnosis (CFSPID). We also sought to highlight the monitoring and outcomes of children that match these designations.

METHODS

A literature review was performed by searching PubMed from its inception until 30 November 2022. All relevant articles were included in this narrative review.

RESULTS

Despite the implementation of newborn screening programmes for cystic fibrosis (CF), the diagnosis remains uncertain in some newborn infants with elevated immunoreactive trypsinogen. In 2016, a unified definition for CRMS/CFSPID was established to categorise these children. While many of them remain healthy, a portion of these children may develop CF. As a result, it is crucial to monitor them regularly.

CONCLUSION

CRMS/CFSPID is a designation and not a diagnosis. Longer longitudinal studies are needed to shed light on the most appropriate follow-up of these children. Paediatricians need to be knowledgeable about this condition in order to administer proper care, and children should be in contact with their local CF centre.

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.

High rates of anxiety detected in mothers of children with inconclusive cystic fibrosis screening results

OBJECTIVE

The purpose was to assess postpartum depression, anxiety, and depression in mothers of children with an inconclusive diagnosis after a positive cystic fibrosis (CF) newborn screening (NBS), known as cystic fibrosis transmembrane conductance regulator (CFTR)-related metabolic syndrome (CRMS) or CF screen positive, inconclusive diagnosis (CFSPID). There is limited information on the prognosis and on the impact of this designation on maternal mental health.

METHODS

Mothers of children with CRMS/CFSPID and CF identified by NBS were recruited from two centers in California. Maternal mental health was assessed using measures of depression, anxiety, and a scripted interview. Descriptive statistics and multivariate logistic regression were applied for data reporting.

RESULTS

A total of 109 mothers were recruited: CF: 51, CRMS/CFSPID: 58. Mothers from both groups showed higher rates of depression and anxiety symptoms than women in the general population. CRMS/CFSPID and CF mothers had no significant difference on their self-reported symptoms of anxiety and depression after adjusting for potential confounders. Mothers equally reported that their child's diagnosis had a negative impact, and that genetic counseling had a positive impact on their emotional health.

CONCLUSIONS

CF and CRMS/CFSPID diagnoses impact maternal mental health similarly. Uncertain prognosis of CRMS/CFSPID likely contributed to the negative mental health impact. Providers should consider conducting mental health screening for every mother of a child with CRMS/CFSPID, in addition to the recommended mental health screening for mothers of children with CF. Genetic counseling has potential to mitigate emotional stress on these families.

Gradual increase in sweat chloride concentration is associated with a higher risk of CRMS/CFSPID to CF reclassification

OBJECTIVES

Universal implementation of cystic fibrosis (CF) newborn screening (NBS) has led to the diagnostic dilemma of infants with CF screen-positive, inconclusive diagnosis (CFSPID), with limited guidance regarding prognosis and standardized care. Rates of reclassification from CFSPID to CF vary and risk factors for reclassification are not well established. We investigated whether clinical characteristics are associated with the risk of reclassification from CFSPID to a CF diagnosis.

METHODS

Children with a positive CF NBS were recruited from two sites in California. Retrospective, longitudinal, and cross-sectional data were collected. A subset of subjects had nasal epithelial cells collected for CF transmembrane conductance regulator (CFTR) functional assessment. Multivariate logistic regression was used to assess the risk of reclassification.

RESULTS

A total of 112 children completed the study (CF = 53, CFSPID = 59). Phenotypic characteristics between groups showed differences in pancreatic insufficiency prevalence, immunoreactive trypsinogen (IRT) levels, and Pseudomonas aeruginosa (PSA) colonization. Spirometry measures were not different between groups. Nasal epithelial cells from 10 subjects showed 7%-30% of wild-type (WT)-CFTR (wtCFTR) function in those who reclassified and 27%-67% of wtCFTR function in those who retained the CFSPID designation. Modeling revealed that increasing sweat chloride concentration (sw[Cl^- ]) and PSA colonization were independent risk factors for reclassification to CF.

CONCLUSION

Increasing sw[Cl^- ] and a history of PSA colonization are associated with the risk of reclassification from CFSPID to CF in a population with high IRT and two CFTR variants. A close follow-up to monitor phenotypic changes remains critical in this population. The role of CFTR functional assays in this population requires further exploration.

Cystic Fibrosis Screen Positive, Inconclusive Diagnosis Genotypes in People with Cystic Fibrosis from the U.S. Patient Registry

Rationale: Variants within the cystic fibrosis (CF) transmembrane conductance regulator gene, CFTR, that are of unknown significance or are categorized as non-CF causing may be observed in persons with CF. These variants are frequently detected in children with inconclusive newborn screen results and, in some cases, may be associated with a benign presentation in early childhood that progresses to a CF phenotype later in life. Objectives: To analyze data from individuals enrolled in the U.S. Cystic Fibrosis Foundation Patient Registry who have received a diagnosis of CF and who have variants found in a population of children with a CF screen positive, inconclusive diagnosis (CFSPID). Methods: This retrospective review analyzed registry data from individuals with a diagnosis of CF who also harbor one or more variants of interest because of their frequency within a CFSPID population and/or their interpretation as non-CF causing. Three groups were defined by the number of CF-causing variants identified (CF-Cx2, CF-Cx1, and CF-Cx0), which were reported in addition to the variant(s) of interest. Multivariate quantile regression modeling of the outcome for forced expiratory volume in 1 second (FEV1) generated a disease severity score for each person determined by six selected variables. Median scores were calculated for the three groups. Results: Patients carrying one CF-causing variant and at least one variant of interest (CF-Cx1) had higher median disease severity scores compared with those carrying CF-Cx2, suggesting a milder phenotype (P < 0.05). However, there was no statistically significant difference in scores between CF-Cx2 and the two other groups combined (CF-Cx1 and CF-Cx0; P = 0.33). Analysis revealed that the CF-Cx1 and CF-Cx0 groups, when compared with the CF-Cx2 group, had later median diagnoses (8 years vs. newborn; P < 0.0001), lower median sweat chloride (48 mmol/L vs. 94.5 mmol/L; P < 0.0001), lower prevalence of pancreatic insufficiency (29% vs. 78%; P < 0.0001), and higher median FEV1% predicted (95% vs. 87%; P = 0.0002). Conclusions: Individuals with CF who have specific variants frequently identified in children with CFSPID have a similar range of disease severity scores compared with those who have two CF-causing variants, but a milder phenotype overall. Variants that should be given careful scrutiny because of their high prevalence are G576A+R668C, T854T, R75Q, F1052V, R1070W, R31C, and L967S.

