Lifetime risks for aneurysmal subarachnoid haemorrhage: multivariable risk stratification.
OBJECTIVE
The overall incidence of aneurysmal subarachnoid haemorrhage (aSAH) in western populations is around 9 per 100 000 person-years, which confers to a lifetime risk of around half per cent. Risk factors for aSAH are usually expressed as relative risks and suggest that absolute risks vary considerably according to risk factor profiles, but such estimates are lacking. We aimed to estimate incidence and lifetime risks of aSAH according to risk factor profiles.


METHODS
We used data from 250 patients admitted with aSAH and 574 sex-matched and age-matched controls, who were randomly retrieved from general practitioners files. We determined independent prognostic factors with multivariable logistic regression analyses and assessed discriminatory performance using the area under the receiver operating characteristic curve. Based on the prognostic model we predicted incidences and lifetime risks of aSAH for different risk factor profiles.


RESULTS
The four strongest independent predictors for aSAH, namely current smoking (OR 6.0; 95% CI 4.1 to 8.6), a positive family history for aSAH (4.0; 95% CI 2.3 to 7.0), hypertension (2.4; 95% CI 1.5 to 3.8) and hypercholesterolaemia (0.2; 95% CI 0.1 to 0.4), were used in the final prediction model. This model had an area under the receiver operating characteristic curve of 0.73 (95% CI 0.69 to 0.76). Depending on sex, age and the four predictors, the incidence of aSAH ranged from 0.4/100 000 to 298/100 000 person-years and lifetime risk between 0.02% and 7.2%.


CONCLUSIONS
The incidence and lifetime risk of aSAH in the general population varies widely according to risk factor profiles. Whether persons with high risks benefit from screening should be assessed in cost-effectiveness studies.
Department of Neurology and Neurosurgery, Utrecht Stroke Centre, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, The Netherlands.
Monique H M
MH
Vlak
Gabriel J E
GJ
Rinkel
Paut
P
Greebe
Jacoba P
JP
Greving
Ale
A
Algra
D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000150:complications; D006973:Hypertension / Q000150:complications; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013345:Subarachnoid Hemorrhage / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics
Stroke; Subarachnoid Haemorrhage