Markku Mähönen

Contribution of trends in survival and coronary-event rates to changes in coronary heart disease mortality : 10-year results from 37 WHO MONICA Project populations

Summary Background The WHO MONICA (monitoring trends and determinants in cardiovascular disease) Project monitored, from the early 1980s, trends over 10 years in coronary heart disease (CHD) across 37 populations in 21 countries. We aimed to validate trends in mortality, partitioning responsibility between changing coronary-event rates and changing survival. Methods Registers identified non-fatal definite myocardial infarction and definite, possible, or unclassifiable coronary deaths in men and women aged 35–64 years, followed up for 28 days in or out of hospital. We calculated rates from population denominators to estimate trends in age-standardised rates and case fatality (percentage of 28-day fatalities=[100-survival percentage]). Findings During 371 population-years, 166 000 events were registered. Official CHD mortality rates, based on death certification, fell (annual changes: men −4·0% [range −10·8 to 3·2]; women −4·0% [-12·7 to 3·0]). By MONICA criteria, CHD mortality rates were higher, but fell less (-2·7% [-8·0 to 4·2] and −2·1% [-8·5 to 4·1]). Changes in non-fatal rates were smaller (-2·1%, [-6·9 to 2·8] and −0·8% [-9·8 to 6·8]). MONICA coronary-event rates (fatal and non-fatal combined) fell more (-2·1% [-6·5 to 2·8] and −1·4% [-6·7 to 2·8]) than case fatality (-0·6% [-4·2 to 3·1] and −0·8% [-4·8 to 2·9]). Contribution to changing CHD mortality varied, but in populations in which mortality decreased, coronary-event rates contributed two thirds and case fatality one third. Interpretation Over the decade studied, the 37 populations in the WHO MONICA Project showed substantial contributions from changes in survival, but the major determinant of decline in CHD mortality is whatever drives changing coronary-event rates.

Estimation of contribution of changes in coronary care to improving survival, event rates, and coronary heart disease mortality across the WHO MONICA Project populations

BACKGROUND The revolution in coronary care in the mid-1980s to mid-1990s corresponded with monitoring of coronary heart disease (CHD) in 31 populations of the WHO MONICA Project. We studied the impact of this revolution on coronary endpoints. METHODS Case fatality, coronary-event rates, and CHD mortality were monitored in men and women aged 35-64 years in two separate 3-4-year periods. In each period, we recorded percentage use of eight treatments: coronary-artery reperfusion before, thrombolytics during, and beta-blockers, antiplatelet drugs, and angiotensin-converting-enzyme (ACE) inhibitors before and during non-fatal myocardial infarction. Values were averaged to produce treatment scores. We correlated changes across populations, and regressed changes in coronary endpoints on changes in treatment scores. FINDINGS Treatment changes correlated positively with each other but inversely with change in coronary endpoints. By regression, for the common average treatment change of 20, case fatality fell by 19% (95% CI 12-26) in men and 16% (5-27) in women; coronary-event rates fell by 25% (16-35) and 23% (7-39); and CHD mortality rates fell by 42% (31-53) and 34% (17-50). The regression model explained an estimated 61% and 41% of variance for men and women in trends for case fatality, 52% and 30% for coronary-event rates, and 72% and 56% for CHD mortality. INTERPRETATION Changes in coronary care and secondary prevention were strongly linked with declining coronary endpoints. Scores and benefits followed a geographical east-to-west gradient. The apparent effects of the treatment might be exaggerated by other changes in economically successful populations, so their specificity needs further assessment.

Relationship of Socioeconomic Status to the Incidence and Prehospital, 28-Day, and 1-Year Mortality Rates of Acute Coronary Events in the FINMONICA Myocardial Infarction Register Study

BACKGROUND Low socioeconomic status (SES) is associated with increased coronary heart disease mortality rates. There are, however, very little data on the relation of SES to the incidence, recurrence, and prognosis of myocardial infarction (MI) events. METHODS AND RESULTS The FINMONICA MI Register recorded detailed information on all MI events among men and women aged 35 to 64 years in 3 areas of Finland during the period of 1983 to 1992. We carried out a record linkage of the MI register data with files of Statistics Finland to obtain information on indicators of SES, such as taxable income and education, for each individual who is registered. In the analyses, income was grouped into 3 categories (low, middle, and high), and education was grouped into 2 categories (basic and secondary or higher). Among men with their first MI event (n=6485), the adjusted incidence rate ratios were 1.67 (95% CI 1.57 to 1.78) and 1.84 (95% CI 1.73 to 1.95) in the low- and middle-income categories compared with the high-income category. For 28-day mortality rates, the corresponding rate ratios were 3.18 (95% CI 2.82 to 3.58) and 2.33 (95% CI 2.03 to 2.68). Significant differentials were observed for prehospital mortality rates, and they remained similar up to 1 year after the MI. Findings among the women were consistent with those among the men. CONCLUSIONS The excess coronary heart disease mortality and morbidity rates among persons with low SES are considerable in Finland. To bring the mortality rates of low- and middle-SES groups down to the level of that of the high-SES group constitutes a major public health challenge.

