Reevaluating approaches to cystic fibrosis pulmonary exacerbations

Changing Epidemiology of Pediatric Pulmonary Exacerbations in Cystic Fibrosis

RATIONALE

The introduction of elexacaftor/tezacaftor/ivacaftor (ETI), a highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy, to younger ages and the COVID-19 pandemic have significantly reduced pulmonary exacerbations requiring hospitalization among children with CF.

OBJECTIVE

To assess demographic and clinical characteristics of children and young adults with CF hospitalized for pulmonary exacerbations before and after pediatric ETI approval.

METHODS

A retrospective chart review was conducted at five United States CF Foundation-accredited care centers. Hospitalization data from children and young adults with CF in 2018 and 2022 were analyzed.

RESULTS

Hospitalizations decreased from 471 cases (241 individuals) in 2018 to 163 cases (110 individuals) in 2022. The racial distribution shifted, with more hospitalized patients identifying as people of color in 2022 (28% vs. 14%; p = 0.018). A greater proportion of hospitalized children in 2022 had two non-F508del mutations compared with children hospitalized in 2018 (38% vs. 19%) and were less likely to be infected with methicillin-resistant Staphylococcus aureus (MRSA). Comparing 2022-2018, children on CFTR modulator therapy, including ETI (76%), showed reduced infections with Pseudomonas aeruginosa and Achromobacter xylosoxidans.

CONCLUSIONS

The decline in hospitalizations for pulmonary exacerbations likely reflects the benefits of ETI therapy, as a higher proportion of children and young adults hospitalized in 2022 had two non-F508del mutations and were not eligible for ETI. A greater percentage of those hospitalized in 2022 identified as belonging to minority racial groups, highlighting ongoing health disparities in the ETI era. Additionally, there were notable changes in the microbiological characteristics between 2018 and 2022.

Treatment of small as well as large declines in lung function enhances recovery to baseline in people with CF

BACKGROUND

The benefit of antibiotic treatment of acute drops in FEV1 percent predicted (FEV1pp) has been clearly established, but data from the early 2000s showed inconsistent treatment. Further, there is no empirical evidence for what magnitude of drop is clinically significant.

METHODS

We used data from the CF Foundation Patient Registry (CFFPR) from 2016 to 2019 to determine the association between treatment (any IV antibiotics, only oral or newly prescribed inhaled antibiotics, or no antibiotic therapy) following a decline of ≥5% from baseline FEV1pp and return to 100% baseline FEV1pp days using multivariable logistic regression including an interaction between the magnitude of decline and treatment category.

RESULTS

Overall, 16,495 PWCF had a decline: 16.5% were treated with IV antibiotics, 25.0% non-IV antibiotics, and 58.5% received no antibiotics. Antibiotic treatment was more likely for those with lower lung function, history of a positive PA culture, older age and larger FEV1 decline (p < 0.001). Treatment with IV antibiotics or oral/inhaled antibiotics was associated with a higher odds of recovery to baseline compared to no treatment across all levels of decline, including declines of 5%-10%.

CONCLUSIONS

A large proportion of acute drops in FEV1pp continue to be untreated, especially in younger patients and those with higher baseline lung function. Acute drops as small as 5% predicted are less likely to be recovered if antibiotic treatment is not prescribed. These findings suggest the need for more aggressive antimicrobial treatment of acute drops in FEV1, including those of a magnitude previously believed to be associated with self-recovery.

Home-spirometry exacerbation profiles in children with cystic fibrosis

BACKGROUND

Pulmonary exacerbations (PEx) are strong predictors of respiratory disease progression in children with cystic fibrosis (CwCF) and may be associated with persistent decreased lung function after acute management. Telemonitoring devices can be used for early detection and monitoring of PEx, but its utility is debated.

RESEARCH QUESTION

Which symptoms and telemonitoring spirometry characterics are related to outcome dynamics following initial PEx management?

METHODS

This retrospective study included CwCF followed at Bordeaux University Hospital, France. All severe PEx episodes treated with intravenous (IV) antibiotics (ATB) between 1 January 2017 and 31 December 2021 in CwCF using home telemonitoring were analyzed. Symptoms and home spirometry data were collected 45 days before and up to 60 days after each IV ATB course. We defined three response profiles based on terciles of baseline forced expiratory volume in 1 s (FEV1 ) recovery.

RESULTS

A total of 346 IV ATB courses for PEx were administered to 65 CwCF during the study period. The drop in FEV1 became significant 8 days before IV ATB initiation. Forty-one percent of IV ATB courses failed to restore baseline FEV1 . The magnitude of FEV1 drop and a greater delay in the initiation of treatment correlated with a low response level. On the 14th day of the IV treatment, a FEV1 recovery less than 94% of baseline was associated with a nonresponder profile.

INTERPRETATION

Home spirometry may facilitate the early recognition of PEx to implement earlier interventions. This study also provides an outcome lung function threshold which identifies low responders to IV ATB.