Outcomes of children with cystic fibrosis screen positive, inconclusive diagnosis/CFTR related metabolic syndrome

Background

Some infants undergoing newborn screening (NBS) tests have inconclusive sweat chloride test (SCT) results that lead to the designation of Cystic Fibrosis Screen Positive, Inconclusive Diagnosis/CFTR-related metabolic syndrome (CFSPID/CRMS). Some proportion of them transition to a CF diagnosis, but no predictive markers can stratify which are at risk for this transition. We report single-center outcomes of children with CRMS.

Methods

We retrospectively identified all infants born in Alabama from 2008 through 2020 referred to our CF Center with an elevated immunoreactive trypsinogen level (IRT) associated with a cystic fibrosis transmembrane conductance regulator (CFTR) mutation (IRT+/DNA+) who had at least one SCT result documented. Infants were classified per established guidelines as Carrier, CRMS, or CF based on the IRT+/DNA+ and SCT results. The electronic health record was reviewed for follow-up visits until the children received a definitive diagnosis (to carrier or CF) according to current diagnostic guidelines for CF, or through the end of the 2020 year.

Results

Of the 1,346 infants with IRT+ and at least 1 CFTR mutation identified (IRT+/DNA+), 63 (4.7%) were designated as CRMS. Of these infants, 12 (19.1%) transitioned to Carrier status (CRMS-Carrier), 40 (63.5%) of them remained CRMS status (CRMS-Persistent) and 11 (17.5%) of them transitioned to a diagnosis of CF (CRMS-CF). Of the 11 children in the CRMS-CF group, 4 (36%) had an initial SCT 30-39 mmol/L, 4 (36%) had an initial SCT 40-49 mmol/L and 3 (27%) had an initial SCT 50-59 mmol/L. These children also had higher initial sweat tests and greater yearly increases in sweat chloride values than others with CRMS. We found that in comparison to children in the CRMS-P group, a greater proportion of children in the CRMS-CF group cultured bacteria like methicillin-resistant Staphylococcus aureus, Stenotrophomonas maltophilia, and Pseudomonas aeruginosa, had smaller weight-for-height percentiles and remained smaller over time despite slightly greater growth.

Conclusion

Infants with an inconclusive diagnosis of CF should continue to receive annual care and management given their potential risk of transition to CF. Further research is needed to assess whether certain phenotypic patterns, clinical symptoms, diagnostic tests or biomarkers could better stratify these children.

Different management approaches and outcome for infants with an inconclusive diagnosis following newborn screening for cystic fibrosis (CRMS/CFSPID) and Pseudomonas aeruginosa isolation

INTRODUCTION

Evidence is currently lacking to guide the management of cystic fibrosis (CF) transmembrane conductance regulator-related metabolic syndrome CF screen-positive inconclusive diagnosis (CRMS/CFSPID) with Pseudomonas aeruginosa (Pa)-positive respiratory culture. This study assessed the clinical data, management, and outcomes of an Italian cohort of CRMS/CFSPID infants with Pa isolated from their airways.

METHODS

Data of Pa-positive CRMS/CFSPID infants born between January 2011 and August 2018 and followed at five CF Italian centres were retrospectively extracted. Further data were collected until June 2021 to assess outcomes, prevalence of subjects treated with antimicrobials, and treatment type and duration.

RESULTS

Forty-three asymptomatic CRMS/CFSPID patients (median age on 30 June 2021, 82 months; interquartile range [IQR], 63-98 months) with at least one positive airway culture for non-mucoid Pa (median age at first isolation, 18.7 months; IQR, 7-25 months) were enrolled. Of them, 24 (55.8%) underwent anti-Pa therapy. Pa clearance occurred in 22 (91.6%) of 24 patients versus spontaneous clearance in 16 of 19 (84.2%) untreated patients (chi-square, 0.5737; p = 0.44878). After a median follow-up of 6.2 years (IQR, 3.0-9.9), 7 (16.3%) were diagnosed with CF after a pathological sweat test (median age, 43 months; IQR, 28-77 months), 3 (7%) developed recurrent pancreatitis or isolated bronchiectasis consistent with CFTR-related disorder, and the CRMS/CFSPID classification remained in 33 (76.7%).

CONCLUSIONS

Pa detection frequently occurs in asymptomatic infants with CRMS/CFSPID but tends to clear spontaneously. More studies are needed to determine if Pa isolation can predict evolution.

Nutritional status and lung function in children with pancreatic-sufficient cystic fibrosis

BACKGROUND

There is a strong association between nutrition and long-term FEV1 in cystic fibrosis (CF), but studies have been driven by data from subjects with pancreatic insufficiency (PI-CF). We thus evaluated the association between body mass index (BMI) and FEV1 percent-predicted (FEV1pp) in children with pancreatic sufficiency (PS-CF) and contrasted it with the association in PI-CF.

METHODS

We utilized data from the CF Foundation Patient Registry. The cohort included children born 1995-2010, diagnosed <2 years of age, and who had annualized data on BMI percentile and FEV1pp at ages 6-16 years. Pancreatic status was defined based on pancreatic enzyme replacement therapy. The association between BMI and FEV1 was evaluated using linear and mixed-effects longitudinal regression.

RESULTS

There were 424 children with PS-CF and 7,849 with PI-CF. The association between BMI and FEV1 differed significantly by pancreatic status: each 10-pct higher BMI was associated with 2% [95%CI = 1.9-2.1] higher FEV1pp in PI-CF, compared to just 0.9% [0.5-1.3] in PS-CF (PINTERACTION < 0.001). Within the at-risk nutritional category (BMI <25pct), each 10-pct higher BMI was associated with 5% higher FEV1pp in PI-CF, but no significant increase in PS-CF. Moreover, in PS-CF, overweight/obesity (BMI ≥85pct) was associated with decreasing FEV1pp. In addition, FEV1pp decline through age 20 years in youth with PS-CF was modest (-0.6% per year) and independent of BMI (BMI*age PINTERACTION = 0.37).

