The review concluded that evidence from the most rigorous studies available showed that spinal manipulation was not an effective treatment in alleviating the symptoms or signs of asthma. The author's conclusions reflected the evidence presented, although it should be borne in mind the conclusions are based on a small number of trials with small sample sizes.

To evaluate the effectiveness of spinal manipulation for the treatment of asthma.

AMED, EMBASE, MEDLINE and CINAHL databases were searched without language restriction from inception to September 2008 for published studies. Search terms were reported. Bibliographies of review articles, other relevant publications and departmental files were handsearched. Abstracts were excluded from the review.

Randomised clinical trials (RCTs) that evaluated the effectiveness of spinal manipulation in people of any age as a treatment for asthma, compared with any control group, were eligible for inclusion. To be included, trials had to include a clinical outcome (lung function, symptoms, medication usage).

In the included trials, the interventions were high velocity, low amplitude directional thrust to dysfunctional joints of the spine by a chiropractor. Control groups received sham manipulation. Treatment ranged from one to three months. Participants were treated for mild, moderate or chronic childhood asthma. Outcomes reported were lung function tests, symptom scores, bronchodilator use, bronchial reactivity, peak expiratory flow, patient related symptoms and medication use.

The author did not state how many reviewers selected studies for inclusion.

Two reviewers independently assessed validity using the Jadad score, assessing randomisation, blinding and withdrawals or drop-outs (maximum score of 5 points).

Two reviewers independently performed the data extraction.

Data were combined in a narrative synthesis.

Three RCTs (n=158 patients, range 31 to 91) were included in the review. All the included trials were of excellent methodological quality and scored 5 points.

There were no significant differences between spinal manipulation groups and sham treatment groups for lung function or subjective symptoms of asthma (three RCTs).

Evidence from the most rigorous studies available reported that spinal manipulation was not an effective treatment in alleviating the symptoms or signs of asthma.

The review addressed a clear question with appropriate inclusion criteria. Several relevant sources were searched without language restriction, but only published studies were eligible for inclusion; therefore, there may be the potential for publication bias. Appropriate methods were used to reduce reviewer error and bias for validity assessment and data extraction, but it was unclear whether these methods were applied to the selection of studies.

Trial quality was assessed using an appropriate tool, but it should be noted that evaluation of allocation concealment was not part of the assessment. A narrative synthesis was appropriate given the differences between studies in terms of treatment and outcomes, although few details were reported for participants.

The author's conclusions reflected the evidence presented, although it should be borne in mind that the conclusions are based on a small number of trials with small sample sizes.

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

Research: The author stated that the onus is on clinicians or organisations who "imply" spinal manipulation is an effective therapy for asthma to fund, conduct and publish rigorous trials, which should be aimed at reducing methodological bias, and ensuring that treatment is administered optimally and outcomes, such as relevant clinical endpoints, are reported using validated measures.

Not stated.

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.