title: Influence of climate on the incidence of peritoneal dialysis-related peritonitis.
abstract: OBJECTIVE
  The use of peritoneal dialysis has expanded in many developing subtropical countries; however, the role of climatic factors in dialysis-related peritonitis has not been studied in detail.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  A single regional dialysis unit in a university teaching hospital.
  
  
  METHODS
  We reviewed all cases of dialysis-related peritonitis treated in our dialysis unit from January 1995 to December 2001. Information was collected on demographic data, microbiologic etiology, associated catheter exit-site infection, and clinical response.
  
  
  RESULTS
  In 24,059 patient-months of follow-up, 1344 episodes of peritonitis were recorded. There were significantly more peritonitis episodes in July and August [odds ratio 1.17, 95% confidence interval (CI) 1.03-1.32], and fewer peritonitis episodes in December (odds ratio 0.79, 95% CI 0.61-0.98). There was also a trend of more peritonitis in March (odds ratio 1.18, 95% CI 0.97-1.41), but the difference was not statistically significant. When the incidence of peritonitis caused by individual bacterial species was further analyzed, we found a significant seasonal variation in the rate of peritonitis caused by gram-negative bacteria, except Pseudomonas (overall chi-square test, p = 0.002). A similar trend of seasonal variation was also observed in gram-positive peritonitis, but the result was not statistically significant. There was significant seasonal variation in the rate of peritonitis that had coexisting exit-site infection (overall chi-square test, p = 0.02), with peak incidence in July. However, the proportion of peritonitis that had coexisting exit-site infection did not have significant seasonal variation. There was significant correlation between monthly peritonitis rate and average humidity (r = -0.346, p < 0.002) and temperature (r = -0.264, p = 0.015).
  
  
  CONCLUSIONS
  There is substantial seasonal variation in the incidence of dialysis-related peritonitis, with peak incidence in the months that are hot and humid. Keeping a cool and dry living environment may help to reduce peritonitis in peritoneal dialysis patients in tropical countries.
authors.affiliation: Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China. ccszeto@cuhk.edu.hk
authors.forename: Cheuk-Chun
authors.initials: CC
authors.lastname: Szeto
authors.forename: Kai-Ming
authors.initials: KM
authors.lastname: Chow
authors.forename: Teresa Yuk-Hwa
authors.initials: TY
authors.lastname: Wong
authors.forename: Chi-Bon
authors.initials: CB
authors.lastname: Leung
authors.forename: Philip Kam-Tao
authors.initials: PK
authors.lastname: Li
mesh_terms: D002980:Climate; D005500:Follow-Up Studies; D006801:Humans; D006813:Humidity; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D010538:Peritonitis / Q000453:epidemiology* / Q000209:etiology*; D012189:Retrospective Studies; D012621:Seasons; D013696:Temperature