(49) Post-Myocardial Infarction Guideline-Recommended Therapy Utilization Sankey Diagrams

Publication Number: 380

Background: Guidelines recommend pharmacologic management and participation in outpatient cardiac rehabilitation (CR) to reduce the risk of future cardiovascular events in myocardial infarction (MI) survivors. Prior studies have focused on medication use at a single point of time.

Objectives: The objective of this study is to describe longitudinal and dynamic patterns of guideline-recommended medication (GRM) fills and CR participation within the first 2 years after MI discharge with Sankey diagrams.

Methods: The study population is filtered from a national sample of Medicare beneficiaries aged 66 to 95 years old admitted to the hospital between January 1, 2014 and September 30, 2015 for acute MI (ICD 9CM discharge codes of 410.xx excluding 410.x2). Beneficiaries who survived hospitalization were excluded if their medical history might preclude them from CR participation (i.e. substantial frailty). Prescription claims were reviewed for 25 30-day windows post-discharge fills for 3 GRMs: ACE-inhibitor or ARB (AA), Statin (ST), and Beta-Blocker (BB). Medication use was defined as having at least 21 days’ supply available during a 30-day window. Sankey diagrams of population level trends in the proportion of beneficiaries were produced with 8 GRM combinations and death, stratified by any CR participation during follow-up.

Results: The study population consisted of 25,446 beneficiaries of which 22.8% initiated CR during the study period. The highest proportion had fills for BB-ST and AA-BB-ST combinations at study start (27% and 25%) and study end (18%, 17%), respectively. A higher proportion of CR users had fills for more GRMs than CR non-users. Ten percent of CR users and 16% of CR non-users were in the same GRM category for the entire study period. There was minimal difference between the mean number of oscillations between multiple categories by CR use (5.5 SD:3.8) or no use (5.3 SD:3.9). However, the majority (53%) switched between the same 2-3 GRM groups. Only 14% switched between 5 or more GRM groups post-MI. Lowering the number of GRMs filled was the first change for 66% of beneficiaries. Approximately 10% of the population consistently did not have any GRM fills post-MI regardless of CR use.

Conclusions: Although there were regular transitions between GRM groups, a consistent proportion of beneficiaries had fills within each GRM group post-MI. Improvements in appropriate use of CR and post-MI medications are needed.