Electrocardiographic QT Interval Prolongation and Risk of Primary Cardiac Arrest in Diabetic Patients
- Eric A. Whitsel, MD, MPH12,
- Edward J. Boyko, MD, MPH34,
- Pentti M. Rautaharju, MD, PHD5,
- Trivellore E. Raghunathan, PHD6,
- Danyu Lin, PHD7,
- Rachel M. Pearce, MS3,
- Sheila A. Weinmann, PHD8 and
- David S. Siscovick, MD, MPH39
- 1Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina
- 2Department of Medicine, University of North Carolina, Chapel Hill, North Carolina
- 3Department of Medicine, University of Washington, Seattle, Washington
- 4Epidemiologic Research and Information Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
- 5Department of Public Health Sciences, Wake Forest University, Winston-Salem, North Carolina
- 6Department of Biostatistics, University of Michigan, Ann Arbor, Michigan
- 7Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina
- 8Kaiser Permanente, Portland, Oregon
- 9Department of Epidemiology, University of Washington, Seattle, Washington
- Address correspondencereprint requests to Eric A. Whitsel, Department of Epidemiology, Cardiovascular Disease Program, Bank of America Center, Suite 306, 137 East Franklin St., Chapel Hill, NC 27514. E-mail: ewhitsel{at}email.unc.edu
Sudden cardiac death, also known as primary cardiac arrest (PCA), is a major cause of mortality among diabetic patients and typically occurs in the setting of coronary heart disease. Because it can occur as the first clinical manifestation of coronary heart disease, identifying diabetic patients at risk of PCA remains challenging. Interrelated sequelae of diabetes, including QT prolongation and autonomic failure (1, 2), have been repeatedly implicated in the pathophysiology of PCA (3–6). However, it remains unknown whether the QT interval on a 12-lead electrocardiogram (ECG) has potential utility in risk stratification of diabetic patients without prior physician-diagnosed heart disease for PCA (7–12).
RESEARCH DESIGN AND METHODS
We therefore conducted a case-control study of PCA in a large prepaid health plan, Group Health Cooperative of Puget Sound. We included patients age 18–79 years who were enrolled for ≥1 year or had four or more clinic visits in the prior year, had physician-diagnosed diabetes noted in their ambulatory care medical record or were treated with oral hypoglycemics or insulin, and had an ECG recorded before their index date (see below). We excluded enrollees with prior physician-diagnosed heart disease (Table 1).
Patients were diabetic enrollees who experienced out-of-hospital PCA (a sudden, pulseless condition without a known noncardiac cause) between …
