title: Predicting mortality of incident dialysis patients in Taiwan--a longitudinal population-based study.
abstract: BACKGROUND
  Comorbid conditions are highly prevalent among patients with end-stage renal disease (ESRD) and index score is a predictor of mortality in dialysis patients. The aim of this study is to perform a population-based cohort study to investigate the survival rate by age and Charlson comorbidity index (CCI) in incident dialysis patients.
  
  
  METHODS
  Using the catastrophic illness registration of the Taiwan National Health Insurance Research Database for all patients from 1 January 1998 to 31 December 2008, individuals newly diagnosed with ESRD and receiving dialysis for more than 90 days were eligible for our study. Individuals younger than 18 years or renal transplantation patients either before or after dialysis were excluded. We calculated the CCI, age-weighted CCI by Deyo-Charlson method according to ICD-9 code and categorized CCI into six groups as index scores <3, 4-6, 7-9, 10-12, 13-15, >15. Cox regression models were used to analyze the association between age, CCI and survival, and the risk markers of survival.
  
  
  RESULTS
  There were 79,645 incident dialysis patients, whose mean age (± SD) was 60.96 (±13.92) years; 51.43% of patients were women and 51.2% were diabetic. In cox proportional hazard models and stratifying by age, older patients had significantly higher mortality than younger patients. The mortality risk was higher in persons with higher CCI as compared with low CCI. Mortality increased steadily with higher age or comorbidity both for unadjusted and for adjusted models. For all age groups, mortality rates increased in different CCI groups with the highest rates occurring in the oldest age groups.
  
  
  CONCLUSIONS
  Age and CCI are both strong predictors of survival in Taiwan. The older age or higher comorbidity index in incident dialysis patient is associated with lower long-term survival rates. These population-based estimates may assist clinicians who make decisions when patients need long-term dialysis.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Ping-Hsun
authors.initials: PH
authors.lastname: Wu
authors.forename: Yi-Ting
authors.initials: YT
authors.lastname: Lin
authors.forename: Tzu-Chi
authors.initials: TC
authors.lastname: Lee
authors.forename: Ming-Yen
authors.initials: MY
authors.lastname: Lin
authors.forename: Mei-Chuan
authors.initials: MC
authors.lastname: Kuo
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Chiu
authors.forename: Shang-Jyh
authors.initials: SJ
authors.lastname: Hwang
authors.forename: Hung-Chun
authors.initials: HC
authors.lastname: Chen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology / Q000401:mortality*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000453:epidemiology / Q000401:mortality*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000401:mortality*; D012720:Severity of Illness Index; D015996:Survival Rate; D013624:Taiwan / Q000453:epidemiology