HealthDay News — The effects of trials to improve medication adherence are inconsistent, with few high-quality studies demonstrating improvement in both adherence and clinical outcome, results of a study published in The Cochrane Library indicate.

“People who are prescribed self administered medications typically take only about half their prescribed doses,” explained Robby Nieuwlaat, PhD, of McMaster University in Hamilton, Canada, and colleagues.

“Efforts to assist patients with adherence to medications might improve the benefits of prescribed medications.”

To examine the effects of interventions intended to enhance patient adherence to prescribed medications for medical conditions, the investigators conducted a systematic review of 182 randomized controlled trials.

Due to considerable heterogeneity in terms of medical conditions, patient population, intervention, measures of adherence, and clinical outcomes, the scientists conducted a qualities analysis.

Of the trials, 17 had the lowest risk of bias for study design features and their primary clinical outcome. The trials at lowest risk of bias tended to involve complex interventions with multiple components, including support from family, peers, and health clinicians such as pharmacists, who often delivered education, counseling, and/or daily treatment support.

Improvements in both medication adherence and clinical outcomes were reported by only five of these trials, and there were no common intervention characteristics. There were no large improvements in adherence or clinical outcomes, even with the most effective interventions.

“We need more advanced methods for researching ways to improve medicine adherence, including better interventions, better ways of measuring adherence, and studies that include sufficient patients to draw conclusions on clinically important effects,” concluded the researchers.


  1. Nieuwlaat R et al. The Cochrane Library. 2014; doi: 10.1002/14651858.CD000011.pub4


One author disclosed financial ties to Boehringer Ingelheim.