M.L. is a 58-year-old man with poorly controlled hypertension; he has been prescribed 100 mg of metoprolol twice daily. He says he is so tired when he gets home at night that he usually goes to bed without taking the second dose of his medication.
What methods are effective at improving adherence to treatment in patients with hypertension?
The most effective strategy to improve patient compliance with antihypertensive medication is to simplify the dosing regimen. There is more limited evidence to support a variety of motivational strategies. Patient education alone is ineffective.
Background. Lack of adherence to blood pressure–lowering medication is a major reason for poor control of hypertension worldwide. Interventions to improve adherence to antihypertensive medication have been evaluated in randomized trials, but it is unclear which interventions are effective.
Objectives. To determine the effectiveness of interventions aimed at increasing adherence to blood pressure–lowering medication in adults.
Search Strategy. The authors1 performed an all-language search of all articles in the Cochrane Controlled Trials Register, MEDLINE, EMBASE, and CINAHL in April 2002.
Selection Criteria. The authors selected randomized clinical trials (RCTs) of interventions to increase adherence to blood pressure–lowering medication in adults with essential hypertension, with adherence to medication and blood pressure control as outcomes.
Data Collection and Analysis. Two authors extracted data independently and in duplicate and assessed each study according to the criteria outlined by the Cochrane Collaboration Handbook.
Primary Results. The authors included 38 studies testing 58 different interventions and containing data on 15,519 patients. The studies were conducted in nine countries between 1975 and 2000. The duration of follow-up ranged from two to 60 months. Due to heterogeneity between studies in terms of interventions and the methods used to measure adherence, results were not pooled. Simplifying dosing regimens increased adherence in seven out of nine studies (relative increase in adherence, 8 to 19.6 percent). Motivational strategies were successful in 10 of 24 studies, with generally small increases in adherence, up to 23 percent. Complex interventions involving more than one technique increased adherence in eight out of 18 studies, ranging from 5 to 41 percent. Patient education alone seemed largely unsuccessful.
Reviewers’ Conclusions. Reducing the number of daily doses appears to be effective in increasing adherence to blood pressure–lowering medication and should be tried as a first-line strategy, although there is less evidence of an effect on blood pressure reduction. Some motivational strategies and complex interventions appear promising, but more evidence is needed from RCTs.
These summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the originalreviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minorediting changes have been made to the text (http://www.cochrane.org).
Treatment of high blood pressure with medication can reduce the risk of stroke by 31 to 45 percent, and myocardial infarction by 8 to 23 percent.2,3 Despite this benefit, control of hypertension in the ambulatory setting is suboptimal. Adherence to treatment regimens for high blood pressure is estimated to be between 50 and 70 percent.4
Simplification of treatment is the most effective intervention. Medications that can be taken once a day (see accompanying table) are preferred, as long as the increased cost of a once-daily formulation does not pose a barrier to adherence. If the patient is taking other medications, consider recommending that all be taken at the same time of day. Medications with special requirements (e.g., bedtime dosing, avoiding meals) should be used only if alternatives are unavailable or atypical circumstances exist. It is important to note that while dosing simplification improved adherence in seven out of nine studies, only one study showed an improvement in adherence and in systolic blood pressure by changing from twice-daily to once-daily dosing. No study found an improvement in diastolic blood pressure with improved adherence.
|Angiotensin-converting enzyme inhibitors|
|Angiotensin II antagonists|
|Calcium channel blockers|
Patient-centered motivational counseling should identify barriers to medication compliance and include patients in prescribing decisions. Successful motivational strategies include daily reminder charts, training in self-determination, packaging medications in combination, social and family support, telephone calls from nurses, electronic medication aid caps, and telephone-linked computer counseling.