Prediction of functional outcome after stroke: Comparison of the Orpington Prognostic Scale and the NIH Stroke Scale

Background and Purpose - This study compared the ability of 2 stroke impairment scales, Orpington Prognostic Scale and National Institutes of Health (NIH) Stroke Scale, to predict disability as measured by the Barthel activities of daily living (ADL) Index and higher level of self-reported physical functioning as measured by the SF-36 physical functioning index (PFI) at 1, 3, and 6 months after stroke. Methods - The participants in this ongoing study are 184 individuals who sustained an eligible stroke and were recruited for the Kansas City Stroke Study. All patients were prospectively evaluated using standardized assessments at enrollment (within 14 days of stroke onset) and followed at 1, 3, and 6 months after stroke. Coefficient of determination (R²) was used to assess the ability of the 2 stroke scales to prognosticate outcomes. Results - Means and SDs of the Orpington Prognostic Scale and NIH Stroke Scale measured at baseline were 3.6±1.31 and 5.5±4.58, respectively. The Spearman's rank correlation between the 2 baseline measures was 0.83 (P=0.0001). The Orpington Prognostic Scale and the NIH Stroke Scale explained well the variance in Barthel ADL Index (P < 0.001). However, the Orpington Prognostic Scale explained more variance than did the NIH Stroke Scale. Similarly, the Orpington Prognostic Score explained more variance in higher level of physical function than did the NIH Stroke Scale. The amount of variance in Barthel ADL Index and SF-36 PFI, which were explained by both stroke severity measures, decreased over time. Conclusions - Our results demonstrate that in a sample of mostly mild and moderate strokes, the Orpington Prognostic Scale compared with the NIH Stroke Scale is simpler to use and is a slightly better predictor of ADL and higher levels of physical function.