Formulary Exclusion of Esomeprazole: Impact on Healthcare Costs and Utilization | Page 1
Published Online: August 15, 2013
Berhanu Alemayehu, DrPH; Joseph A. Crawley, MS; Xiongkan Ke, MS; and Marta Illueca, MD
Current healthcare costs are more than $2.5 trillion annually in the United States and are expected to rise by a projected rate of 6.2% annually through 2018.1 To control prescription utilization and expenditures, managed care organizations promote lower-cost medications within a class of pharmacologic therapies or restrict specific higher-cost medications from their formularies.2,3 However, few studies have evaluated the effects formulary changes involving proton pump inhibitors (PPIs) have had on healthcare utilization and costs.
A therapeutic substitution policy was implemented in British Columbia requiring patients with acid-related diseases to switch from their currently prescribed PPI to that with the lowest monthly acquisition cost (rabeprazole).4,5 Initial analysis of data from patients 66 years or older in the provincial drug benefi ts program suggested that the British Columbia therapeutic substitution policy resulted in substantial savings in pharmacy costs during the first 6 months.4 However, a subsequent analysis of data from the entire study population found a significant and preventable increase in net healthcare costs (pharmacy costs, physician services,and hospital services) over approximately 3 years.5 Similarly, findings from 2 other studies showed that formulary restriction of omeprazole led to cost increases for other medical services and increased the risk of negative outcomes in some patients, including more severe symptoms and decreased treatment satisfaction.2,6
Proton pump inhibitors are a commonly prescribed class of medications.7 Similar to other PPIs,8,9 esomeprazole (Nexium) is indicated for gastroesophageal reflux disease (GERD); erosive esophagitis (EE); reduction of the risk of gastric ulcer in patients taking nonsteroidal antiinflammatory drugs (NSAIDs); eradication of Helicobacter pylori in combination with other medications to reduce the risk of duodenal ulcer recurrence; and Zollinger-Ellison syndrome in adults.10 Although medications within the same class often are deemed therapeutically equivalent by a formulary plan, they may not be clinically equivalent in real-world situations. In fact, pharmacologic studies have demonstrated that treatment with esomeprazole can provide more effective acid control11-14 and better maintenance of healing15-17 of EE than treatment with other PPIs.
Esomeprazole was excluded from the United Healthcare formulary for most patients beginning September 1, 2006, and was excluded through United Healthcare beginning January 1, 2007, for all patients who had initially deferred the exclusion. Thereafter, most patients on esomeprazole were required to switch to another PPI if they wanted the prescription cost to be covered by United Healthcare. Patients could continue on esomeprazole only if they were with a subset of formularies thatcontinued to make esomeprazole available in a limited fashion or if they paid the entire cost as an out-of-pocket expense. Findings from a previous analysis evaluating healthcare utilization 6 months after esomeprazole formulary exclusion showed that the costs associated with increased individual patient utilization of healthcare resources surpassed observed prescription cost savings.18 In this study, prescription medication costs and healthcare utilization were assessed in a medical claims database 12 months before and 12 months after the United Healthcare formulary exclusion of esomeprazole.
PATIENTS AND METHODS
Study Design and Patients
This retrospective claims analysis was conducted using a study design that allowed comparison of healthcare utilization and costs during the 12 months before and after formulary exclusion of esomeprazole, and between patients who switched to another PPI and patients who remained on esomeprazole. Healthcare utilization and costs for patients who had claims for esomeprazole and another PPI (mixed cohort) after the formulary exclusion were also compared.
Patients eligible for inclusion in the study were 18 years or older; had 1 or more prescription claims for esomeprazole at an approved dose for EE, GERD, or risk reduction of NSAID-associated gastric ulcer; and had continuous plan eligibilityduring the index period (March 1, 2005, through December 31, 2007; Figure 1). (Current Procedural Terminology, 4th edition codes for procedures specifi c to the upper gastrointestinal [GI] tract are included in eAppendix A, available at www.ajmc.com.) Patients with a GI-related diagnosis code but no claim for esomeprazole were excluded. Patients with a claim for esomeprazole or any other PPI in the pre-exclusion period but no GI diagnosis code and patients with no claim for esomeprazole or any other PPI in the postindex period also were excluded. Additional inclusion criteria included 2 or more prescriptions for esomeprazole (>60 days of supply) during the baseline period, which was defi ned as a sliding 12-month window from March 1, 2005, to August 31, 2006 (Figure 1).
Patients were stratifi ed based on their indication for using esomeprazole, as described previously. Indications for using esomeprazole were determined based on International Classification of Diseases, 9th Revision (ICD-9) codes or prescription claims data: EE (ICD-9 codes 530.10- 530.19), GERD (ICD-9 codes 530.81 and 787.1), and risk reduction of NSAID-associated gastric ulcer (identified by >1 NSAID prescription claim and PPI prescription claim within 6 days of each other; it was assumed that these patients were taking a PPI to reduce the risk of developing NSAID-associated gastric ulcers and not for a preexisting acid-related disorder).18 The types and number of visits, as well as healthcare costs, were calculated per patient per 12 months in the pre-exclusion and postexclusion periods. Data for this study were obtained from health plan enrollmentand medical and pharmacy claims from the Ingenix LabRx database for the period of March 1, 2005, to December 31, 2007.
Healthcare utilization and costs incurred before and after the formulary exclusion of esomeprazole were assessed in patients who switched to another PPI and patients who remained on esomeprazole. Specific outcome measures were (1) total medical services and related costs and (2) upper GI–related healthcare utilization and expenditures.
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