Stable angina patients have low rates of death, high rates of hospitalization

February 3, 2015 – The study, led by Thomas Povsic, MD, PhD, examined data from more than 1,900 patients who underwent cardiac catheterization between 1997 and 2010.

Patients with stable angina have relatively low rates of death, but high rates of hospitalization and resource utilization. This finding from a new study published in the Journal of the American Heart Association could have implications for the future of health care costs in the United States.

The study was conducted by the DCRI’s Thomas Povsic, MD, PhD (pictured); Samuel Broderick, MS; Kevin Anstrom, PhD; Linda Shaw, MS; E. Magnus Ohman, MD; Eric Eisenstein, DBA; Peter Smith, MD; and John Alexander, MD, MHS.

thomas-povsic-newsAs many as 1.8 million Americans suffer from refractory angina, but the clinical characteristics and long-term outcomes of this population are poorly understood. To remedy this, the DCRI researchers conducted an analysis of angina patient data from the Duke Databank for Cardiovascular Disease (DDCD). The DDCD is the largest and oldest institutional cardiovascular database in the world, containing information on more than 200,000 patients.

For this study, the researchers examined data from patients with class II to IV angina who underwent cardiac catheterization between 1997 and 2010 and who remained clinically stable for 60 days. Clinical stability was defined as remaining alive without rehospitalization, heart attack, stroke, or revascularization during the 60‐day period following catheterization. Of the 77,257 patients who underwent cardiac catheterization during this period, 1,908 met the inclusion criteria.

To determine the characteristics that affected the clinical endpoints of death, heart attack, and rehospitalization, the researchers conducted a statistical analysis of 30 baseline characteristics. Associated health care costs were determined by obtaining relevant hospitalization and rehospitalization records.

The researchers found that the 3‐year incidence of death, rehospitalization, and a composite of death, heart attack, stroke, cardiac rehospitalization, and revascularization was 13.0 percent, 43.5 percent, and 52.2 percent, respectively. Age, ejection fraction, body mass index, multivessel coronary artery disease, heart rate, diabetes, diastolic blood pressure, history of coronary artery bypass graft surgery, cigarette smoking, history of congestive heart failure, and race were all found to be predictors of mortality. Multivessel coronary artery disease, ejection fraction less than 45 percent, and history of congestive heart failure increased a patient’s risk of death. Angina class and prior revascularization, however, did not. The researchers found that the total costs associated with rehospitalization over a 3‐year period were $10,185 per patient.

The researchers noted that their findings showed a lower rate of mortality than shown by earlier studies. Newer, more effective treatments for angina might be partially responsible for this difference. They also noted that their cost analysis was probably a conservative estimate of the true cost of angina patients, as their analysis included only costs of cardiovascular hospitalizations, relied on self‐reporting of hospitalization, and did not account for Medicare Part B costs. Further research on resource utilization and patients’ quality of life is needed, they concluded.