CONCLUSIONS

In children with PS-CF, BMI remains an important determinant of lung function. However, it may be less critical to attain a BMI >50th percentile; and BMI ≥85th percentile may be detrimental.

Reclassifying inconclusive diagnosis after newborn screening for cystic fibrosis. Moving forward

BACKGROUND

Newborn screening for Cystic Fibrosis (CF) is associated with situations where the diagnosis of CF or CFTR related disorders (CFTR-RD) cannot be clearly ruled out.

MATERIALS/PATIENTS AND METHODS

We report a case series of 23 children with unconclusive diagnosis after newborn screening for CF and a mean follow-up of 7.7 years (4-13). Comprehensive investigations including whole CFTR gene sequencing, in vivo intestinal current measurement (ICM), nasal potential difference (NPD), and in vitro functional studies of variants of unknown significance, helped to reclassify the patients.

RESULTS

Extensive genetic testing identified, in trans with a CF causing mutation, variants with varying clinical consequences and 3 variants of unknown significance (VUS). Eighteen deep intronic variants were identified by deep resequencing of the whole CFTR gene in 13 patients and were finally considered as non-pathogenic. All patients had normal CFTR dependent chloride transport in ICM. NPD differentiated 3 different profiles: CF-like tracings qualifying the patients as CF, such as F508del/D1152H patients; normal responses, suggesting an extremely low likelihood of developing a CFTR-RD such as F508del/TG11T5 patients; partial CFTR dysfunction above 20% of the normal, highlighting a remaining risk of developing CFTR-RD such as F508del/F1052V patients. The 3 VUS were reclassified as variant with defective maturation (D537N), defective expression (T582I) or with no clinical consequence (M952T).

CONCLUSION

This study demonstrates the usefulness of combining genetic and functional investigations to assess the possibility of evolving to CF or CFTR-RD in babies with inconclusive diagnosis at neonatal screening.

Outcomes of infants born during the first 9 years of CF newborn screening in the United States: A retrospective Cystic Fibrosis Foundation Patient Registry cohort study

INTRODUCTION

Newborn screening (NBS) for cystic fibrosis (CF) was implemented in all US states and DC by 2010. This hypothesis-generating study was designed to form the basis of additional analyses and to plan quality improvement initiatives. The aims were to describe the outcomes of infants with CF born during the first 9 years of universal NBS.

METHODS

We included participants in the CF Foundation Patient Registry born 2010-2018 with age of recorded CF diagnosis 0-365 days old. We compared the age of center-reported diagnosis, age at first CF event (defined as earliest sweat test, clinic visit, or hospitalization), demographics, and outcomes between three cohorts born between 2010-2012, 2013-2015, and 2016-2018.

RESULTS

In 6354 infants, the median age at first CF event decreased from the first to the third cohort. Weight-for-age (WFA) was < 10th percentile in about 40% of infants at the first CF Center visit. Median WFA z-score at 1-2 years was more than 0 but height-for-age (HFA) z-score was less than 0 through age 5-6 years. The second cohort had a higher HFA z-score than the first cohort at age 5-6 years. Pseudomonas aeruginosa infection was less common in later cohorts. About 1/3 of infants were hospitalized in the first year of life with no changes over time.

CONCLUSION

Over 9 years of CF NBS, median age at first CF event decreased. CF NBS had positive health impacts, but early life nutritional deficits and a high rate of infant hospitalizations persist.

When CFSPID becomes CF

There has been a growing number of infants identified as CRMS/CFSPID in countries applying genetic testing as part of cystic fibrosis (CF) newborn screening. Currently there are neither standardized protocols for follow up beyond infancy, nor established predictors to stratify this population as high or low risk of reclassification to CF or CFTR-related disorder. We report a series of 10 children who reclassified, including eight carrying CFTR variants of varying clinical consequence and seven with initial sweat chloride measurements <30 mmol/L. The overall increase in sweat chloride concentration was 5.8 mmol/L/year. Pseudomonas aeruginosa was isolated from respiratory cultures in five subjects, and reclassification was aided by human nasal epithelial cultures in two cases. In this center's experience, 6% of all CRMS/CFSPID referrals reclassified to CF over a 12-year period. The rate of sweat chloride increase, genotype, and CFTR functional assay can potentially be used as prognostic tools in the CRMS/CFSPID population.

Outcomes of repeat sweat testing in cystic fibrosis newborn screen positive infants

BACKGROUND

Infants with a positive cystic fibrosis (CF) newborn screen, only one identified CFTR mutation (NBS+/1 mut), and an initial intermediate sweat chloride (30-59 mmol/L) should have repeat sweat chloride testing (SCT). However, the outcome of repeat SCT and the relationship between initial sweat Cl and subsequent CF diagnosis have not been reported.

OBJECTIVE

The objective of this study was to analyze the outcomes of repeat SCT and subsequent CF diagnosis in NBS+/1 mut infants based on their initial sweat chloride concentration.

METHODS

We retrospectively identified all infants born in Indiana from 2007 to 2017 with NBS+/1 mut and initial SCT in the intermediate range. For each infant, we recorded the initial and repeat SCT results and/or a final CF diagnosis.

RESULTS

From 2007 through 2017 there were 2822 NBS+/1 mut infants of which 2613 (82%) had at least one SCT result. No infants with an initial SCT of 30-39 mmol/L were subsequently diagnosed with CF. Of the 31 infants with an initial SCT of 40-49 mmol/L, only 1 was subsequently diagnosed with CF. In contrast, 61% of those with SCTs of 50-59 mmol/L were later diagnosed with CF.

CONCLUSION

These results suggest that infants with a positive NBS for CF and one CFTR mutationwhose initial sweat chloride concentration is 50-59 mmol/L need to be monitored more closely forCF with strong consideration for earlier repeat SCTs and immediate genotyping.

