Utility of outcome measures after treatment for intracranial aneurysms - A prospective trial involving 520 patients

Background and Purpose - As different intracranial aneurysm treatments are compared in upcoming trials, complete characterization of patient outcomes will be critical. Currently, graded scales such as the Glasgow Outcome Score (GOS) or the Rankin scale are commonly used. Our objective was to test the utility of different outcome instruments in patients after aneurysm treatment. Methods - A prospective trial comparing 6 outcome instruments at 3 to 12 months after aneurysm treatment: the Rankin and GOS, the Barthel Index ( activities of daily living), the National Institutes of Health Stroke Score (NIHSS) ( neurological examination), the Short Form-36 ( subjective experience of recovery), and the Mini-Mental Status Examination (MMSE) ( cognitive recovery). All tests were administered to each patient at the same time by an independent grader. The Spearman correlation coefficient was calculated between instruments ( with 1 representing complete correlation). Results - In 4 years, 520 patients with 618 ruptured or unruptured aneurysms were enrolled: 385 surviving patients were tested. The resulting scores showed a wide distribution for the MMSE and the SF-36, but almost no variability for the Barthel Index and NIHSS. Correlations between scores were poor: 0.15 when the GOS was compared with the MMSE; 0.27 compared with the SF-36. Many patients given the highest GOS or Rankin scores showed significant cognitive deficits. Conclusions - These data indicate that a single graded scale does not address all aspects of recovery after aneurysm treatment, particularly cognitive dysfunction and the patient's perception of health. The implications of these findings are discussed.