Learning objectives: Reading this article will reinforce the reader's awareness of the relationship between adherence and treatment outcome, of the causes of nonadherence, of methods of measurement, and of steps toward successful intervention.
Data sources: Articles on adherence to asthma therapy were reviewed. A MEDLINE database using subject keywords was searched from 1990 through 1997.
Study selection: Pertinent articles were chosen, with preferential presentation of results from controlled studies.
Results: There is no evidence of recent improvement in the rates of nonadherence, and patients continue on average to take about 50% of prescribed medication. Nonadherence assessment is most accurate when it can be measured objectively, and relies neither on patient report nor physician estimate. The consequences of nonadherence are measured in patient suffering, financial cost, and serious compromise of clinical trial outcomes. Underlying causes of nonadherence are traced to characteristics of the disease, treatment, patient, and caregiver system.
Conclusion: Improved adherence will lead to improved disease control, but only if medical care systems encourage and support the allocation of sufficient resources to allow barriers to self-management to be discussed and solutions negotiated. Attempts to improve adherence outside of the caregiver-patient relationship are less likely to succeed. Special programs for difficult-to-manage patients are necessary to change behavior, although significant illness improvement and cost savings are likely to result.