Date of Award

January 2014

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Harlan M. Krumholz

Second Advisor

Joseph S. Ross

Subject Area(s)

Medicine

Abstract

REGIONAL DENSITY OF CARDIOLOGISTS AND MORTALITY FOR ACUTE MYOCARDIAL INFARCTION AND HEART FAILURE

Vivek T. Kulkarni, Joseph S. Ross, Yongfei Wang, Brahmajee K. Nallamothu, John A. Spertus, Sharon-Lise T. Normand, Frederick A. Masoudi, and Harlan M. Krumholz. Section of Cardiology, Department of Internal Medicine, Yale School of Medicine, New Haven, CT.

Cardiologists are distributed unevenly across regions of the United States. It is unknown whether patients in regions with fewer cardiologists have worse outcomes after hospitalization for acute myocardial infarction (AMI) or heart failure than patients in regions with more cardiologists. We hypothesized that patients hospitalized for AMI or heart failure in regions with lower density of cardiologists would have higher mortality than patients in regions with higher density.

Using Medicare administrative claims data from 2010, we examined the relationship between regional density of cardiologists and mortality after hospitalization for AMI and heart failure, using hospitalizations for pneumonia as a comparison. We defined density as the number of cardiologists divided by population aged ≥ 65 years within hospital referral regions, categorized into quintiles. We tested associations between density of cardiologists and 30-day and 1-year risk-standardized mortality for each condition. We used 2-level hierarchical logistic regression models that adjusted for characteristics of patients and hospital referral regions.

Our cohorts consisted of 171,126 admissions for AMI, 352,853 admissions for heart failure, and 343,053 admissions for pneumonia. Patients hospitalized for AMI (odds ratios [OR], 1.13; 95% confidence interval [CI], 1.06-1.21) and heart failure (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 heart failure (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).

Patients hospitalized for AMI and heart failure in regions with lower density of cardiologists experienced modestly higher 30-day and 1-year mortality risk, unlike patients with pneumonia. These findings suggest that there is a relationship between regional density of cardiologists and mortality for AMI and heart failure, which is concentrated in the early period after these acute events.

Comments

This is an Open Access Thesis.

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