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.
Design: Retrospective study.
Setting: A single regional dialysis unit in a university teaching hospital.
Patients: 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.