CRD summary

This review assessed the relationship between inhaled corticosteroid dose and bronchial hyperresponsiveness in patients with asthma. The authors concluded that high doses conferred greater improvements than low doses. The conclusions appear to follow from the evidence presented but it is difficult to comment on their reliability because of methodological and reporting limitations in the review.

Authors' objectives

To determine whether a dose-response effect exists between inhaled corticosteroids and bronchial hyper-responsiveness (BHR) in asthmatic patients.

Searching

MEDLINE, databases on BIDS, and the Cochrane Library were searched up to May 2001; the search terms were listed in the review. The search was limited to studies which had at least an English abstract.

Study selection

Assessment of study quality

The authors did not state that they assessed validity.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

Data were extracted on the steroid dose, doubling dose protection, with 95% confidence interval (CI) compared with placebo, bronchial stimulant, number of patients in the study and dosing of inhaled corticosteroid. The doses of fluticasone and mometasone were doubled to achieve a microgram equivalent dose to beclomethasone and budesonide. For comparison purposes, the doses of the inhaled corticosteroid were categorised as low/medium (less than 1,000 microg) or high (at least 1,000 microg).

Methods of synthesis

Results of the review

Twenty-five RCTs with 963 participants were included in the review. Four trials were subdivided as data were available for a different bronchial challenge stimulus or different dose of inhaled corticosteroid. There were 18 low/medium-dose comparisons and 12 high-dose comparisons.

Compared with placebo, the estimated doubling dose/dilution shift for low/medium- and high-dose categories were 1.25 (95% CI: 1.08, 1.42) and 2.16 (95% CI: 1.88, 2.44), respectively.

Authors' conclusions

High doses of inhaled corticosteroids conferred greater improvements in BHR than low doses.

CRD commentary

The review could have been of higher quality with regard to the reporting of the review process, the validity assessment, and the assessment of heterogeneity for the included studies. The research question was clear, as were the inclusion and exclusion criteria. The literature search was limited in that it did not search EMBASE nor report any additional searches of bibliographies or unpublished literature sources. The review process could have been clearer in reporting who performed the data extraction and whether the validity of the included studies was assessed. The meta-analyses appear to have been appropriate, but statistical and clinical heterogeneity was not reported. The conclusions appear to follow from the results presented.

Implications of the review for practice and research

The authors did not state any implications for practice or further research.

Funding

University of Dundee.

Bibliographic details

Currie G P, Fowler S J, Lipworth B J. Dose response of inhaled corticosteroids on bronchial hyperresponsiveness: a meta-analysis. Annals of Allergy, Asthma and Immunology 2003; 90(2): 194-198. [PubMed: 12602665]

Indexing Status

Subject indexing assigned by NLM

MeSH

Administration, Inhalation; Anti-Asthmatic Agents /administration & dosage /therapeutic use; Anti-Inflammatory Agents /administration & dosage /therapeutic use; Asthma /drug therapy; Bronchial Hyperreactivity /drug therapy /physiopathology; Bronchial Provocation Tests; Bronchoconstrictor Agents /diagnostic use; Dose-Response Relationship, Drug; Randomized Controlled Trials as Topic /methods; Steroids; Treatment Outcome

AccessionNumber

12003000534

Database entry date

31/08/2004

Record Status

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.