Jorma Torppa

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.

Epidemiology of subarachnoid hemorrhage in Finland from 1983 to 1985.

The age-standardized incidence of subarachnoid hemorrhage was 33/100,000/yr among Finnish men and 25/100,000/yr among Finnish women. Subarachnoid hemorrhage represented 11% of all strokes detected during 1983-1985 in the community-based stroke register in three areas of Finland. Age-standardized mortality from subarachnoid hemorrhage was 18/100,000/yr among men and 12/100,000/yr among women aged 25-74 years, representing in men 22% and in women 23% of all deaths from stroke in the register. The case-fatality rate of subarachnoid hemorrhage was high: 35% among men and 33% among women within 2 days after the onset of the stroke attack and 48% in men and 46% in women at 1 month. Our findings suggest that the incidence and mortality of subarachnoid hemorrhage in Finland are among the highest worldwide, although differences in criteria, study methods, and classification procedures reduce the comparability of studies from different countries. The occurrence of subarachnoid hemorrhage in our present study is also higher than that previously reported in this country. We believe that this is more likely due to changes in diagnostic classification and improvements in detection of the disease than to a real increase in the morbidity and mortality of subarachnoid hemorrhage.

Seasonal Variation in the Occurrence of Stroke in a Finnish Adult Population: The FINMONICA Stroke Register

BACKGROUND AND PURPOSE Seasonal influence on the incidence of and mortality from cerebrovascular disease has been reported during the last three decades, but generally with some discrepancy in results, particularly regarding stroke subtypes. The aim of this study was to examine seasonal variation in the incidence, mortality, and case-fatality rate of stroke in data from the FINMONICA population-based stroke register. METHODS During 1982 to 1992, 15449 stroke events were registered in the monitored populations aged 25 to 99 years in three geographic areas of Finland: the provinces of Kuopio and North Karelia in eastern Finland and the Turku/Loimaa area in southwestern Finland. We analyzed the seasonal and monthly incidence, mortality, and case-fatality rate of stroke and subtypes of stroke by pooling the data for the three areas and stratifying by sex and age. RESULTS The rate of occurrence of ischemic stroke events was 12% (95% confidence interval [CI], 5% to 20%) greater in men and 11% (95% CI, 4% to 19%) greater in women in winter than in summer. For intracerebral hemorrhage, we observed a 28% (95% CI, 3% to 58%) greater rate of occurrence in men and a 33% (95% CI, 6% to 66%) greater rate of occurrence in women in winter than in summer. The occurrence of subarachnoid hemorrhage did not vary significantly by season. The greater incidence of ischemic strokes in winter was particularly prominent among men aged 25 to 64 years and less prominent in elderly men and in women. The 28-day case-fatality rate of ischemic stroke showed significant seasonal variation only in women (P = .001), with the lowest rate in summer. CONCLUSIONS There is a significantly greater incidence of ischemic strokes and intracerebral hemorrhages during winter in Finland. Further research that also takes meteorologic and sociodemographic factors into account is warranted, since it may help to determine new ways to prevent strokes.

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.

Atrial Fibrillation and Stroke Mortality and Causes of Death After the First Acute Ischemic Stroke

BACKGROUND AND PURPOSE Atrial fibrillation (AF) is a risk factor for stroke. This study was undertaken to determine the influence of AF on the mortality of stroke patients and on the causes of death after a stroke event. METHODS Patients with first ischemic stroke who were .35 to 74 years old and registered in the FINMONICA stroke register during 1982 through 1992 were analyzed (n = 6912). There were 642 patients with AF (9.3%) (mean age, 67 years) and 6270 patients without AF (90.3%) (mean age, 63 years). The association between AF and stroke mortality was investigated by use of logistic regression and Cox proportional hazards models. RESULTS Mortality was higher in the AF group both at 28 days (19.5% versus 14.4%, P < .001) and 1 year after the attack (30.5% versus 21.8%, P < .001). After adjustment for age and sex, the odds ratio for 28-day case fatality (AF versus non-AF) was 1.27 (95% CI, 1.03 to 1.56; P = .003), and that for 1-year mortality was 1.36 (95% CI, 1.14 to 1.63; P < .001). In the proportional hazards model, AF was a significant independent risk factor for 1-year mortality (hazard ratio, 1.26; 95% CI, 1.09 to 1.46; P = .002). Cardiac causes of death were more common in the AF group at the acute stage. In the course of 1 year, there were no differences in the distributions of causes of death. CONCLUSIONS Stroke patients with AF are at high risk of death both at the acute phase of stroke and during the subsequent year after the first acute stroke event. Mortality from cardiac diseases prevailed in the AF group during the acute phase of stroke. Careful cardiac evaluation and treatment are essential in patients with AF and stroke.

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.