[Newborn screening for cystic fibrosis in France]

Neonatal screening for cystic fibrosis has optimised the prognosis for patients allowing very early multidisciplinary care. Over the past 20 years, screening programmes have undergone major international expansion. The performances of the French neonatal cystic fibrosis screening programme, established in 2002, has met European guideline standards, with positive predictive value of 0.31 (against a minimum of 0.30) and sensitivity value of 0.95 (against a minimum of 0.95). It is also important to highlight the very high percentage of sweat tests performed (95.5%), of mutations identified (96.6%), the 9:1 ratio of cystic fibrosis cases to cases of inconclusive diagnosis achieved and the effectiveness of the strategy implemented for the detection of false negative cases. A new organisation for cystic fibrosis neonatal screening has now been established in France. It is vital that effectiveness is maintained throughout the process, from newborn maternity care to diagnosis in cystic fibrosis care centres, and that further knowledge is gained through exhaustive data collection and validation.

CRMS/CFSPID Subjects Carrying D1152H CFTR Variant: Can the Second Variant Be a Predictor of Disease Development?

Background: There are no predictive factors of evolution of cystic fibrosis (CF) screen positive inconclusive diagnosis subjects (CFSPIDs). Aim: to define the role of the second CFTR variant as a predictive factor of disease evolution in CFSPIDs carrying the D1152H variant. Methods: We retrospectively evaluated clinical characteristics and outcome of CFSPIDs carrying the D1152H variant followed at five Italian CF centers. CFSPIDs were divided in two groups: Group A: compound heterozygous for D1152H and a CF-causing variant; Group B: compound heterozygous for D1152H and a: (i) non CF-causing variant, (ii) variant with varying clinical consequences, or (iii) variant with unknown significance. The variants were classified according to CFTR2 mutation database. Results: We enrolled 43 CFSPIDs with at least one D1152H variant: 28 (65.1%) were classified in the group A, and 15 (34.9%) in the Group B. CFSPIDs of group A had the first IRT significantly higher compared to those of group B (p < 0.05) and had a more severe clinical outcome during the follow-up. At the end of the study period, after a mean follow-up of 40.6 months (range 6–91.6), 4 (9.3%) out of 43 CFSPIDs progressed to CFTR-RD or CF. All these subjects were in the group A. Conclusions: The genetic profile could help predict the risk of disease evolution in CFSPIDs carrying D1152H, revealing the subjects that need a more frequent follow-up.

Updated guidance on the management of children with cystic fibrosis transmembrane conductance regulator-related metabolic syndrome/cystic fibrosis screen positive, inconclusive diagnosis (CRMS/CFSPID)

Over the past two decades there has been considerable progress with the evaluation and management of infants with an inconclusive diagnosis following Newborn Screening (NBS) for cystic Fibrosis (CF). In addition, we have an increasing amount of evidence on which to base guidance on the management of these infants and, importantly, we have a consistent designation being used across the globe of CRMS/CFSPID. There is still work to be undertaken and research questions to answer, but these infants now receive more consistent and appropriate care pathways than previously. It is clear that the majority of these infants remain healthy, do not convert to a diagnosis of CF in childhood, and advice on management should reflect this. However, it is also clear that some will convert to a CF diagnosis and monitoring of these infants should facilitate their early recognition. Those infants that do not convert to a CF diagnosis have some potential of developing a CFTR-RD later in life. At present, it is not possible to quantify this risk, but families need to be provided with clear information of what to look out for. This paper contains a number of changes from previous guidance in light of developing evidence, but the major change is the recommendation of a detailed assessment of the child with CRMS/CFSPID in the sixth year of age, including respiratory function assessment and imaging. With these data, the CF team can discuss future care arrangements with the family and come to a shared decision on the best way forward, which may include discharge to primary care with appropriate information. Information is key for these families, and we recommend consideration of a further appointment when the individual is a young adult to directly communicate the implications of the CRMS/CFSPID designation.

Bridging the Gap between Scientific Advancement and Real-World Application: Pediatric Genetic Counseling for Common Syndromes and Single-Gene Disorders

Screening and diagnostic testing for single-gene disorders and common syndromes in the pediatric setting frequently generate data that are challenging to interpret, and the ability to diagnose genetic conditions has outpaced the development of successful treatments or cures. Genetic testing is now integrated purposefully into a variety of primary and specialty care clinics, creating an increased requirement for genetic literacy among providers and patients, as well as a growing need to incorporate genetic counseling services into mainstream clinical practice. The practice of pediatric genetic counseling encompasses a unique combination of skills and training designed to address the evolving psychological, social, educational, medical, and reproductive concerns of patients and their families, which complements the multidisciplinary services of physicians, nurses, and other allied health professionals caring for patients with pediatric-onset genetic conditions. The potential range of genetic counseling needs in the pediatric setting transcends the diagnostic period. The sustained nature of pediatric care presents opportunities for development of trusting and longstanding professional relationships that permit the evolving genetic counseling needs of patients and families to be met. A discussion of cystic fibrosis, a common autosomal recessive single-gene disorder with an increasingly broad clinical spectrum and genotype-phenotype variability, serves as a useful case study to illustrate the current and emerging genetic counseling practices, goals, and challenges impacting patients and their families.

Laboratory reporting on the clinical spectrum of CFTR p.Arg117His: Still room for improvement

BACKGROUND

The clinical spectrum associated with cystic fibrosis transmembrane conductance regulator (CFTR) variant p.Arg117His is highly variable, ranging from full-blown cystic fibrosis (CF) in a small number of cases to CFTR-related disorders (CFTR-RDs) or no symptoms at all. Therefore, taking into account phenotype variability is essential for interpretation. External quality assessment (EQA) schemes can help laboratories to objectively assess the quality of genotyping and reporting by the laboratory.

METHODS

We performed a retrospective longitudinal data analysis on laboratory performance regarding the interpretation of p.Arg117His during CF EQA scheme participation. Completeness and accuracy of reporting on two mock clinical cases were each compared over time (case 1: 2005, 2007 and 2012; case 2: 2015 and 2018). These cases concerned subjects compound heterozygous for p.Phe508del and p.Arg117His in cis with 7T, but with different clinical backgrounds (family planning (case 1) versus diagnostic testing for a child (case 2)). Furthermore, we analyzed the influence of previous participations, annual test volume, accreditation status and laboratory setting on overall performance.

