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Review: evidence on the effectiveness of interventions to assist patient adherence to prescribed medications is limited
  1. William M Tierney, MD
  1. Indiana University School of Medicine and the Regenstrief Institute, Inc.
 Indianapolis, Indiana, USA

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 QUESTION: In non-addicted patients with medical or mental disorders, are interventions designed to assist adherence to self administered prescribed medications effective?

    Data sources

    Studies were identified by searching Medline, CINAHL, PsycLIT, SOCIOFILE, IPA, EMBASE/Excerpta Medica, and the Cochrane Library (all from 1967 to August 2001). Bibliographies of relevant articles were reviewed, and authors of included studies were contacted for additional trials.

    Study selection

    Studies were selected if they were unconfounded randomised controlled trials (RCTs) of interventions to improve adherence with self administered prescribed medications for a medical or psychiatric disorder, measured both medication adherence and treatment outcome, had ≥80% follow up of each group studied, and the duration of follow up for studies with positive initial findings was ≥6 months.

    Data extraction

    Data were extracted on sample size, details of intervention strategies for adherence, details of treatment for the underlying medical or mental disorder, study quality, and outcomes (adherence rates and patient outcomes).

    Main results

    33 RCTs met the selection criteria. These trials evaluated 39 unconfounded interventions. Adherence interventions were tested alone and in combination, with common themes such as more instruction for patients (oral and written material and programmed learning); increased communication and counselling (eg, compliance therapy and family intervention); increased convenience of care (eg, provision at the worksite and simplified dosing); more involvement of patients in their care through self monitoring of disease status; reminders (eg, reminder pill packaging); and reinforcement or rewards for both improved adherence and treatment response (eg, reduced frequency of visits and partial payment for blood pressure monitoring equipment). Conditions studied included hypertension (8 RCTs); schizophrenia or acute psychosis (8 RCTs); asthma, chronic obstructive pulmonary disease, or both (5 RCTs); depression (2 RCTs); human immunodeficiency virus (2 RCTs); diabetes (2 RCTs); rheumatoid arthritis (1 RCT); epilepsy (1 RCT); and hyperlipidaemia and cardiovascular disease (1 RCT).

    49% of interventions tested were associated with statistically significant increases in medication adherence, and 44% reported statistically significant improvements in treatment outcome. Adherence interventions that were effective were complex, including combinations of more convenient care, information, counselling, reminders, self monitoring, reinforcement, family therapy, and other forms of additional supervision or attention. Simple interventions that showed some success included simplified dosing regimens for those taking antihypertensive and lipid lowering medications and counselling about the importance of full adherence to antibiotic regimens reinforced by written instructions.


    In patients with medical or mental disorders, limited evidence suggests that several interventions designed to assist patients’ adherence to prescribed medications may be effective.


    Healthcare providers tend to see their job as making decisions about care and the patient’s job as carrying them out. Yet, those of us who have been prescribed daily medications have found it very difficult to comply with fitting them into our daily routines, especially for asymptomatic conditions. This difficulty is exacerbated by the increasing complexity of treatment regimens resulting from controlled trials (where there is usually great effort to maximize drug adherence), which continue to show us additional drugs that improve outcomes and those drugs are subsequently recommended for routine use. For example, 20 years ago drug therapy for heart failure consisted of digitalis and diuretics. Now, managing this condition takes 4–5 drugs, guided by a complex algorithm.1 No wonder compliance is so difficult for both physicians and their patients.

    The good news from the systematic review by McDonald et al is that several interventions, many of which are relatively easy to invoke, can increase patient adherence to drug regimens. The bad news is that it often takes efforts by several people to effect this adherence. And worse, neither private nor public insurance pays for these extra efforts. However, many of the interventions aimed at improving quality of care and patient safety2 can also be used to enhance medication adherence. If a commitment exists to enhance drug adherence as part of good prescribing, then everyone involved in providing care (eg, physicians, nurses, pharmacists, mental health counsellors, and administrators and technologists who design and maintain health care systems) should take a good, long look at the review by McDonald et al to see where they can contribute.


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    • Sources of funding: Population Health Information Project; Canadian Institutes of Health Research; Kidney Foundation of Canada.

    • For correspondence: Dr R B Haynes, McMaster University Medical Centre, Hamilton, Ontario, Canada. bhaynes{at}

    • Abstract and commentary also appear in ACP Journal Club.