Routine spirometry in cystic fibrosis patients: impact on pulmonary exacerbation diagnosis and FEV1 decline

OBJECTIVE

Pulmonary disease in cystic fibrosis (CF) is characterised by recurrent episodes of pulmonary exacerbations (PExs), with acute and long-term declines in lung function (FEV1). The study sought to determine whether routine spirometry increases the frequency of PEx diagnosis, resulting in benefits to long-term pulmonary function.

METHODS

CF patients in the 5- to 18-year age bracket were followed for 1 year, during which they underwent spirometry before every medical visit. The main variables were the frequency of PEx diagnosis and use of antibiotics; the use of spirometry as a criterion for PEx diagnosis (a decline ≥ 10% in baseline FEV1); and median percent predicted FEV1 over time. The data were compared with those for the previous 24-month period, when spirometry was performed electively every 6 months.

RESULTS

The study included 80 CF patients. PExs were diagnosed in 27.5% of the visits, with a mean frequency of 1.44 PExs per patient/year in 2014 vs. 0.88 PExs per patient/year in 2012 (p = 0.0001) and 1.15 PExs per patient/year in 2013 (p = 0.05). FEV1 was used as a diagnostic feature in 83.5% of PExs. In 21.9% of PExs, the decision to initiate antibiotics was solely based on an acute decline in FEV1. The median percent predicted FEV1 during the follow-up year was 85.7%, being 78.5% in 2013 and 76.8% in 2012 (p > 0.05). The median percent predicted FEV1 remained above 80% during the two years after the study.

CONCLUSIONS

Routine spirometry is associated with higher rates of diagnosis and treatment of PExs, possibly impacting long-term pulmonary function.

Abnormal n-6 fatty acid metabolism in cystic fibrosis contributes to pulmonary symptoms

Cystic fibrosis (CF) is a recessively inherited fatal disease that is the subject of extensive research and ongoing development of therapeutics targeting the defective protein, cystic fibrosis transmembrane conductance regulator (CFTR). Despite progress, the link between CFTR and clinical symptoms is incomplete. The severe CF phenotypes are associated with a deficiency of linoleic acid, which is the precursor of arachidonic acid. The release of arachidonic acid from membranes via phospholipase A₂ is the rate-limiting step for eicosanoid synthesis and is increased in CF, which contributes to the observed inflammation. A potential deficiency of docosahexaenoic acid may lead to decreased levels of specialized pro-resolving mediators. This pathophysiology may contribute to an early and sterile inflammation, mucus production, and to bacterial colonization, which further increases inflammation and potentiates the clinical symptoms. Advances in lipid technology will assist in elucidating the role of lipid metabolism in CF, and stimulate therapeutic modulations of inflammation.

Predictive value of the modified Bhalla score for assessment of pulmonary exacerbations in adults with cystic fibrosis

OBJECTIVES

The objective of this study was to analyze the predictive value of the modified Bhalla score in high-resolution computed tomography (HRCT) for assessment of pulmonary exacerbations (PEx) in cystic fibrosis (CF) patients. We also describe the relationship between this score and pulmonary function test results.

METHODS

We performed a multicenter and prospective study where adult patients with CF were included consecutively over 18 months. All patients underwent HRCT with acquisition in inspiration and expiration. The results were analyzed by an expert radiologist who assigned a modified Bhalla score value. Lung function was also assessed, and clinical variables were collected. Follow-up lasted approximately 1 year, and PEx were registered.

RESULTS

The study population comprised 160 subjects selected from 360 CF patients monitored in the participating CF units. The mean age was 28 years, 47.5% were women, and mean forced expiratory volume in 1 s (FEV₁) was 67.5%. The mean global modified Bhalla score was 14.5 ± 0.31 points. Pulmonary function test (PFT) results and the modified Bhalla score correlated well, mainly forced vital capacity (FVC) and FEV₁. We constructed a statistical model based on the overall Bhalla score to predict the number of PEx.

CONCLUSIONS

The overall modified Bhalla score can predict future PEx in CF patients. This useful tool can help to prevent PEx in higher risk patients.

KEY POINTS

• Pulmonary function test results and the modified Bhalla score correlated well with FVC and FEV₁. • The total modified Bhalla score can predict the number of exacerbations in adult CF patients. • Our findings highlight the need to establish a unified protocol for chest HRCT during the follow-up of adult patients with CF in order to anticipate possible complications and determine their impact on pulmonary function.

Influences of environmental exposures on individuals living with cystic fibrosis

INTRODUCTION

Natural, social, and constructed environments play a critical role in the development and exacerbation of respiratory diseases. However, less is known regarding the influence of these environmental/community risk factors on the health of individuals living with cystic fibrosis (CF), compared to other pulmonary disorders.

AREAS COVERED

Here, we review current knowledge of environmental exposures related to CF, which suggests that environmental/community risk factors do interact with the respiratory tract to affect outcomes. Studies discussed in this review were identified in PubMed between March 2019 and March 2020. Although the limited data available do not suggest that avoiding potentially detrimental exposures other than secondhand smoke could improve outcomes, additional research incorporating novel markers of environmental exposures and community characteristics obtained at localized levels is needed.

EXPERT OPINION

As we outline, some environmental exposures and community characteristics are modifiable; if not by the individual, then by policy. We recommend a variety of strategies to advance understanding of environmental influences on CF disease progression.