title: Comparison of risk adjustment methods in patients with liver disease using electronic medical record data.
abstract: BACKGROUND
  Risk adjustment is essential for valid comparison of patients' health outcomes or performances of health care providers. Several risk adjustment methods for liver diseases are commonly used but the optimal approach is unknown. This study aimed to compare the common risk adjustment methods for predicting in-hospital mortality in cirrhosis patients using electronic medical record (EMR) data.
  
  
  METHODS
  The sample was derived from Beijing YouAn hospital between 2010 and 2014. Previously validated EMR extraction methods were applied to define liver disease conditions, Charlson comorbidity index (CCI), Elixhauser comorbidity index (ECI), Child-Turcotte-Pugh (CTP), model for end-stage liver disease (MELD), MELD sodium (MELDNa), and five-variable MELD (5vMELD). The performance of the common risk adjustment models as well as models combining disease severity and comorbidity indexes for predicting in-hospital mortality was compared using c-statistic.
  
  
  RESULTS
  Of 11,121 cirrhotic patients, 69.9% were males and 15.8% age 65 or older. The c-statistics across compared models ranged from 0.785 to 0.887. All models significantly outperformed the baseline model with age, sex, and admission status (c-statistic: 0.628). The c-statistics for the CCI, ECI, MELDNa, and CTP were 0.808, 0.825, 0.849, and 0.851, respectively. The c-statistic was 0.887 for combination of CTP and ECI, and 0.882 for combination of MELDNa score and ECI.
  
  
  CONCLUSIONS
  The liver disease severity indexes (i.e., CTP and MELDNa score) outperformed the CCI and ECI for predicting in-hospital mortality among cirrhosis patients using Chinese EMRs. Combining liver disease severity and comorbidities indexes could improve the discrimination power of predicting in-hospital mortality.
authors.affiliation: Beijing YouAn Hospital, Capital Medical University, Beijing, China.|Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Beijing YouAn Hospital, Capital Medical University, Beijing, China. liningya@ccmu.edu.cn.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada.|Department of Economics, University of Calgary, Calgary, AB, Canada.
authors.forename: Mingshan
authors.initials: M
authors.lastname: Lu
authors.affiliation: Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada.|Division of General Surgery, Department of Medicine, University of Calgary, Calgary, AB, Canada.
authors.forename: Elijah
authors.initials: E
authors.lastname: Dixon
authors.affiliation: Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada.|Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, AB, Canada.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Myers
authors.affiliation: Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada.
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: Jolley
authors.affiliation: Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada.
authors.forename: Hude
authors.initials: H
authors.lastname: Quan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D057286:Electronic Health Records / Q000706:statistics & numerical data*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008103:Liver Cirrhosis / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D020379:Risk Adjustment / Q000379:methods*; D012720:Severity of Illness Index; D055815:Young Adult
keywords: Electronic medical record; In-hospital mortality; Liver disease; Risk adjustment