New adherence study: 90-day home delivery beats 90-day retail


Posted May 22nd, 2015


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Lower medication adherence is a major cause of poor health outcomes and increased overall health care costs, linked to between $100 - $300 billion in unnecessary medical spending in the US.1 That’s up to 10% of the nation’s total health care bill.1

Meanwhile, higher adherence rates have been associated with lower health care costs and better health care outcomes. For example, one study found that patients with diabetes, hypertension or high cholesterol who also had high medication adherence (≥80%) experienced fewer hospitalizations and had lower health care costs compared to patients who were not as adherent to their medication.2

In short, making sure that patients receive their medicines, use their medicines as directed and for as long as directed are critical steps in managing chronic diseases.1

How OptumRx can help

Several studies have indicated that patients who use home delivery pharmacy are more likely to have better adherence compared with patients who obtained medication refills at local retail pharmacies.4, 5 It is thought that the added convenience of longer prescription durations via mail is one reason why patients find it easier to stay compliant with their medications.

More recently, some benefit plans have begun to allow patients to fill a 90- day supply of maintenance medications at retail pharmacies. This raises the question: Is it possible that the new, longer refill periods would bring retail customers up to the same or similar adherence standards as home delivery? But few studies have compared the impact of 90-day supply fills from both channels on medication adherence.6

New research

OptumRx recently presented the results of a study designed to compare medication adherence among patients who filled 90-day supplies of maintenance medications through OptumRx home delivery pharmacies versus the same 90-day supply through retail pharmacies.7Using our large database of pharmacy claims data, we conducted a retrospective study on patients who were being treated with one of five common therapeutic medication classes: anti-diabetics, beta-blockers, calcium channel blockers, other anti-hypertensives and statins.

In order to evaluate who remained adherent, we relied on the industry-standard measurement called Proportion of Days Covered, or PDC, as defined by the Pharmacy Quality Alliance.8 A simple way to describe PDC is that it defines how adherent a patient is to their prescription medications based on how often they refill them during the time period being measured.8

For the medication classes evaluated in this study, a patient who has a PDC of at least 80% is considered to be adherent.1


The study findings suggest that among the patients who newly started these chronic medications, using home delivery pharmacy could lead to improved medication adherence. Patients using OptumRx home delivery to fill 90-day supply prescriptions demonstrated better adherence to maintenance medications than patients filling 90-day supplies at retail pharmacies.

We can see the effect of home delivery versus retail in two ways. First, patients filling 90-day supply through home delivery demonstrated a significantly higher PDC for all 5 medication classes. This means that, for each drug class, home delivery patients were regularly filling their prescriptions at a higher rate than their retail counterparts – even though the length of the prescriptions was the same.


As shown below, what is even more important is that more patients in the home delivery pharmacy group were adherent (at least 80% PDC) with their medications, compared to the retail pharmacy group. For the medications we studied, the home delivery group had +13.4% higher adherence across all categories. Users of statins were 15% higher, anti-diabetic drug users showed 15.6% higher adherence, while calcium channel blocker users were also over 15% more adherent. All differences noted are statistically significant.



This study shows that patients using OptumRx home delivery had better adherence to maintenance medications than patients filling 90-day supply at retail pharmacies.

For OptumRx, this research helps place home delivery squarely within our roster of adherence-promoting capabilities, including text messaging and refill reminders and our monitoring and outreach programs. It is a vital component of our overall value proposition.

Home delivery is one of the most important services that we and our customers rely on to keep health care more affordable for everyone. It reaffirms our belief that the best way to manage pharmacy costs – and total health care costs – is to help individuals make better health care decisions and live healthier lives.


  1. Risk Management and Healthcare Policy. Adherence and health care costs. Feb. 20. 2014. Accessed at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3934668/ on 04.21.2015.
  2. Medical Care.  Impact of Medication Adherence on Hospitalization Risk and Healthcare Cost. Michael C. Sokol, MD, MS, et al. Volume 43, Number 6, June 2005. Accessed at: http://www.vitality.net/docs/managedcare_article.pdf on 04.21.2015.
  3. DEPARTMENT OF HEALTH & HUMAN SERVICES. Centers for Medicare & Medicaid Services. Memo: Enhancements to Medicare Part D Patient Safety Reports and Website. Sept. 30, 2010. Accessed at: http://www.cms.gov/Medicare/Prescription-Drug-Coverage/PrescriptionDrugCovContra/downloads/2010PtSafetyReportEnhan_memo_093010.pdf on 04.21.2015.
  4. Journal of Medical Economics. Mail-order pharmacy use and medication adherence among Medicare Part D beneficiaries with diabetes.  Zhang L, Zakharyan A, Stockl KM, et al. 2011, Vol. 14, No. 5 , Pages 562-567.
  5. American Journal of Managed Care.  Mail-order pharmacy use and adherence to diabetes-related medications. Duru OK, Schmittdiel JA, Dyer WT, et al.  January 14, 2010. Accessed at: http://www.ajmc.com/publications/issue/2010/2010-01-vol16-n01/AJMC_2010Jan_Duru_33to40/ on 04.21.2015.
  6. American Journal of Managed Care. Medication adherence for 90-day quantities of medication dispensed through retail and mail order pharmacies. Khandelwal N, Duncan I, Rubinstein E, et al. November 7, 2011. Accessed at: http://www.ajmc.com/articles/Medication-Adherence-for-90-Day-Quantities-of-Medication-Dispensed-Through-Retail-and-Mail-Order-Pharmacies on 04.21.2015.
  7. Medication Adherence among Mail-order Pharmacy Users versus Retail Pharmacy Users with 90-Day Supply Prescription Fills. Lihua Zhang, MD, PhD, et al. Presented at the Academy of Managed Care Pharmacy 2015 Annual Meeting, San Diego, CA – April 7-10, 2015.
  8. Pharmacy Quality Alliance. Proportion of Days Covered (PDC) as a Preferred Method of Measuring Medication Adherence.  Accessed at: http://pqaalliance.org/resources/adherence.asp on 04.21.2015.
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This article is directed solely to its intended audience about important developments affecting the pharmacy benefits business. It is not intended to promote the use of any drug mentioned in the article and neither the author nor OptumRx has accepted any form of compensation for the preparation or distribution of this article.