Use of prescription drugs may be the single most common way that diseases are treated, particularly chronic diseases. Ensuring that patients use their medication appropriately therefore assumes great importance. Drug companies obviously have a strong incentive to promote adherence, but payers may as well because effective use of drugs may prevent utilization of more costly care like hospitalizations or ER visits. A new report from the Agency for Healthcare Research and Quality summarizes the Agency’s typical meta-review of evidence on medication adherence intervention effectiveness. (AHRQ Report) After screening, 68 studies were reviewed and almost all of these were randomized trials. Overall they found that many approaches might work to improve adherence, including a number that were relatively inexpensive phone or mail interventions and some that were much more intensive care management approaches.
Less clear was a linkage between improving adherence and improving ultimate outcomes. It is one thing to get people to use the drugs prescribed for them, as prescribed, and it is another to show that such adherence reduces mortality or affects other quality outcomes, or that it will reduce overall costs. On that score, the reviewers said there was little evidence to suggest that the adherence interventions did affect those outcomes. The number of studied interventions varied significantly by disease, with hypertension, depression, asthma and some other chronic conditions having the highest number and also having more consistent evidence that the interventions improved adherence. Some showed improvement on clinical measures like blood pressure, but many did not. Looking at what interventions worked across diseases, it appeared that educational and case management ones had the most consistent evidence of effectiveness. Reducing out-of-pocket expenses appears to have a significant effect on adherence. As mentioned above, however, the reviewers found an almost complete lack of evidence that increasing adherence improves quality or cost outcomes.