RESULTS

Overall performance improved over time, except during the 2007 CF EQA scheme. In addition, previous participations had a beneficial effect on laboratory performance. Accreditation status, annual test volume and laboratory setting did not significantly influence total interpretation scores.

CONCLUSIONS

In general, laboratories performed well on both cases, although reporting on the variable clinical spectrum of p.Arg117His in cis with 7T and on the disease liability of individual CFTR variants can still improve. Moreover, this study underlined the educational role of CF EQA schemes.

Cystic fibrosis in the year 2020: A disease with a new face

The autosomal recessive disease cystic fibrosis (CF) was once untreatable and deadly in childhood, but now most patients survive to adulthood. Many countries have instituted CF newborn screening because early diagnosis improves outcome. CF research has greatly intensified following the discovery of the CF transmembrane conductance regulator (CFTR) gene, which has more than 2000 different mutations. For patients with common mutations like F508del, CFTR modulators are life transforming and may even prevent major complications if started early in childhood. For some patients with rare CFTR mutations, a treatment path still needs to be developed. Conclusion: This review provides a general update on CF, including screening and current and future treatment.

Phenotype of children with inconclusive cystic fibrosis diagnosis after newborn screening

OBJECTIVE

To characterize the phenotypic expression of children with conductance regulator-related metabolic syndrome (CRMS)/cystic fibrosis screen positive inconclusive diagnosis (CFSPID) designation after positive newborn screening, reassign labeling if applicable and better define these children's prognosis.

METHODS

A multicenter cohort with CRMS/CFSPID designation was matched with cystic fibrosis (CF)-diagnosed cohort. Cohorts were prospectively compared on baseline characteristics, cumulative data and when they reached 6 to 7 years at endpoint assessment.

RESULTS

Compared to infants with CF (n = 63), the CRMS/CFSPID cohort (n = 63) had initially lower immunoreactive trypsinogen (IRT) and sweat chloride (SC) values, delayed visits, less symptoms, and better nutritional status; during follow-up, they had fewer hospitalizations, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus identification, CF comorbidities, and treatment burden. At endpoint assessment, they presented a milder pulmonary phenotype on Brody computed tomography scores (0.0[0.0; 2.0] vs 13[2.0; 31.0]; P < .0001, respectively), Wisconsin and Brasfield chest radiograph scores, pulmonary function tests, and improved nutritional status. Among the inconclusive CF diagnosis cohort, 28 cases (44%) converted to CF diagnosis based on genotype (44%), SC (28%) or both (28%); yet, comparing those with or without final CF diagnosis, we found no differences, possibly related to their young age and mild degree of lung disease. In the total cohort, we found significant associations between Brody scores and IRT, SC values, genotype, Wisconsin and Brasfield score and spirometry.

CONCLUSIONS

The matched CRMS/CFSPID and CF cohorts showed differences in outcomes. By a mean age of 7.6 years, a high proportion of the CRMS/CFSPID cohort converted to CF. Our results highlight that monitoring at CF clinics until at least 6 years is needed as well as further studies.

Inconclusive Diagnosis after Newborn Screening for Cystic Fibrosis

An unintended consequence of newborn screening for cystic fibrosis (CF) is the identification of infants with a positive screening test but an inconclusive diagnostic testing. These infants are designated as CF transmembrane conductance regulator-related metabolic syndrome (CRMS) in the US and CF screen-positive, inconclusive diagnosis (CFSPID) in Europe. Recently, experts agreed on a unified international definition of CRMS/CFSPID which will improve our knowledge on the epidemiology and outcomes of these infants and optimize comparisons between cohorts. Many of these children will remain free of symptoms, but a number may develop clinical features suggestive of CFTR-related disorder (CFTR-RD) or CF later in life. Clinicians should to be prepared to identify these infants and communicate with parents about this challenging and stressful situation for both healthcare professionals and families. In this review, we present the recent publications on infants designated as CRMS/CFSPID, including the definition, the incidence across Europe, the assessment of the CFTR protein function, the outcomes with the rates of conversion to a final diagnosis of CF and their management.

Psychological Impact on Parents of an Inconclusive Diagnosis Following Newborn Bloodspot Screening for Cystic Fibrosis: A Qualitative Study

Genetic results of uncertain clinical significance are being returned to parents following newborn screening, representing a paradigm change in how society considers health and illness. 'Cystic Fibrosis screen positive, inconclusive diagnosis' (CFSPID) is a designation given to newborns with a positive screening result for, but not a definitive diagnosis of, cystic fibrosis. We explored the psychological impact of receiving a CFSPID result on parents. Five semi-structured interviews were conducted with eight parents whose children have CFSPID. Interpretative phenomenological analysis identified these themes: "The way we were told": 'diagnosis as a traumatic event' focused on how parents were distressed and dissatisfied by the initial screening result communication, 'Facing and challenging traditional ideas about health and illness' explored the emerging problem of how CFSPID does not fit the commonly accepted medical model, and 'Making certainty out of uncertainty' explored the varying strategies parents developed to adapt to the uncertainty regarding their child's prognosis. Findings suggest that CFSPID results caused parents' distress, initiated with the first communication of the result and persisting thereafter. Our data suggests approaches to the delivery of CFSPID results that may reduce the impact. Work is needed to close the gap between healthcare advances and societies commonly held medical model.

Cystic fibrosis screen positive inconclusive diagnosis (CFSPID): Experience in Tuscany, Italy

OBJECTIVE

The implementation of cystic fibrosis (CF) newborn screening (NBS) has led to identification of infants with a positive NBS test but inconclusive diagnosis classified as "CF screen positive, inconclusive diagnosis" (CFSPID). We retrospectively evaluated the prevalence and clinical outcome of CFSPID infants diagnosed by 2 NBS algorithms in the period from 2011 to 2016 in the Tuscany region of Italy.

METHODS

In 2011-2016, we assessed the diagnostic impact of DNA analysis on the NBS 4-tier algorithm [immunoreactive trypsin (IRT) - meconium lactase - IRT2 - sweat chloride (SC)]. All CFSPID patients repeated SC testing every 6 months, and CFTR gene analysis was performed (detection rate 98%). We reclassified children as: CF diagnosis in presence of at least 2 pathological SC results; healthy carrier or healthy in presence of at least 2 normal SC results for age and either 1 or 0 CF-causing mutations, respectively.

