title: Risk of herpes zoster in CKD: a matched-cohort study based on administrative data.
abstract: BACKGROUND
  Immune system dysregulation is associated with end-stage renal disease. Although decreased cellular immunity increases susceptibility to herpes zoster, the risk of herpes zoster in patients with earlier stages of chronic kidney disease (CKD) is unclear.
  
  
  METHODS
  A matched-cohort study.
  
  
  METHODS
  Data from the Taiwan Longitudinal Health Insurance Database (LHID) for 2004-2006 were analyzed. The study cohort included patients 18 years or older given a diagnosis of CKD (excluding patients treated by dialysis or transplant) in 2004-2005 (n = 13,321). The comparison cohort (n = 66,605) included 5 randomly selected age- and sex-matched controls for each patient in the study cohort.
  
  
  METHODS
  CKD. Incident cases of CKD were identified using the Taiwan LHID. CKD was ascertained from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes.
  
  
  RESULTS
  Herpes zoster, ascertained from ICD-9-CM codes. All participants were followed up from the date of cohort entry until they developed herpes zoster or the end of 2006. Cox proportional hazard regressions were performed to compare the hazard rates of herpes zoster in the CKD cohort and the age- and sex-matched comparison cohort.
  
  
  RESULTS
  We identified 13,321 patients with a diagnosis of CKD who matched the inclusion criteria. 1,602 patients developed herpes zoster during the study period, of whom 353 were from the CKD cohort and 1,249 were from the comparison cohort. After adjusting for potential confounding factors, CKD was associated independently with greater risk of herpes zoster (HR, 1.60; 95% CI, 1.41-1.81).
  
  
  CONCLUSIONS
  Some patients with CKD or herpes zoster may have chosen not to seek medical care. Misclassification of CKD due to use of diagnostic codes also is a limitation.
  
  
  CONCLUSIONS
  This population-based cohort study indicated that patients with CKD are at increased risk of herpes zoster compared with the general population.
authors.affiliation: Department of Nephrology, Shuang Ho Hospital, Taipei Medical University, Taiwan.
authors.forename: Mei-Yi
authors.initials: MY
authors.lastname: Wu
authors.forename: Yung-Ho
authors.initials: YH
authors.lastname: Hsu
authors.forename: Chien-Ling
authors.initials: CL
authors.lastname: Su
authors.forename: Yuh-Feng
authors.initials: YF
authors.lastname: Lin
authors.forename: Hui-Wen
authors.initials: HW
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006562:Herpes Zoster / Q000453:epidemiology* / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology* / Q000276:immunology; D018570:Risk Assessment; D055815:Young Adult