Participation in a Clinical Trial Enhances Adherence and Persistence to Treatment A Retrospective Cohort Study

Hein A. W. van Onzenoort*, Frederique E. Menger, Cees Neef, Willem J. Verberk, Abraham A. Kroon, Peter W. de Leeuw, Paul-Hugo M. van der Kuy

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Poor adherence to treatment is one of the major determinants of an uncontrolled blood pressure. Participation in a clinical trial may increase patient's adherence to treatment. This prompted us to investigate adherence and persistence profiles in patients with hypertension who had participated in a clinical trial, by collecting pharmacy refill data before, during, and after participation in the trial. Pharmacy refill data of 182 patients with hypertension who participated in the Home Versus Office Blood Pressure Measurements: Reduction of Unnecessary Treatment Study between 2001 and 2005 were obtained from 1999 until 2010. Refill adherence to treatment was compared for the periods before, during, and after this trial. Persistence to medication was investigated for the period after termination of the trial. Refill data were available for 22 600 prescriptions. Participation into the trial significantly increased refill adherence, from 90.6% to 95.6% (P90%) were less likely to discontinue treatment compared with nonadherent participants (odds ratio: 0.66 [95% CI: 0.45 to 0.98]). Participation in a clinical trial significantly increases adherence to both trial-related and nontrial-related treatment, suggesting that participants in a trial are more involved with their conditions and treatments. (Hypertension. 2011;58:573-578.)
Original languageEnglish
Pages (from-to)573-578
Issue number4
Publication statusPublished - Oct 2011


  • medication adherence
  • patient compliance
  • medication persistence
  • hypertension
  • refill adherence

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