RESULTS

We identified 32 CF and 50 CFSPID cases: 20/50 (40%) were diagnosed only by the IRT-DNA-SC algorithm and 16/50 (32%) only by IRT-meconium lactase-IRT2-SC. Both protocols identified the remaining 14 cases (28%). Thirty-seven of 50 (74%) CFSPID patients had a conclusive diagnosis on December 31, 2017:5 (10%) CF, 17 (34%) healthy and 15 (30%) healthy carriers; 13/50 (26%) cases were asymptomatic with persistent intermediate SC and followed as CFSPID (CF:CFSPID ratio 2.85:1).

CONCLUSIONS

In 6 years, the CF:CFSPID ratio modified from 0.64:1 to 2.85:1, and 10% of CFSPID cases progressed to CF. Genetic analysis improved positive predictive value and identified a higher number of CFSPID infants progressing to CF.

Cystic Fibrosis: From Qualification to Lung Transplantation, a Single Center Experience

Background

Cystic fibrosis (CF) is congenital multisystem disorder, that leads to gradual deterioration of pulmonary function. Advancements in therapy of CF-related lung disease have delayed its progression. However, lung transplantation remains the only therapeutic option for majority of such patients. Aim of the study was to assess qualification process and outcome of lung transplantation as a treatment of CF patients qualified in a single center between 2011 and 2018.

Material/Methods

This retrospective study assessed 41 patients who were qualified to be treated by means of lung transplantation due to CF in Lung Transplant Program of Silesian Center for Heart Diseases between 2011 and 2018. Analysis of patients during qualification process and after lung transplantation was performed. Lung recipients were observed during 1-year follow-up by means of pulmonary function tests.

Results

1-year survival was noted among 80% of the patients; 3-year survival and 5-year survival were noted among 70% of the recipients. Mean forced expiratory volume in 1 second (FEV1) increased after lung transplantation: 21.19% at qualification; and 76.67% at 12 months after lung transplantation. Mean forced vital capacity (FVC) results also improved: 34.18% at qualification and 78.34% at 12 months after lung transplantation. The 6-minute walk test (6MWT) before and after treatment noted an increase of 175.55 m.

Conclusions

Lung transplantation improves respiratory capacity of CF patients and prolongs their life.

The increasing challenge of genetic counseling for cystic fibrosis

Genetic counseling for cystic fibrosis (CF) is challenged by intricate molecular mechanisms, complex phenotypes, and psychosocial needs. CFTR variant interpretation has become critical; this manuscript examines variant nomenclature and classes, as well as opportunities and challenges posed by genetic technologies and genotype-directed therapies. With post-graduate training in medical genetics and counseling, genetic counselors educate patients and families, facilitate testing and interpretation, and help integrate genetic information into diagnosis and treatment. They support families, ranging from carrier couples or new parents, to children understanding their disease, to adults with CF contemplating reproduction. The changing face of CF increasingly highlights the critical importance of genetic information to patients and their families. Genetic counselors are uniquely poised to translate this information in diagnostics and personalized care. Genetic counselors straddle molecular and clinical realms, helping patients adapt, plan, and gain access to appropriate therapies.

Bronchiectasis: a case-based approach to investigation and management

Bronchiectasis is a chronic respiratory disease characterised by a syndrome of productive cough and recurrent respiratory infections due to permanent dilatation of the bronchi. Bronchiectasis represents the final common pathway of different disorders, some of which may require specific treatment. Therefore, promptly identifying the aetiology of bronchiectasis is recommended by the European Respiratory Society guidelines. The clinical history and high-resolution computed tomography (HRCT) features can be useful to detect the underlying causes. Despite a strong focus on this aspect of treatment a high proportion of patients remain classified as "idiopathic". Important underlying conditions that are treatable are frequently not identified for prolonged periods of time.The European Respiratory Society guidelines for bronchiectasis recommend a minimal bundle of tests for diagnosing the cause of bronchiectasis, consisting of immunoglobulins, testing for allergic bronchopulmonary aspergillosis and full blood count. Other testing is recommended to be conducted based on the clinical history, radiological features and severity of disease. Therefore it is essential to teach clinicians how to recognise the "clinical phenotypes" of bronchiectasis that require specific testing.This article will present the initial investigation and management of bronchiectasis focussing particularly on the HRCT features and clinical features that allow recognition of specific causes.

Comparison of Nutrition and Lung Function Outcomes in Patients with Cystic Fibrosis Living in Canada and the United States

RATIONALE

A 10-year gap in the median age of survival for patients with cystic fibrosis (CF) was reported between patients living in Canada compared with patients living in the United States.

OBJECTIVES

Because both malnutrition and poor lung function are associated with an increased risk of mortality in CF, we investigated the temporal and longitudinal trends in lung function and nutrition between Canada and the United States.

METHODS

This cohort study used Canadian CF Registry and U.S. CF Foundation Patient Registry data from 1990 to 2013. A unified dataset was created to harmonize the variables collected within the two registries for the purpose of comparing outcomes between the two countries.

MEASUREMENTS AND MAIN RESULTS

We conducted three analyses: survival differences by birth cohort; population trends for FEV1 and body mass index (BMI) over time; and individual patient FEV1 and BMI trajectories. The study included a total of 37,772 patients in the United States and 5,149 patients in Canada. Patients with CF experienced significant improvements in nutritional status and lung function in both Canada and the United States during the study. In addition, the survival gap between the two countries is narrowing within younger birth cohorts. The improvements for the patients within the United States were most prominent in the BMI trajectories, where patients born after 1990 in the United States have higher BMI that has persisted over time.

CONCLUSIONS

The reasons for the observed improvements, and catch-up in the United States, are likely multifactorial and include the introduction of high-fat, high-calorie diets; introduction of newborn screening; and/or improved access to care for CF children in the United States.

