Incidence of subarachnoid hemorrhage: role of region, year, and rate of computed tomography: a meta-analysis.

BACKGROUND AND PURPOSE The incidence of subarachnoid hemorrhage (SAH) has been estimated for many years at 10 to 15 per 100 000 person-years, but the most recent studies yield lower figures, of 6 to 8 per 100 000 person-years. To investigate the cause of this apparent decline, we studied the influence of year to study, rate of CT,and region. RESULTS Eighteen studies fulfilled predefined inclusion criteria. In three Finnish studies, the pooled incidence was 21.4 per 100 000 person-years (95% confidence interval [CI], 19.5 to 23.4); in 15 non-Finnish studies, it was 7.8 per 100 000 person-years (95% CI, 7.2 to 8.4). With univariate analysis, in non-Finnish studies the incidence decreased .96% for each percentage point increase of patients investigated with CT (rate ratio, -0.9904; 95% CI, 0.9878 to 0.9930). With 100% CT scanning, the incidence of SAH outside Finland is estimated at 6 per 100 000 person-years. The rate ratio for year of study was 0.952 (95% CI, 0.935 to 0.969) for each later year in the period 1960 to 1994. In multivariate analysis, only the use of CT was independently related to SAH incidence. For the Finnish studies, the rate ratios for use of CT and year to study were not statistically significant. We also found in six studies that incidence for women was 1.6 (95% CI, 1.1 to 2.3) times higher than that for men (7.1 [95% CI, 5.4 to 8.7] and 4.5 [95% CI, 3.1 to 5.8], respectively). CONCLUSIONS The actual incidence of SAH has remained stable over the last three decades; the apparent decline in incidence is entirely explained by the greater proportion of patients investigated with CT. The incidence of SAH in Finland is almost three times as high as in other parts of the world.

[1]  A. Algra,et al.  Risk Factors for Subarachnoid Hemorrhage A Systematic Review , 1996 .

[2]  A. Algra,et al.  Familial subarachnoid hemorrhage: Distinctive features and patterns of inheritance , 1995, Annals of neurology.

[3]  J. Parisi,et al.  Sudden death from aneurysmal subarachnoid hemorrhage , 1995, Neurology.

[4]  E. Vartiainen,et al.  Do changes in cardiovascular risk factors explain changes in mortality from stroke in Finland? , 1995, BMJ.

[5]  M. Schroll,et al.  Stroke incidence, case fatality, and mortality in the WHO MONICA project. World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease. , 1995, Stroke.

[6]  Gerald van Belle,et al.  Subarachnoid Hemorrhage and Hormonal Factors in Women: A Population-Based Case-Control Study , 1994, Annals of Internal Medicine.

[7]  H. Tunstall-Pedoe,et al.  Myocardial Infarction and Coronary Deaths in the World Health Organization MONICA Project: Registration Procedures, Event Rates, and Case‐Fatality Rates in 38 Populations From 21 Countries in Four Continents , 1994, Circulation.

[8]  G. Rinkel,et al.  SUBARACHNOID HEMORRHAGE. AUTHOR'S REPLY , 1994 .

[9]  S. Connor,et al.  Differences in Coronary Mortalit Can Be Explained by Differences in Cholesterol and Saturated Fat Intakes in 40 Countries but Not in France and Finland A Paradox , 1993, Circulation.

[10]  T. Koepsell,et al.  Clinical course of spontaneous subarachnoid hemorrhage , 1993, Neurology.

[11]  T. Inagawa.  Management outcome in the elderly patient following subarachnoid hemorrhage. , 1993, Journal of neurosurgery.

[12]  C. Anderson,et al.  Determining the incidence of different subtypes of stroke: results from the Perth Community Stroke Study, 1989–1990 , 1993, The Medical journal of Australia.

[13]  H. S. Jørgensen,et al.  Marked Increase of Stroke Incidence in Men Between 1972 and 1990 in Frederiksberg, Denmark , 1992, Stroke.

[14]  R. Fogelholm.  Subarachnoid hemorrhage in Finland. , 1992, Stroke.

[15]  G. Berglund,et al.  Stroke Registry in Malmö, Sweden , 1992, Stroke.

[16]  M. Giroud,et al.  Incidence and survival rates during a two-year period of intracerebral and subarachnoid haemorrhages, cortical infarcts, lacunes and transient ischaemic attacks. The Stroke Registry of Dijon: 1985-1989. , 1991, International journal of epidemiology.

