Predicting prognosis after stroke: a placebo group analysis from the National Institute of Neurological Disorders and Stroke rt-PA Stroke Trial.

Abstract

Physicians are often asked to predict outcome after acute stroke. Very little information is available that can reliably predict the likelihood of severe disability or death. To develop a practical method for predicting a poor outcome after acute ischemic stroke. Data from the placebo arms of Parts 1 and 2 of the National Institute of Neurological Disorders and Stroke rt-PA [recombinant tissue plasminogen activator] Stroke Trial were used to identify variables that could predict a poor outcome, defined as moderately severe disability, severe disability, or death (Modified Rankin Scale score >3) 3 months after stroke. Baseline variables that predicted poor outcome were the NIH Stroke Scale (NIHSS) >17 plus atrial fibrillation, yielding a positive predictive value (PPV) of 96% (95% CI, 88 to 100%). The best predictor at 24 hours was NIHSS >22, yielding a PPV of 98% (95% CI, 93 to 100%). The best predictor at 7 to 10 days was NIHSS >16, yielding a PPV of 92% (95% CI, 85 to 99%). Patients with a severe neurologic deficit after acute ischemic stroke, as measured by the NIHSS, have a poor prognosis. During the first week after acute ischemic stroke, it is possible to identify a subset of patients who are highly likely to have a poor outcome. These findings require confirmation in a separate study.