Life-years gained from coronary heart disease mortality reduction in Scotland: prevention or treatment?

Coronary Heart Disease (CHD) death rates have fallen considerably in many countries. We estimated the life-years-gained (LYG) in Scotland between 1975 and 1994 attributable to cardiology treatments, and population reductions in major CHD risk factors, using a previously validated mortality model. This combines published effectiveness data with information on uptake of CHD treatments; risk factor trends; and median survival by age and sex. Compared with 1975, there were 4,536 fewer CHD deaths in 1994, resulting in approximately 48,016 LYG among those aged 45-84 (maximum estimate 53,317; minimum estimate 36,867). Medical and surgical treatments for CHD patients gained approximately 12,025 life-years; the largest contribution coming from pharmacologic secondary prevention. Population reductions in major risk factors (smoking, cholesterol, and blood pressure) accounted for some 35,991 LYG, reductions in smoking accounted for over 50% of this. Modern cardiologic treatments gained many thousands of life-years in Scotland, but modest reductions in risk factors gained almost three times as many life-years.