Secular trends in cardiovascular mortality in Iran, with special reference to Isfahan

There has been a general decline in mortality from cardiovascular diseases (CVDs) in most of the developed countries since the beginning of the 1970s. Still, in recent years developing countries have seen an increasing frequency in CVD mortality. However, mortality rate studies in these populations are scarce. Here we report all-cause and CVD mortality rates for men and women aged 25-74 years over a 16-year period in 24 cities in Iran with special reference to the city of Isfahan.

The study was based on national death records using the ninth international classification of diseases and age standardization was performed using the total population of Iran in 1985 as a standard. Due to limitations in available data, mortality rates for the specific categories of CVD for the whole country could not be provided. The in-hospital death rates following myocardial infarction in coronary care units (CCUs) and cardiology departments in Isfahan hospitals were also assessed. The completed medical records from hospitals or the relatives of decedents were reviewed by physicians certified in internal medicine, cardiology and neurology to assess the reliability of death certificate data regarding CVD by determining the sensitivity and specificity of the death certificates against the standard of the reviewers. The official circulatory diseases proportional mortality ratio continues to rise since 1981 with a steep increase since 1987, constituting 26.6% and 47.3% of all deaths in 1981 and 1995, respectively. Age-adjusted all-cause and CVD mortality data were decreasing since 1981 and increasing since 1990. During those years age-adjusted CVD, stroke and other CVD mortality rates were decreasing in Isfahan with a slight increase in ischaemic heart disease (IHD) death rates in both sexes. Mortality rates based on sex showed a 38% and 24.8% decline in all-cause and CVD mortality in men between 1981 to 1995, and a 35% and 34.9% decline for female mortality rates for the same period, respectively. The in-hospital death rate following myocardial infarction in Isfahan was increasing between 1993 and 1995 with a slight decrease thereafter. The results of death certification assessment showed a specificity of 0.89 and a sensitivity of 0.43 with the positive and negative predictive values of 0.82 and 0.57, respectively.

These data indicate that circulatory diseases remain a serious public health threat in Iran. It suggests the ongoing need for more regular, systematic and innovative surveillance data to improve the capability of measuring, explaining and predicting the disease trend on which the national public health policy depends.