Impact of changes in pill appearance in the adherence to angiotensin receptor blockers and in the blood pressure levels: a retrospective cohort study

BMJ Open. 2017 Mar 30;7(3):e012586. doi: 10.1136/bmjopen-2016-012586.


Objective: To assess the level of adherence to angiotensin receptor blockers (ARBs) in patients regularly attending a community pharmacy and the influence of a change in patients' adherence to pharmacological treatment.

Design: Retrospective cohort study of a random sample of consecutive patients collecting their medication.

Setting: 40 community pharmacies in Alicante (Southeast Spain).

Participants: 602 consecutive ≥18 years old patients following treatment with ARBs at least 3 previous refills were included.

Main outcome measures: Prevalence of uncontrolled blood pressure (BP) and adherence to prescribed pharmacological treatment (measured through both the Batalla and the Morisky-Green tests). A multivariate Poisson regression model was used to estimate the adjusted risk ratio (RRa) for non-adherence to pharmacological treatment by the presence of a change in patient's adherence and other significant variables.

Results: 161/602 (13.7%) patients presented uncontrolled BP. According to the Morisky test, 410/602 (68.2%) patients were considered adherent to pharmacological treatment and 231/602 (38.4%) patients according to the Batalla test. According to the Morisky-Green test, in the multivariable analysis, patients with a previous change in pill appearance were less likely to be adherent than those patients with no change in their pharmacological treatment (RRa 0.45; CI 95% 0.22 to 0.90; p=0.024). Systolic BP was higher in patients with a change in pill appearance in the previous 3 refills (median BP 142 mm Hg; IQR 136-148) than in those who did not have a change (median BP 127 mm Hg; IQR 118-135; p<0.001).

Conclusions: There was a low percentage of adherence and nearly 15% of uncontrolled BP in patients who regularly collected their medication. Switching between pills of different appearances was associated with lower patient adherence to pharmacological treatment and a higher uncontrolled BP than no change in pharmacological treatment or change only in package but not in pill appearance.

Keywords: adherence; antihypertensive treatment; appearance; community pharmacy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Angiotensin Receptor Antagonists / therapeutic use*
  • Antihypertensive Agents / therapeutic use*
  • Blood Pressure
  • Community Pharmacy Services / statistics & numerical data
  • Drug Packaging
  • Humans
  • Hypertension / drug therapy*
  • Hypertension / psychology
  • Medication Adherence
  • Middle Aged
  • Patient Satisfaction
  • Retrospective Studies
  • Spain
  • Tablets


  • Angiotensin Receptor Antagonists
  • Antihypertensive Agents
  • Tablets