- Most studies of asthma self-management do not permit retrospective isolation of the independent effects of a written action plan or peak flow meter use.
- Studies designed to isolate the effect of these self-care activities are generally underpowered or prone to systematic bias.
- Available evidence suggests that peak flow meters and written action plans do not have a large impact on outcomes when applied to the general population of asthmatics.
- These interventions are most likely to have beneficial effect when applied to selected populations, particularly patients with high baseline utilization.
Self-management skills are widely promoted by health plans and specialty societies with the expectation that they will improve care. The 1997 National Heart, Lung, and Blood Institute guidelines on treating asthma emphasize self-management,1 although they do not recommend specific programs. To maximize therapeutic effectiveness, it would be useful to know which components of patient self-management improve outcomes. Written action plans and peak flow meters are commonly used in asthma self-management programs. While these are simple, low-cost interventions for an individual, the aggregate cost for the entire population of asthmatics may be high.2
Much literature has accumulated on the effectiveness of providing asthma education alone and on programs that actively engage patients in their own care.Several systematic reviews have found that providing educational information alone has had little effect on asthma outcomes.3-5 There is evidence, though, that self-management activities are more effective than educational information alone. A recent Cochrane review of 24 trials found that self-management with regular practitioner review reduces hospi-talizations and emergency room visits.6 This review did not identify specific components contributing to improved outcomes. In contrast to the aforementioned studies on patient education, a large case-control study of children in the Kaiser Permanente System,7 found that written action plans were associated with lower rates of hospitalization and emergency room use. However, such observational studies often include confounding factors and are not sufficient to establish a cause-effect relationship between written action plans and improved outcomes.
We report on a systematic review that attempts to isolate the independent effect of a written action plan on asthma outcomes. We address two key questions:
- Compared with medical management alone, does the addition of a written asthma action plan (with or without peak flow meter use) improve outcomes?
- Compared with a written action plan based on symptoms, does a written action plan based on peak flow monitoring improve outcomes?
Methods
This study is part of a broader evidence report on the management of chronic asthma prepared for the Agency of Health Care Research and Quality8. Complete details of the methodology are available in the full report8 (http://www.ahcpr.gov/clinic/epcix.htm).
Literature search and study selection
We performed a comprehensive literature search from 1980 to August 2000 using MEDLINE, Embase, the Cochrane Library, and a hand search of recent bibliographies. The search was limited to full-length, peer-reviewed articles with an English abstract. Two independent reviewers carried out each step of study selection and data abstraction. Disagreements were resolved by consensus of the two reviewers or, if necessary, by the decision of a third reviewer.
Initial study selection was limited to comparative full-length reports or abstracts in peer-reviewed medical journals, with at least 25 evaluable children or adults per arm, treated for at least 12 weeks. Relevant comparisons included a written action plan and no written action plan; a written action plan based on peak flow readings and a written action plan based on symptoms. Study designs varied: clinical trials, cohort comparisons, case-control analyses, cross-sectional evaluations, and before-after comparisons. Specific components of the management plan had to be described.
Relevant outcomes included measures of inpatient and outpatient utilization, lung function, symptoms, rescue medication or oral steroid use, and quality of life. Outcomes of greatest interest were utilization parameters, as the goals of self-management usually focus on improving these outcomes.
These initial selection criteria yielded many studies that were confounded by multiple asthma management interventions and thus did not isolate the comparisons of interest. Therefore, the research team collectively determined the study design features that would best isolate the effects of written action plans and used them as new criteria in a second round of study selection. The studies thus selected satisfied 4 criteria: 1) randomization of patients; (2) delivery of the same interventions to experimental and control groups, except that the experimental group also received a written action plan; (3) delivery of the same interventions to experimental and control groups, except that one group received a written action plan based on peak flow meter readings, and the comparison group received a written action plan based on symptom monitoring; and 4) inclusion of a written action plan that met our specified definition.