High Generic Drug Prices and Market Competition

• DOI: 10.7326/m16-1432
• Publication Date: 2017-07-03T22:32:14Z
• Authors: Chintan V. Dave; Aaron S. Kesselheim; Erin R. Fox; Peihua Qiu; Abraham Hartzema
• Keywords: Drug prices

Prices for some generic drugs have increased in recent years, adversely affecting patients who rely on them.To determine the association between market competition levels and change drug prices United States.Retrospective cohort study.Prescription claims from commercial health plans 2008 2013.The 5.5 years of data were divided into 11 study periods 6 months each. The Herfindahl-Hirschman Index (HHI)-calculated by summing squares individual manufacturers' shares, with higher values indicating a less competitive market-and average estimated each period. HHI value baseline period (first half 2008) was modeled as fixed covariate. Models price changes over time level competition, adjusting shortages, size, dosage forms.From 1.08 billion prescription claims, 1120 identified. After adjustment, quadropoly (HHI 2500, relatively high competition), duopoly 5000), near-monopoly 8000), monopoly 10 000) associated -31.7% (95% CI, -34.4% to -28.9%), -11.8% (CI, -18.6% -4.4%), 20.1% 5.5% 36.6%), 47.4% 25.4% 73.2%), respectively, period.Study findings may not be generalizable that became after 2008.Market prices. Such measurements helpful identifying older at risk future.None.