Mail-Order Pharmacies Potentially Linked to Higher Medication Adherence

Current data show higher medical adherence by patients who use mail-order pharmacies compared to those who use retail pharmacies, but more research is needed to confirm a causal association between medication adherence and use of mail-order pharmacies.

This is the conclusion of a recent systematic review conducted by investigators at Virginia Commonwealth University to assess whether patient medication adherence is related to how the medications are dispensed.  The review included 15 articles that pertained to retail and mail-order pharmacies and medication adherence collected from a literature search of three databases (MEDLINE, Cumulative Index to Nursing and Allied Health Literature [CINAHL], and International Pharmaceutical Abstracts [IPA]. Following identification of various factors for each study (ie, days supply, patients’ out-of-pocket costs, prior adherence behavior, therapeutic class, measure of adherence, limitation, and results), the studies were then categorized by disease state.

The investigators found that most of the studies found that patients who used mail-order pharmacies were more likely to adhere to their medications. Of the 15 studies, 14 supported higher medication adherence through mail-order pharmacies.

According to the investigators, the reason for the difference between the two dispensing channels and adherence seems, in part, to be due to selection bias. Compared to patients who used retail pharmacies, those who used mail-order pharmacies were more likely to have higher prior adherence behavior, days supply of medicines received, socioeconomic status, and offered financial incentives to use mail order.

However, the investigators caution that more research is needed to conclusively determine a causal relationship between use of mail-order pharmacies and higher medication adherence. They point out that only a few of the studies statistically controlled for relevant variables (ie, prior adherence behavior, days supply of medicines received, socioeconomic status, and financial incentives), and despite showing that mail-order pharmacies were associated with higher adherence, the size of the differences were small.

“These differences, differing definitions of mail-order usage, and the fact that patients with substantial use of both retail and mail-order settings had lower adherence than those using primarily retail pharmacies provide some reasons to doubt that mail-order pharmacy offers an inherent adherence advantage,”  the study investigators concluded. —Mary Beth Nierengarten