RISK FACTOR AND TREATMENT CONTRIBUTIONS TO THE CORONARY HEART DISEASE MORTALITY DECLINE IN A LOW RISK MEDITERRANEAN POPULATION: SPAIN 1988-2005

BackgroundThe “Mediterranean Paradox” means that low risk countries such as Spain experience substantially less cardiovascular mortality than North Europe or the USA. Can cardiovascular mortality fall further?ObjectiveWe examined the extent to which the decrease in coronary heart disease (CHD) mortality rates in Spain could be explained by changes in cardiovascular risk factors and by the use of medical and surgical treatments in Spain between 1988 and 2005.MethodsWe used a previously validated IMPACT model to combine and analyse data on risk factor trends and uptake and effectiveness of evidence-based cardiac treatments among adult men and women aged 35–74 years. Main data sources included official statistics, longitudinal studies, national surveys, randomised controlled trials and meta-analyses. The difference between observed and expected CHD deaths in 2005 was then partitioned among specific treatments and risk factors. We also performed a sensitivity analysis to quantify the potential effect of parameter uncertainty.ResultsFrom 1988 to 2005, the age-adjusted CHD mortality rate in Spain fell 40% among persons aged 35 to 74 years, resulting in 8528 fewer CHD deaths in 2005. Approximately 48.5% of the fall in CHD deaths was attributed to treatments and 50.6% to changes in risk factors. Among the treatments, the major contributions came from initial therapies for acute coronary syndromes (explaining approximately 13% of the mortality fall), secondary prevention (10%) and heart failure treatments (4%). Decreases in total cholesterol, systolic blood pressure and smoking prevalence explained approximately 37%, 24% and 16% of the mortality fall, respectively. However, important gender differences in risk factors trends were noted: diabetes and obesity increasing in men and smoking prevalence increased in women.ConclusionsApproximately half of the CHD mortality fall in Spain between 1988 and 2005 was attributable to reductions in major risk factors, and almost half to evidence-based therapies. These results are important, both for understanding past trends, and, crucially, for planning future prevention and treatment strategies in low-risk populations.