title: Effect of switching to a high-deductible health plan on use of chronic medications.
abstract: OBJECTIVE
  To examine whether high-deductible health plans (HDHPs) that exempt prescription drugs from full cost sharing preserve medication use for major chronic illness, compared with traditional HMOs with similar drug cost sharing.
  
  
  METHODS
  We examined 2001-2008 pharmacy claims data of 3,348 continuously enrolled adults in a Massachusetts health plan for 9 months before and 24 months after an employer-mandated switch from a traditional HMO plan to a HDHP, compared with 20,534 contemporaneous matched HMO members. Both study groups faced similar three-tiered drug copayments. We calculated daily medication availability for all prescription drugs and four chronic medication classes: hypoglycemics, lipid-lowering agents, antihypertensives, and chronic obstructive pulmonary disease (COPD)/asthma controllers.
  
  
  METHODS
  Interrupted time-series with comparison group study design examining monthly level and trend changes in prescription drug utilization.
  
  
  RESULTS
  The HDHP and control groups had comparable changes in the level and trend of all drugs after the index date; we detected similar patterns in the use of lipid-lowering agents, antihypertensives, and COPD/asthma controllers. Some evidence suggested a small relative decline in hypoglycemic use among diabetic patients in HDHPs.
  
  
  CONCLUSIONS
  Switching to an HDHP that included modest drug copayments did not change medication availability or reduce use of essential medications for three common chronic illnesses.
authors.affiliation: Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, 133 Brookline Avenue, 6th Floor, Boston, MA 02215, USA. skreiss@fas.harvard.edu
authors.forename: Sheila K
authors.initials: SK
authors.lastname: Reiss
authors.forename: Dennis
authors.initials: D
authors.lastname: Ross-Degnan
authors.forename: Fang
authors.initials: F
authors.lastname: Zhang
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Soumerai
authors.forename: Alan M
authors.initials: AM
authors.lastname: Zaslavsky
authors.forename: J Frank
authors.initials: JF
authors.lastname: Wharam
mesh_terms: D000328:Adult; D001249:Asthma / Q000188:drug therapy; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D017047:Cost Sharing / Q000191:economics; D003669:Deductibles and Coinsurance / Q000191:economics*; D003920:Diabetes Mellitus / Q000188:drug therapy; D005260:Female; D006279:Health Maintenance Organizations / Q000191:economics; D006297:Health Services Accessibility; D006302:Health Services Research; D006801:Humans; D006949:Hyperlipidemias / Q000188:drug therapy; D006973:Hypertension / Q000188:drug therapy; D007345:Insurance Claim Review; D007356:Insurance, Pharmaceutical Services / Q000191:economics*; D008297:Male; D008404:Massachusetts; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy