title: Aging promotes progression of IgA nephropathy: a systematic review and meta-analysis.
abstract: BACKGROUND
  There has been considerable interest in whether old age is associated with IgA nephropathy (IgAN) progression, which is still controversial.
  
  
  METHODS
  We searched multiple databases for studies published from 1980 to 2012. The inclusion criteria were case-control, cohort studies published in any language. The included studies needed to have an older group. IgAN was proven by biopsy.
  
  
  RESULTS
  We included 9 studies with a total of 6,543 patients. The meta-analyses of other risk factors between the older group (>50 years old) and the non-older group (15-50 years old) found significant differences in the presence of hypertension, proteinuria, serum cholesterol levels and baseline renal function. In the overall analysis, compared to the non-older group, older age significantly increased the incidence of developing end-stage renal disease [ESRD; relative risk (RR) random model 1.95; 95% CI: 1.27-3.01]. In the subgroup analyses, we found the age limit and traditional risk factors of IgAN may be the sources of heterogeneity between studies. Moreover, the RR (2.56) of the Asian countries was much higher than the RR (1.11) of the European countries.
  
  
  CONCLUSIONS
  This comprehensive review revealed that old age is a real risk factor for IgAN progression to ESRD. The incidence of ESRD in the older IgAN patients was 1.95 times higher than that in the non-older IgAN patients. Moreover, the risk of IgAN progression to ESRD of the older patients in Asia was higher than that of the older patients in Europe.
authors.affiliation: Department of Nephrology, State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital, Beijing, PR China.
authors.forename: Zhi-Yu
authors.initials: ZY
authors.lastname: Duan
authors.forename: Guang-Yan
authors.initials: GY
authors.lastname: Cai
authors.forename: Yi-Zhi
authors.initials: YZ
authors.lastname: Chen
authors.forename: Shuang
authors.initials: S
authors.lastname: Liang
authors.forename: Shu-Wen
authors.initials: SW
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Qiu
authors.forename: Shu-Peng
authors.initials: SP
authors.lastname: Lin
authors.forename: Xue-Guang
authors.initials: XG
authors.lastname: Zhang
authors.forename: Xiang-Mei
authors.initials: XM
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D001706:Biopsy / Q000379:methods; D016022:Case-Control Studies; D015331:Cohort Studies; D018450:Disease Progression; D005922:Glomerulonephritis, IGA / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000473:pathology*; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D055815:Young Adult