National Heart, Lung, and Blood Institute (NHLBI) guidelines for asthma management recommend that anti-inflammatory medications be the foundation of pharmacotherapy for persistent asthma in view of the importance of inflammation in asthma pathophysiology. For moderate or severe persistent asthma, dual-controller regimens (ie, combinations of 2 or more therapies with complementary mechanisms of action) are advised. The past decade has seen an explosion of research on dual-controller options for asthma therapy. This issue, which is composed of 3 review articles, discusses the sources of information that health care providers should consider in choosing among dual-controller regimens and reviews the newest data on the dual-controller options.
Dr O'Connor's article, "Evaluating Pharmacotherapies for Asthma: Empirical Sources of Information," sets the stage for this issue by considering the best sources of information for determining value in asthma management. He reviews strengths and weakness of randomized, controlled clinical trials, which are the best source of data for inferring causality about a manipulation such as administration of a drug treatment, and observational studies, which are the best source of data for gauging how a medication performs in "real-world" clinical practice. These 2 sources of data provide complementary information about pharmacotherapies and can be useful in forming a comprehensive assessment of medication effects if their results are interpreted in the context of their strengths and weaknesses.
In his article, "Dual-Controller Regimens I: Data from Randomized, Controlled Clinical Trials," Dr Suissa reviews data from randomized, controlled clinical trials of a new dual-controller therapy for asthma, the combination of the inhaled corticosteroid fluticasone propionate, and the long-acting ß2 agonist salmeterol administered in a single delivery system. In a systematic program of controlled clinical trials, the fluticasone propionate-salmeterol combination has been compared with placebo, with either medicine administered alone, and with other combination-therapy and monotherapy regimens for asthma. The body of evidence from randomized, controlled clinical trials regarding the efficacy of this form of dual-controller therapy illustrates the value of systematic, well-controlled evaluation of a medication.
Although data from randomized, controlled clinical trials are generally regarded as the gold-standard information source about medicines, the clinical trials data alone cannot provide a comprehensive assessment of the effects of dual-controller therapy. Controlled clinical trials are not always directly applicable to clinical practice, where heterogeneous patient populations are treated and are seldom monitored as consistently or effectively as they are in clinical trials. In his article, "Dual-Controller Regimens II: Observational Data," Dr Blaiss considers evidence from observational studies assessing the effects of dual-controller regimens that include a long-acting ß2 agonist and those that include a leukotriene modifier. Observational studies assess the effects of medication as they are used outside the confines of a clinical trial. By considering effects of medicines on variables such as health care costs, emergency-room visits, and other categories of health care use, observational studies help to bridge the gap between clinical trials and clinical practice.
The data reviewed in this issue illustrate the importance of considering complementary information from multiple empirical sources in forming judgments about pharmacotherapies for asthma. Considered in aggregate, the data from controlled clinical trials and observational studies yield important practical information for the health care provider choosing among dual-controller options with unique features and benefits.
A companion slide set with contents mirroring those of the publication articles is available by business-reply card. The slide set is intended for health care providers' use in disseminating the information in this publication to others who provide respiratory care.
*Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins Asthma and Allergy Center.