TO THE EDITORS:

In the November/December 2012 issue of The American Journal of Pharmacy Benefits, the paper by Murphy et al¹ attempts to measure the level of wastage that is generated when patients change their drug regimen using data from a pharmacy benefit manager. The major contrast is between 30-day and 90-day prescriptions, with the latter thought to have more potential risk of wastage. The authors do a very good job of defining when a patient “switches” to a new medication within the same class or switches dose, and they are careful to look for continuing refills of the initial prescription to avoid counting patients who augment or who are using 2 doses concomitantly to achieve the desired daily dose. The authors combine wastage data from 2 or more therapeutic classes into a single average for the patient, which precludes an analysis of wastage by therapeutic class. The authors also do not use available data to document the patient’s drug use history, which is an important issue in terms of the likelihood that a patient will “switch” therapies, thus causing wastage. Without documentation of the patient’s drug use history, the analysis cannot identify “new” prescriptions (first fill), many of which go through retail first, then switch over to 90-day prescriptions once the patient is stabilized. Patients with any combination of 30-day and 90-day prescriptions are specifically excluded from the analysis.


While many of the above research design decisions are unavoidable, their impact on the interpretation and implications of the study’s results are significant. First, few patients starting a new course of drug therapy are issued an initial prescription for a 90-day supply, but rather switch to a longer prescription following an initial fill for 30 days or, possibly, an initial trial using physician samples, which is unobservable in this data set. Therefore, the more relevant research objective would be to test whether or not pharmacy benefit managers should require patients to switch to a 90-day supply at some point after the initial 30-day fill. This could have been tested by comparing 30-day-only patients with patients switching from 30-day to 90-day prescriptions.


A more troubling issue is that the conclusions derived by the authors are misleading and could result in a reader coming away with the impression that 90-day prescriptions do not risk the wastage of doses. While it is true that “Nearly half of the therapeutic classes examined did not have significantly greater medication wastage for 90-day fills,” a more straightforward summary of the results is that 8 of 14 therapeutic class comparisons found significantly higher wastage in 90-day fills relative to 30-day fills. The percentage increase in wastage in the 90-day prescription group ranged between 32% and 161%. Of the 6 remaining non-significant comparisons, 3 favored 30-day fills and 2 of these achieved a significance level of P <.10. This is hardly a ringing endorsement for the recommendation that payers consider implementing 90-day prescription requirements even for selected therapeutic classes.


Jeffrey S. McCombs, PhD


Department of Clinical Pharmacy and Pharmaceutical Economics and Policy


School of Pharmacy, University of Southern California


The Schaeffer Center for Health Policy and Economics


Los Angeles, CA


Funding Source: None.


Author Disclosure: The author 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: Jeffrey S. McCombs, PhD, Associate Professor, Department of Clinical Pharmacy and Pharmaceutical Economics and Policy, School of Pharmacy, University of Southern California, The Schaeffer Center for Health Policy and Economics, 3335 S Figueroa St, Unit A, Los Angeles, CA 90089-7273. E-mail: jmccombs@usc.edu.


REFERENCE


1. Murphy P, Khandelwal N, Duncan I. Comparing medication wastage by fill quantity and fulfillment channel. Am J Pharm Benefits. 2012;4(6):e166-e171.


IN REPLY:

We appreciate the publication by The American Journal of Pharmacy Benefits of our article examining medication wastage. We also appreciate Dr McCombs’s thoughtful comments on our article. As 90-day assumes a larger market share, mainly due to filling 90-day at retail pharmacies, it is important to understand the relative strengths and weaknesses of different delivery channels. Our objective, therefore, was not to demonstrate that 90-day generated less wastage but that, on balance, this wastage was no greater than that in other more heavily used channels. While we demonstrated differences by therapeutic class, we saw no compelling evidence that a payer who added a 90-day benefit would be subject to significantly increased wastage.


Dr McCombs raises 2 points on our methodology: 1) that we combined therapeutic classes to obtain a single patient average, and 2) that we took no account of a patient’s prescription fill history. However, our study does not combine therapeutic classes and no overall patient average is presented in this manuscript. Furthermore, we only evaluated patients with an established regimen and “exclude patients who were new to therapy,” as described in the methods section. It was not our intention to examine wastage for patients who initially fill a 30-day prescription and then switch to a 90-day one, as would be the case if a payer required patients to switch to 90-day fulfillment after an initial fill.


Our results show that 8 out of 14 therapeutic classes demonstrate lower wastage in the 30-day channel and 6 classes show no significant difference, as stated in the manuscript. We believe that these results taken together with the potential for increased adherence and cost savings when filling 90-day prescriptions indicate that payers have little financial motivation not to consider offering 90-day fills at retail and through mail order as an option together with the traditional 30-day channel.


Patricia Murphy, MPH


Walgreen Co, Deerfield, IL.


Nikhil Khandelwal, PhD


Walgreen Co, Deerfield, IL.


Ian Duncan, FSA, MAAA


Walgreen Co, Deerfield, IL.


Author Affiliations: From Walgreen Co (PM, NK, ID), Deerfield, IL.


Funding Source: Self-funded by Walgreen Co.


Author Disclosures: Drs Murphy, Khandelwal, and Duncan report former employment with Walgreen, Co.


Address correspondence to: Janeen DuChane, PhD, Senior Director, Clinical Outcomes and Analytics, Walgreen Co, 1415 Lake Cook Rd, Deerfield, IL 60015. E-mail: Janeen.DuChane@walgreens.com.