Aug 10 2012
By Eleanor McDermid, Senior MedWire Reporter
Age is only predictive of poor outcome after aneurysmal subarachnoid hemorrhage (SAH) because of its association with hydrocephalus, say researchers.
Hydrocephalus occurred in 24.1% of the 933 patients in the study, and their likelihood for poor 1-year outcomes worsened with advancing age, whereas age did not influence outcomes in those without this complication. Hydrocephalus was more common in older patients, occurring in 44.0% of those aged at least 60 years versus 32.6% of younger patients.
Vincent Degos (Université Pierre et Marie Curie, Paris, France) and co-workers diagnosed hydrocephalus on admission computed tomography scans, accounting for sulci sizes to distinguish brain atrophy from acute hydrocephalus. They treated all patients with hydrocephalus with an external ventricular drain.
"Because all patients with a positive diagnosis of admission hydrocephalus were treated, we were not able to evaluate the potential negative impact of untreated hydrocephalus in elderly patients," the researchers note in Anesthesiology.
The best predictive model distinguished between patients with and without poor 1-year outcomes (modified Rankin Scale 4-6) with an accuracy of 84%. This model comprised admission intracranial hypertension, severe intracranial hypertension, ischemic vasospasm, rebleeding, endovascular and surgical complications, high Fisher score, age of 60 years or older, and hydrocephalus.
Accounting for the effect of hydrocephalus on the association between age and outcomes rendered the individual effects of age and hydrocephalus nonsignificant and improved the overall accuracy of the model slightly but significantly, to 85%.
Hydrocephalus was not associated with any comorbidity, including hypertension and dyslipidemia, and was not related to smoking status.
Degos et al comment that the comorbidity data "can be unreliable because of interindividual variability in diagnosis-seeking behavior and treatment adherence." Thus they chose to focus on factors that are simple to assess in the intensive care unit, namely, age and neurologic events.
Other neurologic events had no bearing on the relationship between age and outcome, although the team found, in line with previous findings, that vasospasm became less common with increasing patient age.
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