The Cystic Fibrosis Foundation Patient Registry. Design and Methods of a National Observational Disease Registry

RATIONALE

The Cystic Fibrosis Foundation Patient Registry (CFFPR) is an ongoing patient registry study that collects longitudinal demographic, clinical, and treatment information about persons with cystic fibrosis (CF) in the United States. CF is a life-shortening genetic disorder that occurs in approximately 1 in 3,500 births in the United States. High-quality observational data is important for clinical research, quality improvement, and clinical management.

OBJECTIVES

To describe the data collection, patient population, and key limitations of the CFFPR.

METHODS

Inclusion criteria for the CFFPR include diagnosis with CF or a CFTR-associated disorder, care at an accredited care center program, and provision of informed consent. Data from clinic visits and hospitalizations are collected through a secure website. Loss to follow-up and generalizability were examined using several methods. The accuracy of CFFPR data was evaluated with an audit of 2012 CFFPR data compared to the medical record.

MEASUREMENTS AND MAIN RESULTS

Since 1986, the CFFPR contains the records of 48,463 individuals with CF. Participation among individuals seen at accredited care centers is high, and loss to follow-up is low. An audit of 2012 CFFPR data suggests that the CFFPR contains 95% of clinic visits and 90% of hospitalizations found in the medical record for these patients, and nearly all of the audited fields were highly accurate.

CONCLUSIONS

Registries such as the CFFPR are important tools for research, clinical care, and tracking incidence, mortality and population trends.

Cystic fibrosis in the era of precision medicine

The treatment of people with cystic fibrosis (CF) has been transformed by the availability of drugs that target the basic chloride defect in the disease. The use of drugs that target specific molecular defects embodies the goals of precision medicine, which incorporate preventive and therapeutic strategies and takes into account differences among individuals. However, the entirety of CF care, from diagnosis to understanding the clinical phenotype and developing a therapeutic strategy, depends on taking into account individual characteristics to achieve optimal outcomes. Future therapies are likely to be even more individualized ushering in a new era of precision medicine.

Guidelines for the clinical management and follow-up of infants with inconclusive cystic fibrosis diagnosis through newborn screening

Neonatal screening for cystic fibrosis (CF) can detect infants with elevated immunoreactive trypsinogen (IRT) levels and inconclusive sweat tests and/or CFTR DNA results. These cases of uncertain diagnosis are defined by (1) either the presence of at most one CF-associated cystic fibrosis transmembrane conductance regulator (CFTR) mutation with sweat chloride values between 30 and 59mmol/L or (2) two CFTR mutations with at least one of unknown pathogenic potential and a sweat chloride concentration below 60mmol/L. This encompasses various clinical situations whose progression cannot be predicted. In these cases, a sweat chloride test has to be repeated at 12 months, and if possible at 6 and 24 months of life along with extended CFTR sequencing to detect rare mutations. When the diagnosis is not definite, CFTR functional explorations may provide a better understanding of CFTR dysfunction. The initial evaluation of these infants must be conducted in dedicated CF reference centers and should include bacteriological sputum analysis, chest radiology, and fecal elastase assay. The primary care physicians in charge of these patients should be familiar with the current management of CF and should work in collaboration with CF centers. A follow-up should be performed in a CF reference center at 3, 6, and 12 months of life and every year thereafter. Any symptom indicative of CF requires immediate reevaluation of the diagnosis. These guidelines were established by the "neonatal screening and difficult diagnoses" working group of the French CF society. Their objective is to standardize the management of infants with unclear diagnosis.

Lung function decline is delayed but not decreased in patients with cystic fibrosis and the R117H gene mutation

BACKGROUND

Patients with cystic fibrosis (CF) experience variable lung disease phenotypes. The R117H mutation is often associated with preserved lung function. Our objective was to compare the rate of lung function decline in patients with the R117H mutation and patients homozygous for the F508del mutation.

METHODS

Rate of decline in percentage-of-predicted FEV₁ (ppFEV₁) was analyzed using the 2006-2010 US CF Foundation Patient Registry.

RESULTS

4-year rate of decline was slower in 156 R117H patients compared with 6251 F508del patients (-0.61 vs -2.03 ppFEV₁/year, P<0.001). Rates of decline in children were slower in R117H vs F508del patients (6-12-year-olds: +0.73 vs -1.91 ppFEV₁/year, P<0.001 and 13-17-year-olds: -1.55 vs -2.66 ppFEV₁/year, P=0.046), whereas rates in adults were not significantly different (18-24-year-olds: -1.52 vs -2.12, P=0.26 and ≥25-year-olds: -1.17 vs -1.40, P=0.33).

CONCLUSIONS

These findings are consistent with a delayed onset, but ultimately similar progression, of lung disease in R117H compared with homozygous F508del patients.

The diagnosis of cystic fibrosis

Establishing the diagnosis of cystic fibrosis (CF) is straight forward in the majority of patients: they present with a clear clinical picture (most frequently chronic respiratory symptoms plus malabsorption), the sweat chloride value is>60mmol/L and two known disease causing CFTR mutations are identified. In less than 5% of subjects, mainly those with a milder or limited phenotype, the diagnostic process is more complex, because initial diagnostic test results are inconclusive: sweat chloride concentration in the intermediate range, less than 2 CF causing mutations identified or both. These patients should be referred to expert centers where bioassays of CFTR function like nasal potential difference measurement or intestinal current measurement can be done. Still, in some patients, despite symptoms compatible with CF and some indication of CFTR dysfunction (e.g. only intermediate sweat chloride value), diagnostic criteria are not met (e.g. only 1 CFTR mutation identified). For these subjects, the term CFTR related disorder (CFTR-RD) is used. Patients with disseminated bronchiectasis, congenital bilateral absence of the vas deferens and acute or recurrent pancreatitis may fall in this category. CF has a very wide disease spectrum and increasingly the diagnosis is being made during adult life, mainly in subjects with milder phenotypes. In many countries, nationwide CF newborn screening (NBS) has been introduced. In screen positive babies, the diagnosis of CF must be confirmed by a sweat test demonstrating a sweat chloride concentration above 60mmol/L. To achieve the benefit of NBS, every baby in whom the diagnosis of CF is confirmed must receive immediate follow-up and treatment in a CF reference center. CF NBS is not full proof: some diagnoses will be missed and in some babies the diagnosis cannot be confirmed nor ruled out with certainty. Screening algorithms that include gene sequencing will detect a high number of such babies that are screen positive with an inconclusive diagnosis (CFSPID). Even in 2016, the most reliable and widely available diagnostic test for CF is the measurement of chloride concentration in sweat. The method of choice is sweat induction by pilocarpine iontophoresis, followed by sweat collection on a gauze or filter paper or in a Macroduct coil. Since mutation specific therapies have become available, it is important to identify the mutations responsible for CF in each individual patient.

