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Updated: Mar 14, 2026
Computerized Adaptive Testing System of Functional Assessment of Stroke
Published on: January 7, 2019
Validity of a stroke severity index for administrative claims data research: a retrospective cohort study
Sheng-Feng Sung1, Cheng-Yang Hsieh2, Huey-Juan Lin3
1Division of Neurology, Department of Internal Medicine, Ditmanson Medical Foundation Chiayi Christian Hospital, 539 Zhongxiao Road, East District, Chiayi City, 60002, Taiwan.
Background:
Ascertaining stroke severity in claims data-based studies is difficult because clinical information is unavailable. We assessed the predictive validity of a claims-based stroke severity index (SSI) and determined whether it improves case-mix adjustment.
Methods:
We analyzed patients with acute ischemic stroke (AIS) from hospital-based stroke registries linked with a nationwide claims database. We estimated the SSI according to patient claims data. Actual stroke severity measured with the National Institutes of Health Stroke Scale (NIHSS) and functional outcomes measured with the modified Rankin Scale (mRS) were retrieved from stroke registries. Predictive validity was tested by correlating SSI with mRS. Logistic regression models were used to predict mortality.
Results:
The SSI correlated with mRS at 3 months (Spearman rho = 0.578; 95 % confidence interval [CI], 0.556-0.600), 6 months (rho = 0.551; 95 % CI, 0.528-0.574), and 1 year (rho = 0.532; 95 % CI 0.504-0.560). Mortality models with the SSI demonstrated superior discrimination to those without. The AUCs of models including the SSI and models with the NIHSS did not differ significantly.
Conclusions:
The SSI correlated with functional outcomes after AIS and improved the case-mix adjustment of mortality models. It can act as a valid proxy for stroke severity in claims data-based studies.
