title: [First episode non-traumatic subarachnoid haemorrhage. An epidemiological study of incidence and of arterial hypertension as a risk factor].
abstract: OBJECTIVE
  Our aim was to conduct an epidemiological study of the incidence of non-traumatic subarachnoid haemorrhage (NTSAH) and to evaluate a history of arterial hypertension (AHT) as a risk factor (RF). We also sought to determine the gross annual rate (GAR) and specific rates, by sex and age, of first episode non-traumatic subarachnoid haemorrhage (FENTSAH) adjusted to the Censo Nacional de Población de la Argentina (CNPA), and to carry out a population-based case-control study about the history of AHT as a RF in an Argentine community.
  
  
  METHODS
  Our institution, the Hospital Privado de Comunidad de Mar del Plata, Argentina, attends a population of about 89,500 individuals exclusively and completely. There is a single filing system of case histories with all the diagnoses in a database. Patients who suffered a FENTSAH between the years 1992 and 1996 (n=62) were investigated to determine the specific GAR by sex and age and adjusted to the 1991 CNPA. The population was compared at random with two controls per case for the study of a history of AHT as a RF, and was then stratified according to sex and age.
  
  
  RESULTS
  1. GAR: 13.6/100,000 inhab./year; 2. Specific rate for males: 10.5/100,000 inhab./year; 3. Specific rate for females: 15.9/100,000 inhab./year; 4. CNPA adjusted rate: 7.3/100,000 inhab./year; 5. A significantly important number of patients with FENTSAH presented a history of hypertension as compared to controls subjects (odds ratio: 4.73; CI 95%: 2.39 9.34).
  
  
  CONCLUSIONS
  Our rates are not substantially different from the rates found in other western countries and our findings indicate that a history of AHT is a RF for FENTSAH.
authors.affiliation: Servicio de Neurología, Hospital Privado de Comunidad, Mar del Plata, Argentina. gustavomartin-echevarria@hotmail.com
authors.forename: G
authors.initials: G
authors.lastname: Echevarría-Martín
authors.forename: S E
authors.initials: SE
authors.lastname: Gonorazky
authors.forename: M
authors.initials: M
authors.lastname: Gáspari
authors.forename: C
authors.initials: C
authors.lastname: Valussi
authors.forename: R
authors.initials: R
authors.lastname: Femminini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001118:Argentina / Q000453:epidemiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000453:epidemiology* / Q000209:etiology