Ten-Year Trends in Stroke Incidence and Mortality in the FINMONICA Stroke Study

BACKGROUND AND PURPOSE The trends in stroke incidence reported so far have not been entirely consistent, although declining trends in mortality from stroke have been reported from a number of studies around the world. This study aims to evaluate the 10-year trends (from 1983 through 1992) in incidence, attack rate, and mortality of stroke in the Finnish population. METHODS A population-based stroke register was set up in the early 1980s to collect data on all suspected events of acute stroke that occurred in the population aged 25 to 74 years permanently residing in three geographic areas of Finland: the provinces of Kuopio and North Karelia in eastern Finland and the Turku-Loimaa area in southwestern Finland. Trends in age-standardized attack rates, incidence, and mortality were calculated for the period studied. RESULTS During the 10-year study period, 11 392 acute stroke events occurred in the monitored populations. A statistically significant decline was observed in the pooled FINMONICA data, both in the incidence of stroke (-1.7% with 95% confidence interval [CI], -3.0% to -0.5% per year in men; -2.2% with 95% CI, -3.6% to -0.7% per year in women) and in mortality from stroke (-5.2% with 95% CI, -8.2% to -2.2% per year; -4.7% with 95% CI, -8.2% to -1.2% per year). The attack rate of stroke also declined significantly in both sexes. When the areas were considered separately, the declining trends were observed within each area. The decline in incidence of stroke was, however, statistically significant only among men and women in Kuopio and among women in Turku/Loimaa. Mortality declined significantly in all three areas among men but among women only in Kuopio. The incidence to mortality rate ratio increased during the study period, indicating a steeper fall in mortality than in incidence. CONCLUSIONS A substantial decline in both stroke incidence and mortality was observed in the adult and elderly population in the FINMONICA study areas. Part but not all of the decline in stroke mortality, observed also in the official mortality statistics, can be attributed to the decline in stroke incidence during this 10-year period.

Trends in coronary events in Finland during 1983–1997; The FINAMI study

AIMS To analyse the trends in incidence, recurrence, case fatality, and treatments of acute coronary events in Finland during the 15-year period 1983-97. METHODS AND RESULTS Population-based MI registration has been carried out in defined geographical areas, first as a part of the FINMONICA Project and then continued as the FINAMI register. During the study period, 6501 coronary heart disease (CHD) events were recorded among men and 1778 among women aged 35-64 years. The CHD mortality declined on average 6.4%/year (95% confidence interval -5.4, -7.4%) among men and 7.0%/year (-4.7, -9.3%) among women. The mortality from recurrent events declined even more steeply, 9.9%/year (-8.3, -11.4%) among men and 9.3%/year (-5.1, -13.4%) among women. The proportion of recurrent events of all CHD events also declined significantly in both sexes. Of all coronary deaths, 74% among men and 61% among women took place out-of-hospital. The decline in 28-day case fatality was 1.3%/year (-0.3, -2.3%) among men and 3.1%/year (-0.7, -5.5%) among women. CONCLUSIONS The study period was characterized by a marked reduction in the occurrence of recurrent CHD events and a relatively modest reduction in the 28-day case fatality. The findings suggest that primary and secondary prevention have played the main roles in the decline in CHD mortality in Finland.

Decline in Out-of-Hospital Coronary Heart Disease Deaths Has Contributed the Main Part to the Overall Decline in Coronary Heart Disease Mortality Rates Among Persons 35 to 64 Years of Age in Finland The FINAMI Study

Background—Out-of-hospital deaths constitute the majority of all coronary heart disease (CHD) deaths and are therefore of considerable public health significance. Methods and Results—We used population-based myocardial infarction register data to examine trends in out-of-hospital CHD deaths in Finland during 1983 to 1997. We included in out-of-hospital deaths also deaths in the emergency room and all deaths within 1 hour after the onset of symptoms. Altogether, 3494 such events were included in the analyses. The proportion of out-of-hospital deaths of all CHD deaths depended on age and gender. In the age group 35 to 64 years, it was 73% among men and 60% among women. These proportions did not change during the study. The annual average decline in the age-standardized out-of-hospital CHD death rate was 6.1% (95% CI, −7.3, −5.0%) among men and 7.0% (−10.0, −4.0%) among women. These declines contributed among men 70% and among women 58% to the overall decline in CHD mortality rate. In all, 58% of the male and 52% of the female victims of out-of-hospital CHD death had a history of symptomatic CHD. Among men with a prior history of myocardial infarction, the annual average decline in out-of-hospital CHD deaths was 5.3% (−7.2, −3.2%), and among men without such history the decline was 2.9% (−4.4, −1.5%). Among women, the corresponding changes were −7.8% (−14.2, −1.5%) and −4.5% (−8.0, −1.0%). Conclusions—The decline in out-of-hospital CHD deaths has contributed the main part to the overall decline in CHD mortality rates among persons 35 to 64 years of age in Finland.