Reliability and validity of estimating the NIH stroke scale score from medical records.
OBJECTIVE
The aim of our study was to determine whether the National Institutes of Health Stroke Scale (NIHSS) can be estimated retrospectively from medical records. The NIHSS is a quantitative measure of stroke-related neurological deficit with established reliability and validity for use in prospective clinical research. Recently, retrospective observational studies have estimated NIHSS scores from medical records for quantitative outcome analysis. The reliability and validity of estimation based on chart review has not been determined.


METHODS
Thirty-nine patients were selected because their NIHSS scores were formally measured at admission and discharge. Handwritten notes from medical records were abstracted and NIHSS scores were estimated by 6 raters who were blinded to the actual scores. Estimated scores were compared among raters and with the actual measured scores.


RESULTS
Interrater reliability was excellent, with an intraclass correlation coefficient of 0.82. Scores were well calibrated among the 6 raters. Estimated NIHSS scores closely approximated the actual scores, with a probability of 0.86 of correctly ranking a set of patients according to 5-point interval categories (as determined by the area under the receiver-operator characteristic curve). Patients with excellent outcomes (NIHSS score of </=5) could be identified with sensitivity of 0.72 and specificity of 0.89. There were no significant differences between these parameters at admission and discharge.


CONCLUSIONS
For the purposes of retrospective studies of acute stroke outcome, the NIHSS can be abstracted from medical records with a high degree of reliability and validity.
Kasner
S E
SE
Department of Neurology, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania Medical Center, Philadelphia, PA, USA. kasner@mail.med.upenn.edu
Chalela
J A
JA
Luciano
J M
JM
Cucchiara
B L
BL
Raps
E C
EC
McGarvey
M L
ML
Conroy
M B
MB
Localio
A R
AR
D002561:Cerebrovascular Disorders / Q000145:classification* / Q000175:diagnosis; D006801:Humans; D008499:Medical Records / Q000706:statistics & numerical data*; D009316:National Institutes of Health (U.S.); D009483:Neuropsychological Tests; D010343:Patient Admission; D010351:Patient Discharge; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014481:United States