Comment: A Cochrane systematic review identified the beneficial effects of planned asthma management and education that includes a written action plan.1 These findings have now been adapted for primary care and implemented as the Asthma 3+ Visit Plan. This involves a systematic assessment of asthma symptoms, lung function, and current treatment at each visit. Treatment and management skills are optimised and the patient is given written instructions on how and when to increase treatment when asthma deteriorates (a written action plan).

A recent Cochrane review asked whether one can get the same benefits by doing less — by simply supplying a patient with a written action plan.2 The review found that the literature was inconclusive. This doesn't mean that written action plans are not effective; it means that there is not enough evidence to be able to answer the question. The result of "no evidence of effect" is completely different to "evidence of no effect".3,4 This is a crucial distinction, as many systematic reviews find insufficient evidence to be able to assess a treatment. This is a statement about our ignorance rather than a statement about whether a treatment works or not.

The review also highlights the need to carefully evaluate the control intervention. For example, the control groups in two studies in the systematic review2 received regular medical review, with assessment of severity and optimisation of inhaled steroid therapy. It is not surprising that these studies found it difficult to identify any additional effect of an action plan.

Cochrane systematic reviews conclude with recommendations for clinical practice that highlight effective treatments,1 and with recommendations for research that indicate where more information is needed.2 The review looking at just supplying patients with written action plans2 exemplifies the latter.