Interobserver reliability of a clinical classification of acute cerebral infarction

The Oxfordshire Community Stroke Project (OCSP) clinical classification of subtypes of cerebral infarction (total and partial anterior circulation infarction, lacunar infarction, and posterior circulation infarction) can be used to predict early mortality, functional outcome, and whether the infarct was likely due to large- or small-vessel occlusion. The OCSP classification was originally developed and tested by neurologists as part of a community-based study of first-ever stroke, in which some cases were seen after the acute phase. We examined the interobserver reliability of the classification when used in everyday clinical practice in patients seen during the acute phase of stroke shortly after admission to the hospital.

Two clinicians independently assessed consecutive patients admitted to the hospital with an acute stroke and recorded both the neurological features and their opinion of the subtype of infarct.

Eighty-five patients were assessed. Interobserver agreement for the classification was moderate to good (kappa = 0.54; 95% confidence interval, 0.39 to 0.68). Differences in the assessment of the commonly elicited neurological signs explained many of the disagreements: interobserver agreement was good for some signs (hemiparesis [kappa = 0.77], dysphasia [kappa = 0.70]), moderate for some (hemianopia [kappa = 0.39]), and poor for others (sensory loss [kappa = 0.15]).

The classification was simple and practicable (and could be widely used in routine clinical practice, randomized controlled trials, and audit), and interobserver reliability was satisfactory.