Evid Based Nurs 10:24 doi:10.1136/ebn.10.1.24
  • Causation

Review: good adherence to drug therapy is associated with reduced mortality

 Q What is the relation between adherence to drug therapy and mortality?


GraphicData sources:

AMED, CINAHL, Embase/Excerpta Medica, ERIC, HealthSTAR, Medline, PsycINFO, and Web of Science (all from inception to June 2005); and references from textbooks and review articles.

GraphicStudy selection and assessment:

randomised controlled trials (RCTs) or observational studies in any language that evaluated the association between adherence to drug therapy and mortality, explained methods used to measure adherence, provided clear definitions of good adherence, and stratified patients into good and poor adherence groups. Studies that did not provide data on the number of deaths in each adherence group were excluded. 8 RCTs (n = 37 701) and 13 cohort studies (n = 9146) met the selection criteria. 8 studies were of patients with recent myocardial infarction, 7 of patients with HIV infection, and 2 of primary prevention of heart disease; the remaining studies included patients with type 2 diabetes, hyperlipidaemia, heart failure, and immune suppression after heart transplant.




Meta-analysis using a random effects model showed that good adherence overall was associated with lower mortality compared with poor adherence; similar results were found when considering adherence to placebo (table). Good adherence to beneficial drug therapy was associated with reduced mortality, whereas good adherence to harmful drug therapy was associated with increased mortality (table).


Good adherence to beneficial drug therapy or to placebo is associated with reduced mortality.

A modified version of this abstract appears in ACP Journal Club.


  1. Valerie Abbott-Mitchell, RN, MSc
  1. School of Nursing, McMaster University
 Hamilton, Ontario, Canada

      Poor adherence to drug therapy is considered an important barrier to good health outcomes. Approximately 25% of patients do not take medications as prescribed.1 Nurses are challenged to find effective interventions that lead to improved drug adherence.

      The methodologically rigorous meta-analysis by Simpson et al adds strong support for the relation between good adherence to prescribed drug therapy and positive health outcomes. The findings indicate that patients with good adherence to drug therapy or placebo have half the risk of mortality of patients with poor adherence. Moreover, the authors raise the notion of a “healthy adherer” effect and suggest that taking medication as prescribed may be a marker for overall healthy behaviour.

      The findings are particularly relevant for nurses caring for patients who are prescribed drug therapy for chronic illnesses and suggest that nurses should re-examine their role in promoting drug adherence. Haynes et al suggest that successful interventions for improving adherence may include more frequent provider-patient interactions with a focus on adherence.2 This finding highlights the importance of attending to interpersonal skills and patient-centredness in nurse-patient interactions to support drug adherence. Similarly, exploring the social contexts of patients may help nurses to identify challenges and build on individual capacities related to medication adherence,3 which may lead to better quality of life and reduced healthcare expenditures. Finally, more empirical nursing knowledge is needed about the association between nurse interpersonal skills in providing support and patient adherence to drug therapy.


      Association between adherence to drug therapy or placebo and mortality*

 Q What is the relation between adherence to drug therapy and mortality?


      • For correspondence: Dr S H Simpson, University of Alberta, Edmonton, Alberta, Canada. ssimpson{at}

      • Source of funding: no external funding.

      Free Sample

      This recent issue is free to all users to allow everyone the opportunity to see the full scope and typical content of EBN.
      View free sample issue >>

      EBN Journal Chat

      The EBN Journal Chat offers readers the opportunity to participate in discussion about research articles and commentaries from Evidence Based Nursing (EBN).

      How to participate >>

      Don't forget to sign up for content alerts so you keep up to date with all the articles as they are published.

      Navigate This Article