Predicting Life Expectancy of Heart Failure Patients

A new statistical heart failure model predicts the life expectancy of heart failure patients by combining therapeutic approaches with a variety of laboratory variables.

Researchers at the University of Washington (Seattle, USA) developed the Seattle heart failure model, which makes use of eight demographic variables, including age and gender, and 11 laboratory variables, such as cholesterol level and white blood cell count. In addition, the model takes into account five common classes of heart failure medications: angiotensin-converting enzyme (ACE) inhibitors, beta blockers, angiotensin-receptor blockers, diuretics, and statins. The model also calculates the survival effects of four common devices used to treat heart failure: biventricular pacemakers, implantable cardio-defibrillators, biventricular implantable cardio-defibrillators, and left ventricular-assist devices.

The model was developed by examining data from 1,125 heart failure patients in the Prospective, Randomized AmlodIpine Survival Evaluation (PRAISE1) study. The model was then prospectively validated among nearly 10,000 additional patients from five other clinical trials, observational studies, or clinical registries. When the investigators compared survival rates predicted by the model to actual survival rates in the five validation cohorts, accuracy ranged from 97% to 99%. The study was published in the March 21, 2006 edition of Circulation.

A heart failure patient treated with only digoxin and diuretic therapy with a 20% annual mortality rate will live about four years on average. However, according to the Seattle Heart Failure Model, if you add an ACE inhibitor the patient will live five years, and if you add an ACE inhibitor and a beta blocker the patient will live six and a half years, said lead author Wayne C. Levy, M.D., of the University of Washington. If you use an ACE inhibitor, beta blocker, and an aldosterone blocker, the patient makes it to eight years, or double the original life span. And if you add an implantable cardioverter defibrillator you would make it to nine and a half years.



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