Genomic sequencing in cystic fibrosis newborn screening: what works best, two-tier predefined CFTR mutation panels or second-tier CFTR panel followed by third-tier sequencing?

PurposeThe purpose of this study was to model the performance of several known two-tier, predefined mutation panels and three-tier algorithms for cystic fibrosis (CF) screening utilizing the ethnically diverse California population.MethodsThe cystic fibrosis transmembrane conductance regulator (CFTR) mutations identified among the 317 CF cases in California screened between 12 August 2008 and 18 December 2012 were used to compare the expected CF detection rates for several two- and three-tier screening approaches, including the current California approach, which consists of a population-specific 40-mutation panel followed by third-tier sequencing when indicated.ResultsThe data show that the strategy of using third-tier sequencing improves CF detection following an initial elevated immunoreactive trypsinogen and detection of only one mutation on a second-tier panel.ConclusionIn a diverse population, the use of a second-tier panel followed by third-tier CFTR gene sequencing provides a better detection rate for CF, compared with the use of a second-tier approach alone, and is an effective way to minimize the referrals of CF carriers for sweat testing. Restricting screening to a second-tier testing to predefined mutation panels, even broad ones, results in some missed CF cases and demonstrates the limited utility of this approach in states that have diverse multiethnic populations.

Optimization of the French cystic fibrosis newborn screening programme by a centralized tracking process

Objectives To evaluate the French cystic fibrosis newborn screening algorithm, based on data tracked by a centralized monitoring process, from 2002 to 2014. The programme aimed to attain European Standards in terms of positive predictive value, sensitivity, the ratio of screen positive patients diagnosed with cystic fibrosis to infants who screen positive but with inconclusive diagnosis (CFSPID), and time to diagnosis. Methods Retrospective analysis of programme performance, compliance with the algorithm, and changes in screening strategy. Results Modifications in the flow chart protocol improved the positive predictive value to 0.31 while maintaining the sensitivity at 0.95. Among infants diagnosed with cystic fibrosis, or identified as CFSPID, sweat test results were obtained for 94%, and two mutations were identified after exhaustive screening for the gene, when applicable, in 99.6%. The rate of pending diagnosis was very low (0.5%). The ratio of infants with cystic fibrosis:CFSPID was 6.3:1. Age at initial visit at the CF centre was ≤ 35 days, respectively, in 53%/26%. Conclusion Performances were in agreement with European standards, but timeliness of initial visit needed improvement. Our data complement an accumulating body of evidence demonstrating that attention must be paid to such ethical considerations as limiting carrier detection and inconclusive diagnosis. Newborn screening programmes should have a rigorous centralized monitoring process to warrant adjustments for improving performance to attain consensus guidelines.

[Management of infants whose diagnosis is inconclusive at neonatal screening for cystic fibrosis]

Neonatal screening for cystic fibrosis (CF) may detect infants with elevated immunoreactive trypsinogen (IRT) levels but with inconclusive sweat tests and/or DNA results. This includes cases associating (1) either the presence of at most one CF-causing mutation and sweat chloride values between 30 and 59mmol/L or (2) two CFTR mutations with at least one of unknown pathogenicity and a sweat chloride below 60mmol/L. This encompasses different clinical situations whose progression cannot be predicted. These cases require redoing the sweat test at 12 months and if possible at 6 and 24 months of life. This must be associated with extended genotyping. CFTR functional explorations can also help by investigating CFTR dysfunction. These infants must be initially evaluated in dedicated CF centers including bacteriological sputum analysis, chest radiology and fecal elastase dosage. A home practitioner must be informed of the specificity of follow-up. These infants will be reviewed in the CF center at 3, 6 and 12 months and every year. Any CF-related symptom requires reevaluation of the diagnosis. These guidelines were established by the "neonatal screening and difficult diagnoses" working group of the French CF Society. They aim to standardize management of infants with unclear diagnosis in French CF centers.

Differences in Outcomes between Early and Late Diagnosis of Cystic Fibrosis in the Newborn Screening Era

OBJECTIVES

To evaluate children with cystic fibrosis (CF) who had a late diagnosis of CF (LD-CF) despite newborn screening (NBS) and compare their clinical outcomes with children diagnosed after a positive NBS (NBS-CF).

STUDY DESIGN

A retrospective review of patients with LD-CF in New South Wales, Australia, from 1988 to 2010 was performed. LD-CF was defined as NBS-negative (negative immunoreactive trypsinogen or no F508del) or NBS-positive but discharged following sweat chloride < 60 mmol/L. Cases of LD-CF were each matched 1:2 with patients with NBS-CF for age, sex, hospital, and exocrine pancreatic status.

RESULTS

A total of 45 LD-CF cases were identified (39 NBS-negative and 6 NBS-positive) with 90 NBS-CF matched controls. Median age (IQR) of diagnosis for LD-CF and NBS-CF was 1.35 (0.4-2.8) and 0.12 (0.03-0.2) years, respectively (P <.0001). Estimated incidence of LD-CF was 1 in 45 000 live births. Compared with NBS-CF, LD-CF had more respiratory manifestations at time of diagnosis (66% vs 4%; P <.0001), a higher rate of hospital admission per year for respiratory illness (0.49 vs 0.2; P = .0004), worse lung function (forced expiratory volume in 1 second percentage of predicted, 0.88 vs 0.97; P = .007), and higher rates of chronic colonization with Pseudomonas aeruginosa (47% vs 24%; P = .01). The LD-CF cohort also appeared to be shorter than NBS-CF controls (mean height z-score -0.65 vs -0.03; P = .02).

CONCLUSIONS

LD-CF, despite NBS, seems to be associated with worse health before diagnosis and worse later growth and respiratory outcomes, thus providing further support for NBS programs for CF.