Long-term adherence to evidence based secondary prevention therapies after acute myocardial infarction.
BACKGROUND
After acute myocardial infarction (AMI), treatment with beta-blockers and angiotensin-converting enzyme inhibitors (ACEI) is widely recognized as crucial to reduce risk of a subsequent AMI. However, many patients fail to consistently remain on these treatments over time, and long-term adherence has not been well described.


OBJECTIVE
To examine the duration of treatment with beta-blockers and ACEI within the 24 months after an AMI.


METHODS
A retrospective, observational study using medical and pharmacy claims from a large health plan operating in the Northeastern United States.


METHODS
Enrollees with an inpatient claim for AMI who initiated beta-blocker (N = 499) or ACEI (N = 526) therapy.


METHODS
Time from initiation to discontinuation was measured with pharmacy refill records. Associations between therapy discontinuation and potential predictors were estimated using a Cox proportional hazards model.


RESULTS
ACEI discontinuation rates were high: 7% stopped within 1 month, 22% at 6 months, 32% at 1 year and 50% at 2 years. Overall discontinuation rates for beta-blockers were similar, but predictors of discontinuation differed for the two treatment types. For beta-blockers, the risk of discontinuation was highest among males and those from low-income neighborhoods; patients with comorbid hypertension and peripheral vascular disease were less likely to discontinue therapy. These factors were not associated with ACEI discontinuation.


CONCLUSIONS
Many patients initiating evidence-based secondary prevention therapies after an AMI fail to consistently remain on these treatments. Adherence is a priority area for development of better-quality measures and quality-improvement interventions. Barriers to beta-blocker adherence for low-income populations need particular attention.
Akincigil
Ayse
A
School of Social Work, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA. aakinci@rci.rutgers.edu
Bowblis
John R
JR
Levin
Carrie
C
Jan
Saira
S
Patel
Minalkumar
M
Crystal
Stephen
S
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D006279:Health Maintenance Organizations; D006801:Humans; D007349:Insurance, Health, Reimbursement; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000534:rehabilitation*; D010349:Patient Compliance; D012189:Retrospective Studies; D055502:Secondary Prevention
D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors