Adjunctive Systemic Corticosteroids for Pulmonary Exacerbations of Cystic Fibrosis

Intravenous antibiotics for pulmonary exacerbations in people with cystic fibrosis

BACKGROUND

Cystic fibrosis is a multisystem disease characterised by the production of thick secretions causing recurrent pulmonary infection, often with unusual bacteria. Intravenous (IV) antibiotics are commonly used in the treatment of acute deteriorations in symptoms (pulmonary exacerbations); however, recently the assumption that exacerbations are due to increases in bacterial burden has been questioned. This is an update of a previously published review.

OBJECTIVES

To establish whether IV antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis improve short-term and long-term clinical outcomes.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews and ongoing trials registers. Date of last search of Cochrane Trials Register: 19 June 2024.

SELECTION CRITERIA

Randomised controlled trials and the first treatment cycle of cross-over studies comparing IV antibiotics (given alone or in an antibiotic combination) with placebo, or inhaled or oral antibiotics for people with cystic fibrosis experiencing a pulmonary exacerbation. Studies comparing different IV antibiotic regimens were also eligible.

DATA COLLECTION AND ANALYSIS

We assessed studies for eligibility and risk of bias, and extracted data. Using GRADE, we assessed the certainty of the evidence for the outcomes lung function % predicted (forced expiratory volume in one second (FEV1) and forced vital capacity (FVC)), time to next exacerbation and quality of life.

MAIN RESULTS

We included 45 studies involving 2810 participants. The included studies were mostly small, and inadequately reported, many of which were quite old. The certainty of the evidence was mostly low. Combined intravenous antibiotics versus placebo Data reported for absolute change in % predicted FEV1 and FVC suggested a possible improvement in favour of IV antibiotics, but the evidence is very uncertain (1 study, 12 participants; very low-certainty evidence). The study did not measure time to next exacerbation or quality of life. Intravenous versus nebulised antibiotics Five studies (122 participants) reported FEV1, with analysable data only from one study (16 participants). We found no difference between groups (moderate-certainty evidence). Three studies (91 participants) reported on FVC, with analysable data from only one study (54 participants). We are very uncertain on the effect of nebulised antibiotics (very low-certainty evidence). In one study, the 16 participants on nebulised plus IV antibiotics had a lower mean number of days to next exacerbation than those on combined IV antibiotics (low-certainty evidence), but we found no difference in quality of life between groups (low-certainty evidence). Intravenous versus oral antibiotics Three studies (172 participants) reported no difference in different measures of lung function. We found no difference in analysable data between IV and oral antibiotic regimens in either FEV1 % predicted or FVC % predicted (1 study, 24 participants; low-certainty evidence) or in the time to the next exacerbation (1 study, 108 participants; very low-certainty evidence). No study measured quality of life. Intravenous antibiotic regimens compared One study (analysed as two data sets) compared the duration of IV antibiotic regimens between two groups (split according to initial antibiotic response). The first part was a non-inferiority study in 214 early treatment responders to establish whether 10 days of IV antibiotic treatment was as effective as 14 days. Second, investigators looked at whether 14 or 21 days of IV antibiotics were more effective in 705 participants who did not respond early to treatment. We found no difference in FEV1 % predicted with any duration of treatment (919 participants; high-certainty evidence) or the time to next exacerbation (information later taken from registry data). Investigators did not report FVC or quality of life. Other comparisons We also found little or no difference in lung function when comparing single IV antibiotic regimens to placebo (2 studies, 70 participants), or in lung function and time to next exacerbation when comparing different single antibiotic regimens (2 studies, 95 participants). There may be a greater improvement in lung function in participants receiving combined IV antibiotics compared to single IV antibiotics (6 studies, 265 participants; low- to very low-certainty evidence), but probably no difference in the time to next exacerbation (1 study, 34 participants; low-certainty evidence). Four studies compared a single IV antibiotic plus placebo to a combined IV antibiotic regimen with high levels of heterogeneity in the results. We are very uncertain if there is any difference between groups in lung function (4 studies, 214 participants) and there may be little or no difference to being re-admitted to hospital for an exacerbation (2 studies, 104 participants). Nine studies (417 participants) compared combined IV antibiotic regimens with a great variation in drugs. We identified no differences in any measure of lung function or the time to next exacerbation between different regimens (low- to very low-certainty evidence). There were mixed results for adverse events across all comparisons; common adverse effects included elevated liver function tests, gastrointestinal events and haematological abnormalities. There were limited data for other secondary outcomes, such as weight, and there was no evidence of treatment effect.

