Three-tiered-copayment drug coverage and use of nonsteroidal anti-inflammatory drugs.
BACKGROUND
Previous studies of 3-tier formularies are rare, although the evidence suggests that their cost-sharing structure reduces overall drug spending. However, it is unclear how incentive-based formularies affect the selection of medications with safety advantages, or restrict the access that high-risk populations have to recommended therapies in the higher tiers. This study was designed to determine whether 3-tier formularies influence the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in a population of patients with arthritis.


METHODS
This retrospective study used the 2000 MarketScan Research Database, which contains person-level claims data for employer-sponsored health plans. The sample for this study consisted of 20 868 individuals treated for osteoarthritis or rheumatoid arthritis and using NSAIDs while enrolled in tiered drug plans (n = 32). The likelihood of any use of cyclo-oxygenase (COX-2)-selective inhibitors was determined as a function of tiered drug plan coverage, adjusting for other person-level and plan-level covariates.


RESULTS
Use of COX-2-selective inhibitors decreased (63.0% vs 53.6% vs 41.6%, respectively) and use of generic NSAIDs increased (37.7% vs 40.7% vs 55.7%, respectively) as formularies incorporated 1, 2, and 3 tiers. Enrollees in 3-tier plans with arthritis and serious gastrointestinal comorbidities (odds ratio, 0.51; 95% confidence interval, 0.40-0.66) were significantly less likely to use COX-2-selective inhibitors compared with patients in 1-tier plans.


CONCLUSIONS
Three-tier formularies appear to reduce the use of COX-2-selective inhibitors among all patients with arthritis, even those at risk of experiencing gastrointestinal complications from using nonselective NSAIDs. These findings are among the first to suggest that tiered-copayment drug plans may be influencing the selection of medications beyond generic and branded products.
Briesacher
Becky
B
Division of Geriatric Medicine, University of Massachusetts Medical School, Worcester 01605, USA. Becky.Briesacher@umassmed.edu
Kamal-Bahl
Sachin
S
Hochberg
Marc
M
Orwig
Denise
D
Kahler
Kristijan H
KH
D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000191:economics* / Q000627:therapeutic use; D001168:Arthritis / Q000188:drug therapy* / Q000191:economics / Q000453:epidemiology; D015897:Comorbidity; D017047:Cost Sharing; D016861:Cyclooxygenase Inhibitors / Q000191:economics* / Q000627:therapeutic use; D016568:Drugs, Generic; D005260:Female; D005569:Formularies as Topic; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000209:etiology; D015438:Health Behavior; D006297:Health Services Accessibility; D006801:Humans; D007356:Insurance, Pharmaceutical Services / Q000191:economics*; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care; D012052:Reimbursement, Incentive; D012189:Retrospective Studies; D012306:Risk; D014481:United States / Q000453:epidemiology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D016568:Drugs, Generic