[17]  E. Wijdicks,et al.  Nonaneurysmal perimesencephalic subarachnoid hemorrhage: CT and MR patterns that differ from aneurysmal rupture. , 1991, AJNR. American journal of neuroradiology.

[18]  S. Ricci,et al.  SEPIVAC: a community-based study of stroke incidence in Umbria, Italy. , 1991, Journal of neurology, neurosurgery, and psychiatry.

[19]  V. Salomaa,et al.  Epidemiology of subarachnoid hemorrhage in Finland from 1983 to 1985. , 1991, Stroke.

[20]  P. Sandercock,et al.  A prospective study of acute cerebrovascular disease in the community: the Oxfordshire Community Stroke Project--1981-86. 2. Incidence, case fatality rates and overall outcome at one year of cerebral infarction, primary intracerebral and subarachnoid haemorrhage. , 1990, Journal of neurology, neurosurgery, and psychiatry.

[21]  T. Pillar,et al.  Incidence, mortality, and case-fatality rate of stroke in northern Israel. , 1989, Stroke.

[22]  W M O'Fallon,et al.  Has there been a decline in subarachnoid hemorrhage mortality? , 1989, Stroke.

[23]  G. Murray,et al.  Outcome of aneurysmal subarachnoid hemorrhage in patients 66 years of age and older , 1988, Clinical Neurology and Neurosurgery.

[24]  B. Norrving,et al.  Epidemiology of stroke in Lund‐Orup, Sweden, 1983–85 , 1988, Acta neurologica Scandinavica.

[25]  A. Térent.  Increasing incidence of stroke among Swedish women. , 1988, Stroke.

[26]  J. Tuomilehto,et al.  Geographical variation in the major risk factors of coronary heart disease in men and women aged 35-64 years , 1988 .

[27]  P. Sandercock,et al.  GEOGRAPHICAL AND SECULAR TRENDS IN STROKE INCIDENCE , 1987, The Lancet.

[28]  N. Breslow,et al.  Statistical methods in cancer research. Volume II--The design and analysis of cohort studies. , 1987, IARC scientific publications.

[29]  R. Bonita,et al.  Subarachnoid hemorrhage: epidemiology, diagnosis, management, and outcome. , 1985, Stroke.

[30]  J. van Gijn,et al.  Perimesencephalic hemorrhage , 1985, Neurology.

[31]  J. Salonen,et al.  The incidence of stroke in the Kuopio area of East Finland. , 1985, Stroke.

[32]  P. Wolf,et al.  Subarachnoid and intracerebral hemorrhage , 1984, Neurology.

[33]  M. Kotila.  Declining Incidence and Mortality of Stroke? , 1984, Stroke.

[34]  C. Kase,et al.  Stroke in South Alabama: Incidence and Diagnostic Features - A Population Based Study , 1984, Stroke.

[35]  B. Schulte,et al.  Epidemiology of stroke in Tilburg, the Netherlands. The population‐based stroke incidence register: 2. Incidence, initial clinical picture and medical care, and three‐week case fatality. , 1982, Stroke.

[36]  J. Vandenbroucke,et al.  A SHORTCUT METHOD FOR CALCULATING THE 95 PER CENT CONFIDENCE INTERVAL OF THE STANDARDIZED MORTALITY RATIO , 1982 .

[37]  C. Date,et al.  Incidence of Stroke in Shibata, Japan: 1976–1978 , 1981, Stroke.

[38]  J. Gijn,et al.  Computed tomography in the diagnosis of subarachnoid haemorrhage and ruptured aneurysm , 1980, Clinical Neurology and Neurosurgery.

[39]  T. Sundt,et al.  The unchanging pattern of subarachnoid hemorrhage in a community , 1980, Neurology.

[40]  H. Adams,et al.  Pitfalls in the recognition of subarachnoid hemorrhage. , 1980, JAMA.

[41]  J. Marquardsen,et al.  Incidence of Stroke in Frederiksberg, Denmark , 1977, Stroke.

[42]  R. Fogelholm,et al.  Incidence and Early Prognosis of Stroke in Espoo‐Kauniainen Area, Finland, in 1972 , 1974, Stroke.

[43]  G. Gudmundsson.  Primary Subarachnoid Hemorrhage in Iceland , 1973, Stroke.

[44]  S. Pakarinen.  Incidence, aetiology, and prognosis of primary subarachnoid haemorrhage. A study based on 589 cases diagnosed in a defined urban population during a defined period. , 1967, Acta neurologica Scandinavica.

[45]  H Miller,et al.  Neurological disease in an English city. , 1966, Acta neurologica Scandinavica.