HEALTH EXPECTANCY - AN INDICATOR FOR CHANGE

Study objective - Health expectancy is an increasingly used indicator of population health status. It collapses both mortality and morbidity into a single indicator, and is therefore preferred to the total life expectancy index for populations with low mortality but high morbidit y rates. Three methods of calculation exist: the Sullivan, double decr ement, and multi-state methods. This report aims to describe their rel ative advantages and limitations when used to monitor changes in popul ation health status over time. Design - The differences between the th ree methods are explained. Using a dynamic model of heart disease, the effect of the introduction of thrombolytic treatment on the survival of patients with acute myocardial infarction is calculated. The result ing changes in health expectancy are calculated according to the Sulli van and multi-state methods. Main results - As opposed to the double d ecrement and the multi-state methods, the Sullivan method produces spu rious trends in health expectancy in response to the change in surviva l. Conclusions - Estimates of health expectancy in a dynamic situation can be very misleading when based on the Sullivan method, with its at tractively moderate data requirements. The multi-state method, which r equires longitudinal studies of population health status, is often ind ispensable.