The Effect of Formulary Restrictions on Patient and Payer Outcomes: A Systematic Literature Review.

BACKGROUND Formulary restrictions are implemented to reduce pharmacy costs and ensure appropriate use of pharmaceutical products. As adoption of formulary restrictions increases with rising pharmacy costs, there is a need to better understand the potential effect of formulary restrictions on patient and payer outcomes. OBJECTIVE To conduct a systematic literature review that assesses the effect of formulary restrictions on the following outcomes: medication adherence, clinical outcomes, treatment satisfaction, drug utilization, health care resource utilization, and economic outcomes. METHODS Studies published in 2005 or later were identified from the MEDLINE, Embase, and Cochrane databases and the National Health Service Economic Evaluation Database, using 2 sets of search terms. A total of 17 formulary restriction terms (e.g., step therapy [ST] and prior authorization [PA]) and 55 outcome terms were included, resulting in 935 unique search term combinations. Two reviewers independently conducted analyses of the titles, abstracts, and full-text articles. The search was limited to English-language articles that evaluated the effect of ST and/or PA placed by U.S. third-party payers on the following outcomes: patient outcomes (medication adherence, clinical outcomes, and treatment satisfaction) and payer outcomes (drug utilization, health care resource utilization, and economic outcomes). RESULTS Of 2,321 reviewed articles, 59 articles met the study inclusion criteria. The included studies assessed the effect of ST (n = 18), PA (n = 35), or both (n = 6) on medication adherence (n = 14), clinical outcomes (n = 12), treatment satisfaction (n = 2), drug utilization (n = 39), health care resource utilization (n = 18), and economic outcomes (n = 42). The 59 articles measured 164 outcomes across the patient, health care resource utilization, and economic outcome categories of interest. Of the total number of outcomes, 50.6% (n = 83) were negative in direction or were unfavorable, whereas 40.2% (n = 66) were positive in direction or were favorable, when the perspectives of patients and payers were considered. Of the total number of drug utilization outcomes reported (n = 46), the majority showed lower drug utilization (> 90%). However, in some of the articles, pharmacy cost savings resulting from lower drug utilization appeared to be offset by increased medical costs. CONCLUSIONS Formulary coverage decisions may have unintended consequences on patient and payer outcomes despite lower drug utilization and pharmacy cost savings; therefore, careful evaluation of restrictions before policy implementation and continued reevaluation after implementation is warranted. DISCLOSURES This study was funded by Novartis Pharmaceuticals. Park and Ko are employed by Novartis Pharmaceuticals in East Hanover, New Jersey, and Ko holds stock in Novartis. Raza, George, and Agrawal are employed by Novartis Healthcare in Hyderabad, India. Study concept and design were contributed primarily by Park and Ko, along with the other authors. Raza, George, and Agrawal collected the data, along with Park and Ko. Data interpretation was performed by Agrawal, Raza, George, Park, and Ko. The manuscript was written and revised by Raza, George, and Park, along with Ko and Agrawal. Results from this systematic literature review were presented at the AMCP Annual Meeting 2016; San Francisco, California; April 19-22, 2016.