Analysis of nonformulary use of PPIs and excess drug cost in a Veterans Affairs population.

摘要

In the Veterans Affairs (VA) health care system, a formulary-based approach without beneficiary cost-share incentives is used to limit the pharmacy cost of proton pump inhibitors (PPIs). However, the effectiveness of this approach in reducing the cost of PPIs is unknown.To (a) compare cost differences between the formulary PPI (generic omeprazole) and nonformulary PPIs and (b) evaluate reasons for nonformulary PPI use in order to identify opportunities to increase formulary drug use and discourage unnecessary use of nonformulary PPIs.A list of patients with receipt of PPIs from July 1, 2008, through June 30, 2009, was obtained from the Loma Linda VA Healthcare System pharmacy. Subjects with receipt of at least 120 units (capsules or tablets) of any PPI in the study period were considered long-term users. Demographic information was collected. Pharmacy consult records were reviewed to identify reasons for nonformulary use and dosing regimen of the formulary PPI prior to the switch. Cost analysis was done based on the VA contract prices for the drugs at the time of the study.Of 58,605 unique patients seen in this VA health care system in the 12-month period from July 1, 2008, through June 30, 2009, 13,713 (23.4%) received a PPI, and of these, 10,483 (76.4%) received at least 120 PPI units and were defined as long-term users. Of the long-term users, 9,462 (90.3%) were on the formulary PPI generic omeprazole, and 1,021 were nonformulary PPI users. Use of nonformulary PPIs (esomeprazole, pantoprazole, lansoprazole, rabeprazole) accounted for 10.5% of the PPI units and 9.7% of the users but 57.3% of total PPI cost. This pattern resulted in $570,263 in excess spending (i.e., $570,263 would have been saved in the study period if the nonformulary PPI users had used the formulary drug). The most common reason for nonformulary long-term PPI use was persistent symptoms (n=901, 88.2%). Adverse reaction was cited by 111 (10.9%) of nonformulary PPI users, 33.3% (n=37) of whom reported diarrhea. Of those who switched to a nonformulary PPI due to persistent symptoms, 363 (40.3%) were on once-daily dosing prior to the switch; 379 (42.1%) were on twice-daily dosing; and 159 (17.6%) were transfers from other places in which prior dosing information was not available in the hospital pharmacy records.One-year PPI use prevalence was 23% in this VA population, and long-term use prevalence was 18%. Nonformulary PPI use accounted for 10.5% of the PPI units and 9.7% of the users but 57.3% of total PPI drug cost. Opportunities to reduce nonformulary PPI use in order to reduce overall expenditures on PPIs include verification of optimal formulary PPI use, titration to twice-daily dosing, and confirmation of adverse reaction as being attributable to PPI use.