This was a review of randomised controlled trials in cystic fibrosis where quality of life (QoL) was measured. The authors stated that this review highlights many of the pitfalls of QoL measurement in clinical trials of cystic fibrosis, a conclusion which follows from the available evidence. They also provided constructive information concerning the design and reporting of trials measuring QoL.

To review randomised controlled trials (RCTs) of interventions for the treatment of cystic fibrosis where quality of life (QoL) was measured.

MEDLINE, EMBASE and ISI Web of Science were searched for studies published in the English language from January 1991 to December 2004; the search terms were reported. Cochrane reviews published before December 2004 were handsearched for additional references.

Study designs of evaluations included in the review

RCTs were eligible for inclusion.

Specific interventions included in the review

There were no inclusion criteria relating to the intervention. The included interventions were antibiotics, steroids, mucolytic therapies, exercise and pancreatic enzymes.

Participants included in the review

Studies where all the participants had cystic fibrosis were eligible for inclusion. Adults and children were included in the study samples.

Outcomes assessed in the review

Studies measuring QoL or well-being were eligible for inclusion. The included studies used the Quality of Well-being Scale, Cystic Fibrosis Questionnaire, Chronic Disease Respiratory Questionnaire (CRQ) and ad hoc scales.

How were decisions on the relevance of primary studies made?

Two reviewers independently assessed studies for inclusion.

The authors recorded the following study details, which may have been used to indicate quality: quality of scale description and scoring methods; justification of sample size; quality of summary statistics for QoL and analysis; discussion of clinical importance of findings and methodological quality.

The authors did not state how the validity assessment was performed.

Data on factors associated with the QoL measure were extracted onto a summary sheet, e.g. quality of scale description and scoring method, and quality of summary statistic for QoL and analysis.

How were the studies combined?

The studies were combined in a narrative.

How were differences between studies investigated?

The studies were grouped by intervention. Other differences between the studies were apparent from the evidence tables and from the study descriptions.

Sixteen trials (n=2,411) were included. These investigated the efficacy of antibiotics (4 studies, n=805), home versus hospital administration of antibiotics (1 study, n=17), steroids (1 study, n=22), mucolytic therapies (6 studies, n=1,406), exercise (3 studies, n=148) and pancreatic enzymes (1 study, n=13).

All findings reported below are from secondary analyses unless otherwise stated.

Antibiotics.

Three placebo-controlled trials reported an improvement in QoL associated with the use of tobramycin (1 trial) and azithromycin (2 trials). One study found no difference in QoL with azithromycin.

Home and hospital administration of antibiotics.

One trial that used the CRQ as the primary outcome measure found intravenous antibiotics taken at home caused more problems with mastery and fatigue. However, factors associated with personal, family, sleeping, eating and total disruption were more positive.

Steroids.

No changes in well-being were associated with the use of corticosteroids, compared with placebo, in one trial.

Mucolytic therapies.

Two placebo-controlled trials of DNase found no improvements in well-being, whereas a further two studies did find an improvement in well-being that was associated with treatment. One trial found no effects associated with DNase or saline. One trial found no statistically significant improvement in well-being with normal or hypertonic saline.

Exercise.

Two trials found an improvement in QoL with exercise training programmes, whereas a third study found no difference in well-being among those participants that exercised and those that did not.

Pancreatic enzymes.

There were no differences in well-being associated with the intake of pancreatic enzymes in one trial.

This review highlights many of the pitfalls of QoL measurement in cystic fibrosis clinical trials and provides constructive information concerning the design and reporting of trials measuring QoL.

The inclusion criteria were condition-specific and clear in terms of the outcome measure and study design. Three relevant databases were searched and handsearches of relevant articles were conducted. However, the search was limited to studies published in English, thus there is a possibility of language and publication bias.

The authors discussed the quality of the included studies in some detail. The studies were appropriately combined in a narrative and differences were evident from the description of the studies. The authors' conclusions follow from the data presented.

Practice: The authors did not state any implications for practice.

Research: The authors commented on many aspects of trial methodology that should be considered in future studies, such as type of trial, sample size, QoL measure, quality of reporting and missing values.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.