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Mail-Order Versus Local Pharmacies on Adherence: Study Methods Make for Unfair Comparison

The American Journal of Managed CareMarch 2010
Volume 16
Issue 3

To the Editor:

Dr Duru and colleagues1 used prescription claims from mail-order pharmacies and local pharmacies to compare medication possession rates across both sites. Based on this analysis, they concluded that patients using mail-order pharmacies had higher adherence to antiglycemic, antihypertensive, and lipid-lowering medications than patients using local pharmacies.

The authors neglect the fact that mail-order pharmacies typically enroll patients in automatic refill programs in order to compensate for the 10- to 14-day advance notice needed to fill prescriptions. With these programs, the mail-order pharmacy sends prescriptions automatically to patients on a regular basis at a predetermined time interval to ensure the patient receives the medication prior to consuming previous supplies. There is no mention of whether the community pharmacies also provided this service. We are assuming that the majority of them did not because this is not a standard of practice.

Given this difference, it is not surprising that an analysis of mail-order pharmacy claims would provide higher medication possession rates. The authors should have considered comparing mail-order pharmacies with community pharmacies that provide automatic refills. That would have been a more appropriate and fair comparison.

Dr Duru and his team also attempted to associate the possession of medication with adherence by providing 3 citations of previous research that found a correlation between the 2 measures. Two of these citations are 22 and 13 years old, respectively, and the third citation represents research that was completed outside of the United States. All 3 citations were based on local pharmacy claims or were conducted prior to the use of automatic refill programs in mail-order pharmacies. In local pharmacies, patients typically request refills when they have consumed most of their medication. This is why medication possession is highly correlated with adherence. We challenge the use of the medication possession concept as a proxy for medication adherence with mail-order pharmacies, which send the medication regardless of how much medication the patient may have remaining.

The authors’ analysis was based on claims for patients who were in a diabetes registry. Despite the limited study population, the conclusion of the research was applied to all patients without discussion of the generalizability of the study population to a larger group.

In their discussion, Dr Duru and colleagues acknowledge that interventions by pharmacists to address adherence have been proven effective. However, they contend that the expansion of responsibilities and the cost of such programs will be barriers to implementation. This has not been the case. In the Medicare Part D program, pharmacists have been providing medication therapy management services since 2006. A recent study estimates that the provision of these services has produced a drug cost savings of $15 to $40 per month.2

It is unfortunate that the above issues limit the usefulness of this research. Instead, it comes off as a thinly veiled attempt to support mail-order pharmacy.

Todd A. Brown, MHP

Nathaniel M. Rickles, PhD

Northeastern University

Boston, MA

Author Disclosures: Mr Brown reports serving as a paid consultant to community pharmacy associations. Dr Rickles reports no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Address correspondence to: Todd A. Brown, MHP, Department of Pharmacy Practice, Northeastern University, 360 Huntington Ave, 206 Mugar Bldg, Boston, MA 02115. E-mail: t.brown@neu.edu.


1. Duru OK, Schmittdiel JA, Dyer WT, et al. Mail-order pharmacy use and adherence to diabetes-related medications. Am J Manag Care. 2010;16(1):33-40.

2. Winston S, Lin Y. Impact on drug cost and use of Medicare part D of medication therapy management services delivered in 2007. J Am Pharm Assoc. 2009;49(6):813-820.


We appreciate the opportunity to confirm the validity of our methods by clarifying 2 incorrect assumptions made by Mr Brown and Dr Rickles. First, the Kaiser Permanente Northern California (KPNC) mail-order pharmacy did not have an automatic refill program in 2006 and 2007 when our data were collected. Although a few KPNC pharmacies have recently launched pilot auto-refill programs, those programs did not overlap with our study window. In our study, mailed medication refills were delivered only after patients initiated refill requests and provided payment. This is no different than the standard of care at community pharmacies, which therefore allows for a fair comparison of adherence between the 2 pharmacy types.

Second, the KPNC diabetes registry has been in existence since 1994 and is designed to be comprehensive rather than to represent a limited subset of patients. Annual, planwide screening protocols examine pharmacy data, laboratory data, hospitalization records, and recorded outpatient diagnoses to add every new case of diabetes to the registry. Comparisons between the registry and self-reported diabetes on member surveys indicate that registry capture is 99% complete. Therefore, our results reflect the broad membership of a health plan rather than a select subgroup.

We stand behind our published findings—specifically, that the likelihood of good adherence to a new diabetes-related medication is greater when refills are obtained through the mail. Although patients can contact the pharmacy call center with questions, better adherence may very well come with a price if inappropriate medication usage is increased for patients who do not interact with community pharmacists. Patients who do not frequent a local pharmacy may be less likely to receive on-site preventive care such as influenza vaccinations. We are initiating analyses to examine these important issues. Still, we believe that the use of mail-order pharmacies may represent a feasible, economical, and sustainable approach to improve adherence to chronic medications for many patients.

Although outcome evaluation studies are ongoing, we agree with Mr Brown and Dr Rickles that interventions in local pharmacies such as medication therapy management programs may be very effective for select populations. These programs target Medicare Part D beneficiaries with multiple chronic health conditions and high pharmacy utilization. The funding and inclusion criteria for these programs were linked to passage of the Medicare drug benefit.1 Unfortunately, the expense and logistics of developing such programs for the millions of other Americans taking chronic medications will be prohibitive in an era of rapidly escalating healthcare costs and deepening budget deficits.

In general, the research on mail-order pharmacies is funded by organizations with presumed agendas of promoting the career interests of community pharmacists or of increasing business opportunities for pharmacy benefit managers. Our work was funded by the Centers for Disease Control and Prevention and the National Institutes of Health, with the sole agenda of improving medication adherence and health outcomes. We believe that there is an urgent need for additional work examining the use of mail-order versus local pharmacies, but this work must be unbiased and focus primarily on the potential benefits and/or harms to patients.

O. Kenrik Duru, MD, MSHS

University of California

Los Angeles, CA

Julie A. Schmittdiel, PhDWendy T. Dyer, MScMelissa M. Parker, MSConnie S. Uratsu, MSJames Chan, PharmDAndrew J. Karter, PhD

Kaiser Permanente Northern California

Oakland, CA

Funding Source: This study was jointly funded by program announcement 04005 from the Centers for Disease Control and Prevention (CDC) (Division of Diabetes Translation) and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the CDC or the NIDDK.

See page 39 of AJMC's January 2010 issue to read the complete disclosure statement.

Author Disclosures: The authors (OKD, JAS, WTD, MMP, CSU, JC, AJK) report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Address correspondence to: O. Kenrik Duru, MD, MSHS, Division of General Internal Medicine, Department of Medicine, The David Geffen School of Medicine at UCLA, University of California, Los Angeles, 911 Broxton Plaza, Los Angeles, CA 90024. E-mail: kduru@mednet.ucla.edu.


1. Barnett MJ, Frank J, Wehring H, et al. Analysis of pharmacist-provided medication therapy management (MTM) services in community pharmacies over 7 years. J Manag Care Pharm. 2009;15(1):18-31.

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