title: Adherence patterns among patients treated with fixed-dose combination versus separate antihypertensive agents.
abstract: OBJECTIVE
  Adherence patterns of patients treated with a fixed-dose combination of amlodipine-benazepril versus an angiotensin-converting-enzyme (ACE) inhibitor plus a dihydropyridine calcium-channel blocker (CCB) prescribed as separate drugs were studied.
  
  
  METHODS
  In this retrospective analysis of pharmacy claims from a managed care organization in the northeastern United States, patients who received at least two prescriptions for fixed-dose amlodipine-benazepril (n = 2839) or at least two prescriptions for an ACE inhibitor plus a dihydropyridine CCB (n = 3367) were followed over one year. Adherence, defined as the medication possession ratio (MPR), was calculated based on daily possession of the prescribed drug or drugs over the study period. To estimate the impact of overall drug burden on adherence to antihypertensive therapy, concomitant medication use was calculated as the number of American Hospital Formulary Service (AHFS) drug classes prescribed.
  
  
  RESULTS
  Adherence rates among patients receiving fixed-dose amlodipine-benazepril versus an ACE inhibitor plus a dihydropyridine CCB were 87.9% and 69.2%, respectively (p < 0.0001) over a mean follow-up of 259 and 247 days, respectively. Patients received a mean 4.0 major AHFS drug classes in the amlodipine-benazepril group and 5.2 in the ACE inhibitor plus dihydropyridine CCB group. As the number of concomitant drugs increased, the difference in the MPR between the two treatment groups increased in favor of fixed-dose amlodipine-benazepril.
  
  
  CONCLUSIONS
  Fixed-dose amlodipine-benazepril was associated with higher adherence rates versus an ACE inhibitor plus a dihydropyridine CCB taken as two separate tablets, regardless of the number of concomitant medications prescribed.
authors.affiliation: University of the Sciences in Philadelphia, Philadelphia, PA 19104-4495, USA. c.lyle@usip.edu
authors.forename: Philip P
authors.initials: PP
authors.lastname: Gerbino
authors.forename: Omar
authors.initials: O
authors.lastname: Shoheiber
mesh_terms: D000959:Antihypertensive Agents / Q000008:administration & dosage*; D004338:Drug Combinations; D004359:Drug Therapy, Combination; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000453:epidemiology; D008329:Managed Care Programs; D010349:Patient Compliance; D012189:Retrospective Studies
chemical_list: D000959:Antihypertensive Agents; D004338:Drug Combinations