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Abstract
Background: A Cochrane review concluded "Metered-dose inhalers [MDIs] with holding chamber produced outcomes that were at least equivalent to nebuliser delivery." Based on this and similar reviews of efficacy (mostly in young or middle aged patients with asthma), an expert panel advised British Columbia Pharmacare, a universal and comprehensive Provincial drug benefits program, a) to introduce a "Nebuliser-to-Inhaler Conversion" policy aimed at reducing use of nebulisers, increasing use of MDIs, and saving funds without substantially increasing other health system costs, and b) to evaluate the effectiveness of the policy using a randomized control group, a method agreeable to both proponents and critics of Pharmacare's cost-containment initiatives.
Methods: Copies of systematic reviews were given to members of the policy advisory committee. The evidence was summarized by a member with expertise in asthma. In the policy trial, 859 doctors (20% of the total) were randomized by paired street addresses or communities to the "treatment" group (n = 385; policy applied March 1, 1999) or the control group (n=474) who were offered a 6-month exemption (policy applied Sept. 1, 1999). Impact was measured using centralized administrative data on use of medications, medical services, hospitalizations, chronic care and mortality.
Results: The Cochrane review provided an important part of the evidence base, which was assembled within the tight timelines required by the Ministry of Health for the policy implementation. A letter communicating the policy to physicians cited national consensus guidelines. The policy was developed recognizing that some studies compared use of nebulisers to MDIs with holding chambers, and other studies indicated patients use MDIs poorly and infrequently with holding chambers. The evidence base was not explicit about extrapolating from studies on MDI versus nebulizers in young and middle aged asthma patients to elderly patients many of whom have chronic obstructive lung disease. Early results of the trial were available before the end of the 6-month exemption; a process for systematically incorporating new findings into the evidence base has yet to be designed.
Conclusions: Cochrane reviews can serve as part of an effective evidence base for policy development. An evidence base should be more than an unstructured justification for a policy indirectly based on evidence. We hypothesize that, liike a Cochrane review, the documentation of an evidence base is more rigorous if it is more structured, follows rules of evidence, is periodically updated and exposed to peer review. The Cochrane Collaboration can promote evidence-based policy making by developing a template, a guide and a forum for publishing evidence bases for policies.
Methods: Copies of systematic reviews were given to members of the policy advisory committee. The evidence was summarized by a member with expertise in asthma. In the policy trial, 859 doctors (20% of the total) were randomized by paired street addresses or communities to the "treatment" group (n = 385; policy applied March 1, 1999) or the control group (n=474) who were offered a 6-month exemption (policy applied Sept. 1, 1999). Impact was measured using centralized administrative data on use of medications, medical services, hospitalizations, chronic care and mortality.
Results: The Cochrane review provided an important part of the evidence base, which was assembled within the tight timelines required by the Ministry of Health for the policy implementation. A letter communicating the policy to physicians cited national consensus guidelines. The policy was developed recognizing that some studies compared use of nebulisers to MDIs with holding chambers, and other studies indicated patients use MDIs poorly and infrequently with holding chambers. The evidence base was not explicit about extrapolating from studies on MDI versus nebulizers in young and middle aged asthma patients to elderly patients many of whom have chronic obstructive lung disease. Early results of the trial were available before the end of the 6-month exemption; a process for systematically incorporating new findings into the evidence base has yet to be designed.
Conclusions: Cochrane reviews can serve as part of an effective evidence base for policy development. An evidence base should be more than an unstructured justification for a policy indirectly based on evidence. We hypothesize that, liike a Cochrane review, the documentation of an evidence base is more rigorous if it is more structured, follows rules of evidence, is periodically updated and exposed to peer review. The Cochrane Collaboration can promote evidence-based policy making by developing a template, a guide and a forum for publishing evidence bases for policies.