Association Between Narrow Pharmacy Networks and Medication Adherence

There are narrow or preferred pharmacy networks included within many insurance plans that have in-network pharmacies with reduced prescription prices based on negotiations with the insurance company. These types of insurance plans offer their members reduced cost sharing to incentivize them to use the in-network pharmacies. In 2014, 75% of Medicare Part D (drug coverage plans) and 70% of exchange plan enrollees were in a narrow or preferred network drug plan, so it’s clear that there are many patients who are enrolled in these types of insurance plans. Some professionals have expressed concern that narrow or preferred networks adversely affect medication adherence due to the fact that they might be hard for patients to access based on location. On the flip side, some believe that these types of networks are good for medication adherence because they encourage (and in some cases practically force) members to establish a pharmacy “home” where pharmacists can better support adherence and coordinated care.

The purpose of this study was to assess how narrow pharmacy networks effect plan members’ medication adherence. This study also looked at whether insurancd plans that implemented narrow networks and those that did not were different in the following 2 subgroups: plans with and plans without 90-day prescription programs. These subgroups were included because 90-day prescription programs have shown to be a positive impact on medication adherence.

Data was collected from January 1, 2012, through December 31, 2013, and each subject was studied for only one of the two years from Januray to December. Plans that implemented narrow networks in 2013 were considered intervention plans, while those that implemented them in 2014 were considered control plans. For all plans, CVS/Caremark was the pharmacy benefits manager. The main factors assessed were the differences in members’ medication-possession ratio (MPR) before and after network implementation separately for statins, antihypertensive medications, oral antidiabetic medications, and antidepressant medications. The MPR was defined as the days’ supply from the first through last times that the prescription was filled divided by the days between the first fill date and December 31 of that year. Two narrow network plans (having 67,906 members total) and 3 non-network plans (having 149,989 members total) were included in this study.

The results of the study were that individuals enrolled in narrow network plans had greater increases in MPR than individuals enrolled in non-network plans. In addition, it was found that the difference in MPR improvements before and after network implementation between network plans and non-network plans was greater for plans that had 90-day programs already in place.

This results of this study are really interesting to me because they show how outside factors can influence how patients take their medications. In this case, the outside factor is one’s insurance plan, and insurance definitely plays an important role in access to medications because it can essentially determine whether a person can afford their medications or not. It bothers me that some people miss out on lower prescription prices simply because they are not in narrow of preferred pharmacy network insurance plans, and I do not like that a person’s insurance plan can be a factor in the affordability of medications which can ultimately influence medication adherence. It is important that pharmacists understand how different insurance plans work so we can help our patients afford their medications in order to help them be adherent in sticking to their medication regimen.

My question posed to colleagues: What do you think about the results of this study? Are there ways in which pharmacists can help patients who are not in narrow or preferred networks afford their medications and also stay adherent?

Polinski, JM, Matlin, OS, Sullivan, C, et al. Association Between Narrow Pharmacy Networks and Medication Adherence. JAMA Intern Med. 2015;1850-1853.

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