Predictors of β-blocker initiation after myocardial infarction in patients with type 2 diabetes: A retrospective study of a privately insured US population

Background: Beta-blockers remain important for secondary prevention after myocardial infarction (MI). Despite clinical guideline recommendations, underutilization of this pharmacotherapy continues in patients with type 2 diabetes (T2DM) compared to the general post-MI population. Objective: This study aimed to (1) quantify the proportion of T2DM patients utilizing β-blocker therapy within 30 days of hospital discharge after MI and (2) identify clinical and demographic characteristics predicting initiation of β-blocker therapy. Methods: A retrospective cohort of US employed, commercially insured individuals was assembled using de-identified enrollment files, medical claims, and pharmacy claims from 2007 to 2009. Inclusion criteria were the following: (1) type 2 diabetes, (2) ≥18 years old, (3) continuous eligibility, (4) MI. Multivariable logistic regression with adjusted odds ratios (OR_adj) using manual backward elimination was used to identify predictors of β-blocker initiation within 30 days of discharge from index hospitalization. Results: Of 341 T2DM patients, 167 (49.0%) were new users and 174 (51.0%) were nonusers of β-blockers within 30 days of post-MI hospital discharge. Patients on a calcium channel blocker (OR_adj 2.63) and patients taking 1 to 5 medications (OR_adj 3.59) were more likely to initiate β-blockers post-MI. Patients with heart failure (OR_adj 0.45) or an arrhythmia (OR_adj 0.44) were less likely to initiate β-blockers as well as patients with renal failure not taking a diuretic (OR_adj 0.17). Conclusions: These results confirm previous findings that β-blockers are underutilized in T2DM patients post-MI. Predictors from the regression model can guide future research investigating how this deviation from guidelines is attributed to prescriber versus patient behavior.