title: Impact of age on peritonitis risk in peritoneal dialysis patients: an era effect.
abstract: OBJECTIVE
  Despite reductions in the frequency of peritoneal dialysis (PD)-related infectious complications over time, peritonitis and catheter infection remain important causes of morbidity and mortality. Given the increasing number of elderly patients reaching end-stage renal disease, making informed decisions about PD utilization is contingent on an understanding of the infectious complications of PD in this population. We therefore studied the impact of age on infection rates, organisms and outcomes.
  
  
  METHODS
  On the basis of data collected from 1996 to 2005 in the multicenter Baxter Peritonitis Organism Exit sites Tunnel infections database, the study population included 4247 incident Canadian PD patients: 1265 patients aged > or =70 yr and 2982 patients aged <70 yr. We defined two eras of PD initiation: 1996 to 2000 and 2001 to 2005.
  
  
  RESULTS
  In a negative binomial model, older age was independently associated with a higher peritonitis rate (rate ratio [RR] 1.06 per decade increase; 95% CI 1.01 to 1.10; P = 0.008). However, this association was present only among those who initiated PD at an earlier time (RR 1.13 per decade increase; 95% CI 1.07 to 1.20; P < 0.001 in 1996 to 2000 versus 1.01 per decade increase; 95% CI 0.95 to 1.06; P = 0.81 in 2001 to 2005). Catheter-related infections were less frequent with increasing age regardless of era (RR 0.93 per decade increase; 95% CI 0.89 to 0.97).
  
  
  CONCLUSIONS
  The higher peritonitis rate observed in elderly patients may represent an era effect, as age was not associated with peritonitis among patients initiating PD between 2001 and 2005. In addition, catheter infection was less frequent with increasing age.
authors.affiliation: Department of Medicine, Division of Nephrology, St Michael's Hospital, Toronto, Ontario, Canada. nessims@smh.toronto.on.ca
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Nessim
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Bargman
authors.forename: Peter C
authors.initials: PC
authors.lastname: Austin
authors.forename: Ken
authors.initials: K
authors.lastname: Story
authors.forename: Sarbjit V
authors.initials: SV
authors.lastname: Jassal
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D055499:Catheter-Related Infections / Q000453:epidemiology / Q000209:etiology* / Q000382:microbiology; D002408:Catheters, Indwelling / Q000009:adverse effects; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000453:epidemiology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010530:Peritoneal Dialysis / Q000009:adverse effects* / Q000295:instrumentation / Q000706:statistics & numerical data; D010538:Peritonitis / Q000453:epidemiology / Q000209:etiology* / Q000382:microbiology; D011446:Prospective Studies; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors