Regional Density of Cardiologists and Rates of Mortality for Acute Myocardial Infarction and Heart Failure

Study Questions:

What is the relationship between regional density of cardiologists across the United States and patient risk of 30-day and 1-year mortality after hospitalization for acute myocardial infarction (AMI) and heart failure (HF)?

Methods:

Using Medicare administrative claims data from 2010, the investigators examined the relationship between regional density of cardiologists and risk of death after hospitalization for AMI and HF using hospitalizations for pneumonia as a comparison. They defined density as the number of cardiologists divided by population ages ≥65 years within hospital referral regions, categorized into quintiles. Among 171,126 admissions for AMI, 352,853 admissions for HF, and 343,053 admissions for pneumonia, the authors tested associations between density of cardiologists and 30-day and 1-year mortality for each condition. They used two-level hierarchical logistic regression models that adjusted for characteristics of patients and hospital referral regions.

Results:

Patients hospitalized for AMI (odds ratios [OR], 1.13; 95% confidence interval [CI], 1.06-1.21) and HF (OR, 1.19; 95% CI, 1.12-1.27) in the lowest quintile of density had modestly higher 30-day mortality risk compared with patients in the highest quintile, unlike patients hospitalized for pneumonia (OR, 1.02; 95% CI, 0.96-1.09). Patients hospitalized for AMI (OR, 1.06; 95% CI, 1.00-1.12) and HF (OR, 1.09; 95% CI, 1.04-1.13) in the lowest quintile had slightly higher 1-year mortality risk, unlike patients hospitalized for pneumonia (OR, 1.00; 95% CI, 0.95-1.05).

Conclusions:

The authors concluded that patients hospitalized for AMI and HF in regions with a low density of cardiologists experienced modestly higher 30-day and 1-year mortality risk, unlike patients with pneumonia.

Perspective:

This study found that patients who were hospitalized for AMI and HF in regions with a lower density of cardiologists had modestly higher 30-day and 1-year mortality risk compared with patients hospitalized in regions with higher density. We need a better understanding of the causes of this observed difference in mortality to develop targets for interventions to improve outcomes. It seems that regions with a lower density of cardiologists will need to develop new and innovative approaches to achieve results that are similar to those of higher density regions.

Clinical Topics: Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: Heart Diseases, Odds Ratio, Myocardial Infarction, Pneumonia, Heart Failure, Confidence Intervals, Medicare, Hospitalization, Logistic Models, United States


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