Underuse of standard care and outcome of patients with acute myocardial infarction and chronic renal insufficiency

Objectives: To investigate characteristics, management and outcome of patients with acute myocardial infarction (AMI) and chronic renal insufficiency (CRI). Background: Patients with AMI and CRI are considered to be at high risk of complications and death. Physicians may be reluctant to prescribe life-saving medications to patients with concomitant CRI. Methods: We compared clinical characteristics, management and outcome of 1,683 consecutive AMI patients in three categories of renal function: (1) normal renal function (<1.5 mg/dl) (n = 1,559), (2) mild to moderate CRI (1.5- 3.5 mg/dl) (n = 77), and (3) severe CRI (>3.5 mg/dl) (n = 47). Results: CRI patients were older and were more likely to have other co-morbidities such as hypertension, diabetes mellitus, prior AMI, stroke, angina and heart failure. Compared with patients with normal renal function, standard therapy for AMI including thrombolysis, aspirin, angiotensin-converting-enzyme inhibitors, β-blockers and lipid lowering agents was underutilized in CRI patients and these patients were more likely to have in-hospital complications such as heart failure, atrial or ventricular fibrillation, cardiogenic shock, sepsis, worsening of renal function and death within 30 days [odds ratio (OR) = 3.3; 95% confidence interval (CI) = 2.0-4.8]. After adjustment for age and co-morbidities, the association between mild to moderate CRI and 30-days mortality declined, whereas severe CRI remained an independent determinant of mortality (OR = 4.8; 95% CI = 2.0-11.4). Adjustment for aspirin, angiotensin-converting-enzyme inhibitors and β-blocker therapy weakened the association between CRI and death within 30 days after AMI. Conclusions: CRI patients are more likely to experience serious complications and death early after AMI. Underutilization of standard care, particularly β-blocker therapy, contributes to increased mortality risk in these patients.