AUTHORS' CONCLUSIONS

The evidence of benefit from administering IV antibiotics for pulmonary exacerbations in cystic fibrosis is often poor, especially in terms of size of studies and risk of bias, particularly in older studies. We are not certain whether there is any difference between specific antibiotic combinations, and neither is there evidence of a difference between the IV route and the inhaled or oral routes. There is limited evidence that shorter antibiotic duration in adults who respond early to treatment is not different to a longer period of treatment. There remain several unanswered questions regarding optimal IV antibiotic treatment regimens.

Cystic fibrosis year in review 2023

This past year, there were many important advances for patients with cystic fibrosis (CF). Of the many publications related to CF in 2023, there was further evaluation of highly effective modulator therapy, new assessments and guidelines for clinical manifestations and therapies for CF, advances in newborn screening and diagnosis, and evaluation of outcomes for people with CF transmembrane conductance regulator-related metabolic syndrome/CF screen positive, inconclusive diagnosis. The aim of this review article is not to provide a full assessment of the wide range of articles published in 2023, but to provide a brief review of publication that may lead to changes in clinical care.

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.

Pseudomonas aeruginosa in chronic lung disease: untangling the dysregulated host immune response

Pseudomonas aeruginosa is a highly adaptable opportunistic pathogen capable of exploiting barriers and immune defects to cause chronic lung infections in conditions such as cystic fibrosis. In these contexts, host immune responses are ineffective at clearing persistent bacterial infection, instead driving a cycle of inflammatory lung damage. This review outlines key components of the host immune response to chronic P. aeruginosa infection within the lung, beginning with initial pathogen recognition, followed by a robust yet maladaptive innate immune response, and an ineffective adaptive immune response that propagates lung damage while permitting bacterial persistence. Untangling the interplay between host immunity and chronic P. aeruginosa infection will allow for the development and refinement of strategies to modulate immune-associated lung damage and potentiate the immune system to combat chronic infection more effectively.

A randomised trial of oral prednisone for cystic fibrosis pulmonary exacerbation treatment

BACKGROUND

Elevated markers of systemic and pulmonary inflammation are associated with failure to recover lung function following pulmonary exacerbations in people with cystic fibrosis (pwCF). Our aim was to determine whether adjuvant oral prednisone treatment would improve recovery of forced expiratory volume in 1 s (FEV1) % pred in CF pulmonary exacerbations not responding to antibiotic therapy.

METHODS

This was a randomised, double-blind, placebo-controlled trial in pwCF treated with intravenous antibiotics for a pulmonary exacerbation. At day 7, those who had not returned to >90% baseline FEV1 % pred were randomised to adjuvant prednisone 1 mg·kg-1 twice daily (maximum 60 mg·day-1) or placebo for 7 days. The primary outcome was the difference in proportion of subjects who recovered >90% baseline FEV1 % pred at day 14 of i.v. antibiotic therapy.

RESULTS

173 subjects were enrolled, with 76 randomised. 50% of subjects in the prednisone group recovered baseline FEV1 on day 14 compared with 39% of subjects in the placebo group (difference of 11%, 95% CI -11-34%; p=0.34). The mean±sd change in FEV1 % pred from day 7 to day 14 was 6.8±8.8% predicted in the prednisone group and 4.6±6.9% predicted in the placebo group (mean difference 2.2% predicted, 95% CI -1.5-5.9%; p=0.24). Time to subsequent exacerbation was not prolonged in prednisone-treated subjects (hazard ratio 0.83, 95% CI 0.45-1.53; p=0.54).

CONCLUSIONS

This study failed to detect a difference in FEV1 % pred recovery between adjuvant oral prednisone and placebo treatment in pwCF not responding at day 7 of i.v. antibiotic therapy for pulmonary exacerbations.