Association Between Number of Intravenous Antipseudomonal Antibiotics and Clinical Outcomes of Pediatric Cystic Fibrosis Pulmonary Exacerbations

Creation of a CF-specific antibiotic spectrum index (ASI) as an antimicrobial stewardship initiative

Antibiotics are frequently utilized for cystic fibrosis (CF)-related pulmonary exacerbation treatment. The antibiotic spectrum index (ASI) is an antimicrobial stewardship tool developed to compare the relative breadth of individual antibiotics. This study aimed to create two expanded CF-specific ASI scoring indices for use in antimicrobial stewardship research and clinical care. The first scoring index expanded the original ASI to include bacterial microorganisms common to CF airway infections (CF-ASI). The second scoring system only included scores for bacterial microorganisms classically identified in CF airway infections (CF-sASI). Sixty-two antibiotics were evaluated and included in the updated ASIs. When multiple antibiotics are prescribed, we proposed using an additive ASI approach whereby the sum of the individual prescribed antibiotic scores represents the total ASI score. The application of CF-focused ASIs into CF research and stewardship programs can help to optimize antibiotic benefits, minimize harms and allow for increased sustainability of antibiotic use in CF.

Update on the diagnosis and management of cystic fibrosis pulmonary exacerbations

Pulmonary exacerbations in people with cystic fibrosis are associated with significant morbidity and reduced quality of life. Pulmonary exacerbation treatment guidelines, published by an expert panel assembled by the Cystic Fibrosis Foundation nearly 15 years ago, were primarily consensus-based as there were several gaps in the evidence base. In particular, limited evidence existed regarding optimal pulmonary exacerbation treatment strategies, including duration of antibiotic therapy, treatment location, antibiotic selection, and the role of systemic corticosteroids. Over the last decade, results from observational studies and large multi-center randomized controlled trials have begun to answer important questions related to pulmonary exacerbation treatment. This review focuses on the diagnosis, etiology, and changing epidemiology of pulmonary exacerbations, and also summarizes the most recent and up-to-date studies describing pulmonary exacerbation treatment. Finally, this review provides consideration for future pulmonary exacerbation research priorities, particularly in the current highly effective modulator therapy era.

Antibiotic Regimen Changes during Cystic Fibrosis Pediatric Pulmonary Exacerbation Treatment

Rationale/Objectives: Antibiotic selection for in-hospital treatment of pulmonary exacerbations (PEx) in people with cystic fibrosis (CF) is typically guided by previous respiratory culture results or past PEx antibiotic treatment. In the absence of clinical improvement during PEx treatment, antibiotics are frequently changed in search of a regimen that better alleviates symptoms and restores lung function. The clinical benefits of changing antibiotics during PEx treatment are largely uncharacterized. Methods: This was a retrospective cohort study using the Cystic Fibrosis Foundation Patient Registry Pediatric Health Information System. PEx were included if they occurred in children with CF from 6 to 21 years old who had been treated with intravenous antibiotics between January 1, 2006, and December 31, 2018. PEx with lengths of stay <5 or >21 days or for which treatment was delivered in an intensive care unit were excluded. An antibiotic change was defined as the addition or subtraction of any intravenous antibiotic between Hospital Day 6 and the day before hospital discharge. Inverse probability of treatment weighting was used to adjust for disease severity and indication bias, which might influence a decision to change antibiotics. Results: In all, 4,099 children with CF contributed 18,745 PEx for analysis, of which 8,169 PEx (43.6%) included a change in intravenous antibiotics on or after Hospital Day 6. The mean change in pre- to post-treatment percent predicted forced expiratory volume in 1 second (ppFEV1) was 11.3 (standard error, 0.21) among events in which an intravenous antibiotic change occurred versus 12.2 (0.18) among PEx without an intravenous antibiotic change (P = 0.001). Similarly, the odds of return to ⩾90% of baseline ppFEV1 were less for PEx with antibiotic changes than for those without changes (odds ratio [OR], 0.89 [95% confidence interval (CI), 0.80-0.98]). The odds of returning to ⩾100% of baseline ppFEV1 did not differ between PEx with versus without antibiotic changes (OR, 0.94 [95% CI, 0.86-1.03]). In addition, PEx treated with intravenous antibiotic changes were associated with higher odds of future PEx (OR, 1.17 [95% CI, 1.12-1.22]). Conclusions: In this retrospective study, changing intravenous antibiotics during PEx treatment in children with CF was common and not associated with improved clinical outcomes.

