title: Antihypertensive medication adherence, ambulatory visits, and risk of stroke and death.
abstract: BACKGROUND
  This study seeks to determine whether antihypertensive medication refill adherence, ambulatory visits, and type of antihypertensive medication exposures are associated with decreased stroke and death for community-dwelling hypertensive patients.
  
  
  METHODS
  This retrospective cohort study included all chronic medication-treated hypertensives enrolled in Tennessee's Medicaid program (TennCare) for 3-7 years during the period 1994-2000 (n = 49,479). Health care utilization patterns were evaluated using administrative data linked to vital records during a 2-year run-in period and 1- to 5-year follow-up period. Antihypertensive medication refill adherence was calculated using pharmacy records.
  
  
  RESULTS
  Associations with stroke and death were assessed using Cox proportional hazards modeling. Stroke occurred in 619 patients (1.25%) and death in 2,051 (4.15%). Baseline antihypertensive medication refill adherence was associated with decreased multivariate hazards of stroke [hazard ratio (HR) 0.91; 95% confidence interval (CI), 0.86-0.97 for 15% increase in adherence]. Adherence in the follow-up period was associated with decreased hazards of stroke (HR 0.92; CI 0.87-0.96) and death (HR 0.93; CI 0.90-0.96). Baseline ambulatory visits were associated with decreased death (HR 0.99; CI 0.98-1.00). Four major classes of antihypertensive agents were associated with mortality reduction. Only thiazide-type diuretic use was associated with decreased stroke (HR 0.89; CI 0.85-0.93).
  
  
  CONCLUSIONS
  Ambulatory visits and antihypertensive medication exposures are associated with reduced mortality. Increasing adherence by one pill per week for a once-a-day regimen reduces the hazard of stroke by 8-9% and death by 7%.
authors.affiliation: Division of General Internal Medicine, Department of Medicine, University of Tennessee Health Science Center, 956 Court Avenue, Coleman D222, Memphis, TN 38163, USA. jeb@uthsc.edu
authors.forename: James E
authors.initials: JE
authors.lastname: Bailey
authors.forename: Jim Y
authors.initials: JY
authors.lastname: Wan
authors.forename: Jun
authors.initials: J
authors.lastname: Tang
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Ghani
authors.forename: William C
authors.initials: WC
authors.lastname: Cushman
mesh_terms: D000554:Ambulatory Care Facilities; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D009026:Mortality; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*; D013714:Tennessee / Q000453:epidemiology
chemical_list: D000959:Antihypertensive Agents