Seasonal variation in peritoneal dialysis-associated peritonitis: a multi-centre registry study.

BACKGROUND The role of seasonal variation in peritoneal dialysis (PD)-related peritonitis has been limited to a few small single-centre studies. METHODS Using all 6610 Australian patients receiving PD between 1 October 2003 and 31 December 2008, we evaluated the influence of seasons on peritonitis rates (Poisson regression) and outcomes (multivariable logistic regression). RESULTS The overall rate of peritonitis was 0.59 episodes per patient-year of treatment. Using winter as the reference season, the peritonitis incidence rate ratios (95% confidence interval) for summer, autumn and spring were 1.02 (0.95-1.09), 1.01 (0.94-1.08) and 0.99 (0.92-1.06), respectively. Significant seasonal variations were observed in the rates of peritonitis caused by coagulase-negative Staphylococci (spring and summer peaks), corynebacteria (winter peak) and Gram-negative organisms (summer and autumn peaks). There were trends to seasonal variations in fungal peritonitis (summer and autumn peaks) and pseudomonas peritonitis (summer peak). No significant seasonal variations were observed for other organisms. Peritonitis outcomes did not significantly vary according to season. CONCLUSIONS Seasonal variation has no appreciable influence on overall PD peritonitis rates or clinical outcomes. Nevertheless, significant seasonal variations were observed in the rates of peritonitis due to specific microorganisms, which may allow institutions to more precisely target infection control strategies prior to higher risk seasons.