Fluoroquinolone Use Among Hospitalized Children: Diagnosis-Based Stratification to Identify Stewardship Targets

Background

As FQ (fluoroquinolone) use has shifted in pediatric populations, better metrics are needed to guide targeted antibiotic stewardship interventions and limit development of adverse events and resistance, particularly in medically complex children. In this study, we identify high-utilization groups based on underlying medical conditions and describe their relative FQ use over time.

Methods

This study is a retrospective analysis of data from the Pediatric Health Information System database from 2016 to 2020. We identify high-utilization groups based on underlying medical conditions using International Classification of Diseases, Ninth or Tenth Revision codes. We delineate overall trends in the use of FQs in the inpatient setting, including rate and proportional use by each patient group.

Results

Patients with an oncology diagnosis represent a large (25%-44%) and rising proportion (+4.8%/year, P = .001) of national FQ use over the study period. Patients with intra-abdominal infections, including appendicitis, have had a significant increase in both their relative proportional use of FQs (+0.6%/year, P = .037) and proportion of FQ use per admission encounter over the study period (+0.6%/year, P = .008). Patients with cystic fibrosis represent a decreasing proportion of overall use (-2.1%/year, P = .011) and have decreasing FQ use per inpatient encounter (-0.8%/year, P = .001).

Conclusions

Patients with an oncology diagnosis and patients with an intra-abdominal infection appear to be targets for FQ stewardship. Patients with cystic fibrosis have decreasing inpatient FQ use. Key Points: This study describes fluoroquinolone use among hospitalized children from 2016 to 2020, stratified by underlying diagnoses. These trends are used to identify high-yield antibiotic stewardship targets.

Antibiotics and outcomes of CF pulmonary exacerbations in children infected with MRSA and Pseudomonas aeruginosa

BACKGROUND

Limited data exist to inform antibiotic selection among people with cystic fibrosis (CF) with airway infection by multiple CF-related microorganisms. This study aimed to determine among children with CF co-infected with methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (Pa) if the addition of anti-MRSA antibiotics to antipseudomonal antibiotic treatment for pulmonary exacerbations (PEx) would be associated with improved clinical outcomes compared with antipseudomonal antibiotics alone.

METHODS

Retrospective cohort study using data from the CF Foundation Patient Registry-Pediatric Health Information System linked dataset. The odds of returning to baseline lung function and having a subsequent PEx requiring intravenous antibiotics were compared between PEx treated with anti-MRSA and antipseudomonal antibiotics and those treated with antipseudomonal antibiotics alone, adjusting for confounding by indication using inverse probability of treatment weighting.

RESULTS

943 children with CF co-infected with MRSA and Pa contributed 2,989 PEx for analysis. Of these, 2,331 (78%) PEx were treated with both anti-MRSA and antipseudomonal antibiotics and 658 (22%) PEx were treated with antipseudomonal antibiotics alone. Compared with PEx treated with antipseudomonal antibiotics alone, the addition of anti-MRSA antibiotics to antipseudomonal antibiotic therapy was not associated with a higher odds of returning to ≥90% or ≥100% of baseline lung function or a lower odds of future PEx requiring intravenous antibiotics.

CONCLUSIONS

Children with CF co-infected with MRSA and Pa may not benefit from the addition of anti-MRSA antibiotics for PEx treatment. Prospective studies evaluating optimal antibiotic selection strategies for PEx treatment are needed to optimize clinical outcomes following PEx treatment.

Inflammation and Infection in Cystic Fibrosis: Update for the Clinician

Inflammation and infection play an important role in the pathophysiology of cystic fibrosis, and they are significant causes of morbidity and mortality in CF. The presence of thick mucus in the CF airways predisposes to local hypoxia and promotes infection and inflammation. A vicious cycle of airway obstruction, inflammation, and infection is of critical importance for the progression of the disease, and new data elucidate the different factors that influence it. Recent research has been focused on improving infection and inflammation in addition to correcting the basic gene defect. This review aims to summarize important advances in infection and inflammation as well as the effect of new treatments modulating the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein. New approaches to target infection and inflammation are being studied, including gallium, nitric oxide, and phage therapy for infection, along with retinoids and neutrophil elastase inhibitors for inflammation.

Novel Applications of Biomarkers and Personalized Medicine in Cystic Fibrosis

As routine care in cystic fibrosis (CF) becomes increasingly personalized, new opportunities to further focus care on the individual have emerged. These opportunities are increasingly filled through research in tools aiding drug selection, drug monitoring and titration, disease-relevant biomarkers, and evaluation of therapeutic benefits. Herein, we will discuss such research tools presently being translated into the clinic to improve the personalization of care in CF.