Socioeconomic Status and Ischemic Stroke The FINMONICA Stroke Register

Background and Purpose— It has been shown that low socioeconomic status is associated with death from stroke. More-detailed data have, however, remained scanty. The purpose of the present study was to examine the association of socioeconomic status with ischemic stroke. Besides mortality, we analyzed the incidence, case-fatality ratio, and prognosis of ischemic stroke events. Methods— Our population-based study included 6903 first stroke events registered by the FINMONICA Stroke Register in 3 areas of Finland during 1983 to 1992. Indicators of socioeconomic status, such as taxable income and education, were obtained by record linkage of the stroke register data with files of Statistics Finland. Results— Incidence, case-fatality ratio, and mortality rates for ischemic stroke were all inversely related to income. Furthermore, 28 days after the onset of symptoms, a greater proportion of patients with low income than of those with high income was still in institutionalized care and/or in need of help for their activities of daily living. Population-attributable risk of the incidence of first ischemic stroke due to low socioeconomic status was 36% for both sexes. For the death from first ischemic stroke, it was 56% for both sexes. Conclusions— Persons with low socioeconomic status have considerable excess rates of morbidity and mortality from ischemic stroke in Finland. A reduction in this excess could markedly decrease the burden of ischemic stroke to the society and thus constitute an important public health improvement.

Trends in Stroke and Coronary Heart Disease in the WHO MONICA Project

Background and Purpose— Coronary heart disease (CHD) and stroke are leading causes of death and disability. Because they share major common risk factors, it would be expected that trends in mortality and incidence of these 2 major cardiovascular diseases would be similar. Methods— Data from the World Health Organization (WHO) Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) Project were used to compare 10-year trends in mortality, event rates, and case fatality from both CHD and stroke. Fifteen populations in the WHO MONICA Project provided data on both CHD (60 763 events) and stroke (10 442 events) in men and women aged 35 to 64 years (23.4 million person-years of observation in total). Results— Trends for the 2 cardiovascular diseases varied within and between populations, and when data from all populations were combined, trends in CHD and stroke mortality differed in men (P =0.001) but not in women, whereas trends in event rates differed significantly in both men and women (P <0.001 and P =0.011, respectively). The differences in trends for CHD and stroke case fatality were not statistically significant in either men or women. In sensitivity analyses, differences in trends in event rates remained statistically significant in men (P <0.001) but not in women. Conclusions— Trends for CHD and stroke mortality rates, event rates, and case fatality differ substantially between and within the study populations.

Are changes in mortality from stroke caused by changes in stroke event rates or case fatality? Results from the WHO MONICA Project

Background and Purpose— Mortality from stroke has been declining over recent decades in most countries, except in Eastern Europe. In this analysis, based on the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease (WHO MONICA) Project, we explored to what extent these trends are due to changes in stroke event rate and to changes in case fatality. Methods— The WHO MONICA Project collected standardized data from 14 populations in 9 countries. All acute strokes occurring in men and women 35 to 64 years of age were included. Registration was carried out between 1982 and 1995, resulting in time spans from 7 to 13 years. Trends in event rates and case fatality were calculated as average annual percentage change. Results— Up to 6-fold differences were observed in stroke mortality. Mortality declined in 8 of 14 populations in men and in 10 of 14 populations in women. An increase in mortality was observed in Eastern Europe. In the populations with a declining trend, about two thirds of the change could be attributed to a decline in case fatality. In populations with increasing mortality, the rise was explained by an increase in case fatality. Conclusions— In most populations, changes in stroke mortality, whether declining or increasing, were principally attributable to changes in case fatality rather than changes in event rates. Whether this was due to changes in the management of stroke or changes in disease severity cannot be established on the basis of these results.

Continuous 15-Year Decrease in Incidence and Mortality of Stroke in Finland. The FINSTROKE Study

Background and Purpose— The purpose of this study was to analyze the incidence and mortality trends in stroke events among persons 25 to 74 years of age in Finland during 1983 to 1997. Methods— The population-based FINSTROKE register recorded 5650 new strokes among persons 25 to 74 years of age in 2 geographical areas of Finland: 2770 in the Kuopio area (east central Finland) and 2880 in Turku (southwestern Finland). Of these, 3065 were men and 2585 were women. Results— The rates of acute stroke events fell during the whole study period in both men and women. In both FINSTROKE areas combined, the average annual decline in the age-standardized incidence of first stroke events was 2.0% (95% confidence interval [CI], −2.8 to −1.2; P <0.001) among men and 1.7% (95% CI, −2.6 to −0.8; P <0.001) among women. The decline in the incidence of ischemic stroke was even steeper, 2.9%/y (95% CI, −4.9 to −1.1; P <0.001) among men and 3.1%/y (95% CI, −5.0 to −1.1; P <0.001) among women, whereas the incidence of intracerebral hemorrhage and subarachnoid hemorrhage did not change. Mortality from all stroke events declined in the FINSTROKE areas by 3.7%/y (95% CI, −5.3 to −2.0; P <0.001) among men and by 4.1%/y (95% CI, −5.9 to −2.4; P <0.001) among women. The 28-day case fatality of all stroke events also tended to decline, but the decline was of borderline statistical significance only (P =0.07 among men, P =0.05 among women). Conclusions— Incidence and mortality of stroke events declined significantly in these 2 register areas in Finland during the 15-year period of 1983 to 1997.

