The impact of formulary drug exclusion policies on patients and healthcare costs.

Objectives: In an attempt to increase the efficiency of their drug benefit policies, insurers are increasingly excluding drugs from their formularies that they deem to be of low value. Our objective was to identify and review empirical evaluations of drug exclusion policies and examine how they affected patients and healthcare costs.
Study Design: Literature review.
Methods: We performed a literature search to identify empirical studies that evaluated drug exclusion policies. We reviewed each study to determine how the policy impacted patients (ie, if disease control or frequency, or severity of symptoms, were affected) and if healthcare costs (eg, drug expenditures and costs associated with physician office visits, hospitalizations, laboratory tests) changed.
Results: We included 26 studies pertaining to 27 drug exclusion policies. Twenty studies reported the impact of 21 drug exclusion policies on patients: 6 (28.6%) policies were reported to have had a positive impact, 6 (28.6%) to have had a negative impact, and 9 (42.8%) to not have impacted patients. Eighteen studies reported the impact of 19 drug exclusion policies on overall healthcare costs: 14 (73.7%) policies were reported to have reduced costs, 1 (5.3%) to have had a neutral impact on costs, and 4 (21.1%) to have increased costs.
Conclusions: Although there were important exceptions, most studies found that drug exclusion policies reduced costs and did not negatively impact patients.