The Elusive Role of Airway Infection in Cystic Fibrosis Exacerbation

Cystic fibrosis (CF) pulmonary exacerbations (PEx) are clinical events that commonly result in increased treatment burden, decreased quality of life, and accelerated lung disease progression. CF PEx have historically been approached as though dealing with acute infections, and antibiotic treatments have been associated with improved outcomes. In this review, we discuss data supporting a causal role of CF airway infection in PEx as well studies that highlight our knowledge gaps in regard to PEx definitions, pathophysiology, and optimal treatment approaches. In the era of highly effective cystic fibrosis transmembrane conductance regulator modulator therapy, and the continually increasing health and longevity of persons with CF, a better understanding of PEx and further optimization of PEx antibiotic treatment approaches are needed.

Antipseudomonal treatment decisions during CF exacerbation management

BACKGROUND

Cystic fibrosis (CF) pulmonary exacerbation (PEx) treatment guidelines suggest that Pseudomonas aeruginosa (Pa) airway infection be treated with two antipseudomonal agents.

METHODS

We retrospectively studied treatment responses for STOP2 PEx treatment trial (NCT02781610) participants with a history of Pa infection. Mean lung function and symptom changes from intravenous (IV) antimicrobial treatment start to Visit 2 (7 to 10 days later) were compared between those receiving one, two, and three+ antipseudomonal classes before Visit 2 by ANCOVA. Odds of PEx retreatment with IV antimicrobials within 30 days and future IV-treated PEx hazard were modeled by logistic and Cox proportional hazards regression, respectively. Sensitivity analyses limited to the most common one-, two-, and three-class regimens, to only IV/oral antipseudomonal treatments, and with more stringent Pa infection definitions were conducted.

RESULTS

Among 751 participants, 50 (6.7%) were treated with one antipseudomonal class before Visit 2, while 552 (73.5%) and 149 (19.8%) were treated with two and with three+ classes, respectively. Females and participants with a negative Pa culture in the prior month were more likely to be treated with a single class. The most common single, double, and triple class regimens were beta-lactam (BL; n = 42), BL/aminoglycoside (AG; n = 459), and BL/AG/fluoroquinolone (FQ; n = 73). No lung function or symptom response, odds of retreatment, or future PEx hazard differences were observed by number of antipseudomonal classes administered in primary or sensitivity analyses.

CONCLUSIONS

We were unable to identify additional benefit when multiple antipseudomonal classes are used to treat PEx in people with CF and Pa.

Clinical Outcomes of Antipseudomonal versus Other Antibiotics Among Children with Cystic Fibrosis without Pseudomonas aeruginosa

RATIONALE

Antibiotic selection for pulmonary exacerbation (PEx) management in children with CF is typically guided by prior respiratory culture results. While antipseudomonal antibiotics are often used in children with chronic Pseudomonas aeruginosa (Pa) airway infection, no data exist to guide antibiotic selection in children who are culture negative for Pa for ≥1 year.

OBJECTIVES

To determine among children classified as 1-, 2-, or 3-years Pa-negative if PEx treatment with at least 1 oral and/or intravenous anti-Pa antibiotic is associated with improved clinical outcomes compared to treatment with antibiotics not effective against Pa.

METHODS

Retrospective cohort study using the linked CF Foundation Patient Registry-Pediatric Health Information System (CFFPR-PHIS) database. We included children 6-21 years old hospitalized between 2008-2018 consistently culture-negative for Pa 1 year prior to a study PEx. Children were classified as 1- or 2-years Pa-negative if their last Pa-positive culture occurred in the 13-24 months or 25-36 months prior to a study PEx, respectively, with all subsequent cultures negative for Pa. Children classified as 3-years Pa-negative had no Pa-positive cultures in the 36 months prior to a study PEx. Inverse probability of treatment weighted linear or logistic regression models were used to compare clinical outcomes (pre- to post-PEx forced expiratory volume in one second, odds of returning to ≥90% of baseline lung function, and odds of having a future PEx) between anti-Pa and non-anti-Pa antibiotic strategies.

RESULTS

Among all children included in the linked dataset, 1,290 children with 2,347 PEx were eligible for analysis. Among all study PEx, 530, 326, and 1,491 PEx were classified as 1-, 2-, or 3-years Pa-negative, respectively, and anti-Pa antibiotics were administered in 79%, 67%, and 66% of all PEx classified as 1-, 2-, or 3-years Pa-negative, respectively. For all Pa-negative groups, when compared to non-anti-Pa antibiotic regimens, anti-Pa antibiotic treatment was not associated with greater improvement in any studied clinical outcomes.

CONCLUSIONS

Despite its common use, including antibiotics effective against Pa may provide no additional benefit for PEx treatment among children who are Pa-negative for at least 1 year prior. Prospective trials are warranted to directly test this hypothesis.