The validity of hospital discharge register data on coronary heart disease in Finland

We studied the validity of the Finnish hospital discharge register data on coronary heart disease (CHD) for the purposes of epidemiologic studies and health services research. The Finnish nationwide hospital discharge register (HDR) was linked with the FINMONICA acute myocardial infarction (AMI) register for the years 1983–1990. The frequency of errors in the HDR was assessed separately. Between 8% and 13% of hospitalized AMI events registered in the AMI Register were not found in the HDR with an ICD code for CHD. Problems with the register linkage and the use of some ICD code other than one of the codes for CHD explained these missing events. The frequency of errors in the personal identification number was about 5% in the early 1980s. After 1986 errors were found only occasionally. The diagnosis recorded in the HDR was the same as that in the discharge sheet in about 95% of hospitalizations. The positive predictive value of the ICD code 410 (AMI), compared with the FINMONICA definite+possible AMI category, was very high and stable, about 90% in all areas and all hospitals, but it sensitivity varied from 50% at local hospitals to 80% at central hospitals. In summary, data on CHD obtained from the Finnish hospital discharge register give, on average, a correct picture on changes in the occurrence of AMI in Finland and can, with necessary caution, be used in epidemiological studies and health services research. However, the classification of individual cases is not standardized in the HDR, but varies over time, between geographical areas and the levels of care. Therefore, these data should not be used without confirmation in studies where correct classification of individual outcomes is of crucial importance, such as follow-up studies and case-control studies.

Do Trends in Population Levels of Blood Pressure and Other Cardiovascular Risk Factors Explain Trends in Stroke Event Rates

Background and Purpose— Previous studies have indicated a reasonably strong relationship between secular trends in classic cardiovascular risk factors and stroke incidence within single populations. To what extent variations in stroke trends between populations can be attributed to differences in classic cardiovascular risk factor trends is unknown. Methods— In the World Health Organization Monitoring of Trends and Determinants in Cardiovascular Disease (WHO MONICA) Project, repeated population surveys of cardiovascular risk factors and continuous monitoring of stroke events have been conducted in 35- to 64-year-old people over a 7- to 13-year period in 15 populations in 9 countries. Stroke trends were compared with trends in individual risk factors and their combinations. A 3- to 4-year time lag between changes in risk factors and change in stroke rates was considered. Results— Population-level trends in systolic blood pressure showed a strong association with stroke event trends in women, but there was no association in men. In women, 38% of the variation in stroke event trends was explained by changes in systolic blood pressure when the 3- to 4-year time lag was taken into account. Combining trends in systolic blood pressure, daily cigarette smoking, serum cholesterol, and body mass index into a risk score explained only a small fraction of the variation in stroke event trends. Conclusions— In this study, it appears that variations in stroke trends between populations can be explained only in part by changes in classic cardiovascular risk factors. The associations between risk factor trends and stroke trends are stronger for women than for men.

Occupational, commuting, and leisure-time physical activity in relation to heart failure among finnish men and women

OBJECTIVES The purpose of this study was to examine the association of different levels of occupational, commuting, and leisure-time physical activity and heart failure (HF) risk. BACKGROUND The role of different types of physical activity in explaining the risk of HF is not properly established. METHODS Study cohorts included 28,334 Finnish men and 29,874 women who were 25 to 74 years of age and free of HF at baseline. Baseline measurement of different types of physical activity was used to predict incident HF. RESULTS During a mean follow-up of 18.4 years, HF developed in 1,868 men and 1,640 women. The multivariate adjusted (age; smoking; education; alcohol consumption; body mass index; systolic blood pressure; total cholesterol; history of myocardial infarction, valvular heart disease, diabetes, lung disease, and use of antihypertensive drugs; and other types of physical activity) hazard ratios of HF associated with light, moderate, and active occupational activity were 1.00, 0.90, and 0.83 (p = 0.005, for trend) for men and 1.00, 0.80, and 0.92 (p = 0.007, for trend) for women, respectively. The multivariate adjusted hazard ratios of HF associated with low, moderate, and high leisure-time physical activity were 1.00, 0.83, and 0.65 (p < 0.001, for trend) for men and 1.00, 0.84, and 0.75 (p < 0.001, for trend) for women, respectively. Active commuting had a significant inverse association with HF risk in women, but not in men, before adjustment for occupational and leisure-time physical activity. The joint effects of any 2 types of physical activity on HF risk were even greater. CONCLUSIONS Moderate and high levels of occupational or leisure-time physical activity are associated with a reduced risk of HF.