Changes in Myocardial Infarction Guideline Adherence as a Function of Patient Risk: An End to Paradoxical Care?

Abstract

The goals of this analysis were to determine: 1) whether guideline-based care during hospitalization for a myocardial infarction (MI) varied as a function of patients' baseline risk; and 2) whether temporal improvements in guideline adherence occurred in all risk groups. Guideline-based care of patients with MI improves outcomes, especially among those at higher risk. Previous studies suggest that this group is paradoxically less likely to receive guideline-based care (risk-treatment mismatch). A total of 112,848 patients with MI were enrolled at 279 hospitals participating in Get With The Guidelines-Coronary Artery Disease (GWTG-CAD) between August 2000 and December 2008. We developed and validated an in-hospital mortality model (C-statistic: 0.75) to stratify patients into risk tertiles: low (0% to 3%), intermediate (3% to 6.5%), and high (>6.5%). Use of guideline-based care and temporal trends were examined. High-risk patients were significantly less likely to receive aspirin, beta-blockers, angiotensin-converting inhibitors/angiotensin receptor blockers, statins, diabetic treatment, smoking cessation advice, or cardiac rehabilitation referral at discharge compared with those at lower risk (all p < 0.0001). However, use of guideline-recommended therapies increased significantly in all risk groups per year (low-risk odds ratio: 1.33 [95% confidence interval (CI): 1.22 to 1.45]; intermediate-risk odds ratio: 1.30 [95% CI: 1.21 to 1.38]; and high-risk odds ratio: 1.30 [95% confidence interval: 1.23 to 1.37]). Also, there was a narrowing in the guideline adherence gap between low- and high-risk patients over time (p = 0.0002). Although adherence to guideline-based care remains paradoxically lower in those MI patients at higher risk of mortality and most likely to benefit from treatment, care is improving for eligible patients within all risk categories, and the gaps between low- and high-risk groups seem to be narrowing.