title: Validation of a novel claims-based stroke severity index in patients with intracerebral hemorrhage.
abstract: BACKGROUND
  Stroke severity is an important outcome predictor for intracerebral hemorrhage (ICH) but is typically unavailable in administrative claims data. We validated a claims-based stroke severity index (SSI) in patients with ICH in Taiwan.
  
  
  METHODS
  Consecutive ICH patients from hospital-based stroke registries were linked with a nationwide claims database. Stroke severity, assessed using the National Institutes of Health Stroke Scale (NIHSS), and functional outcomes, assessed using the modified Rankin Scale (mRS), were obtained from the registries. The SSI was calculated based on billing codes in each patient's claims. We assessed two types of criterion-related validity (concurrent validity and predictive validity) by correlating the SSI with the NIHSS and the mRS. Logistic regression models with or without stroke severity as a continuous covariate were fitted to predict mortality at 3, 6, and 12 months.
  
  
  RESULTS
  The concurrent validity of the SSI was established by its significant correlation with the admission NIHSS (r = 0.731; 95% confidence interval [CI], 0.705-0.755), and the predictive validity was verified by its significant correlations with the 3-month (r = 0.696; 95% CI, 0.665-0.724), 6-month (r = 0.685; 95% CI, 0.653-0.715) and 1-year (r = 0.664; 95% CI, 0.622-0.702) mRS. Mortality models with NIHSS had the highest area under the receiver operating characteristic curve, followed by models with SSI and models without any marker of stroke severity.
  
  
  CONCLUSIONS
  The SSI appears to be a valid proxy for the NIHSS and an effective adjustment for stroke severity in studies of ICH outcome with administrative claims data.
authors.affiliation: Division of Neurology, Department of Internal Medicine, Ditmanson Medical Foundation Chiayi Christian Hospital, Chiayi City, Taiwan.
authors.forename: Ling-Chien
authors.initials: LC
authors.lastname: Hung
authors.affiliation: Division of Neurology, Department of Internal Medicine, Ditmanson Medical Foundation Chiayi Christian Hospital, Chiayi City, Taiwan.
authors.forename: Sheng-Feng
authors.initials: SF
authors.lastname: Sung
authors.affiliation: Department of Neurology, Tainan Sin Lau Hospital, Tainan, Taiwan. Electronic address: chengyanghsieh@gmail.com.
authors.forename: Cheng-Yang
authors.initials: CY
authors.lastname: Hsieh
authors.affiliation: Department of Information Management and Institute of Healthcare Information Management, National Chung Cheng University, Chiayi County, Taiwan.
authors.forename: Ya-Han
authors.initials: YH
authors.lastname: Hu
authors.affiliation: Department of Neurology, Chi Mei Medical Center, Tainan, Taiwan.
authors.forename: Huey-Juan
authors.initials: HJ
authors.lastname: Lin
authors.affiliation: Department of Neurology, Landseed Hospital, Tao-Yuan County, Taiwan; Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Yu-Wei
authors.initials: YW
authors.lastname: Chen
authors.affiliation: Institute of Clinical Pharmacy and Pharmaceutical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yea-Huei Kao
authors.initials: YK
authors.lastname: Yang
authors.affiliation: Department of Pharmacy Systems, Outcomes & Policy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: Sue-Jane
authors.initials: SJ
authors.lastname: Lin
mesh_terms: D000368:Aged; D002543:Cerebral Hemorrhage / Q000401:mortality / Q000628:therapy*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007344:Insurance Claim Reporting; D008297:Male; D008875:Middle Aged; D012042:Registries; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D020521:Stroke; D013624:Taiwan / Q000453:epidemiology; D016896:Treatment Outcome
keywords: Administrative claims data; Intracerebral hemorrhage; National Health Insurance Research Database; Outcomes research; Stroke severity