ASIA-PACIFIC CHAPTER NEWSLETTER INTERNATIONAL SOCIETY FOR PERITONEAL DIALYSIS (ISPD)

In Australia, peritonitis is an important cause of technique failure and infectious deaths amongst peritoneal dialysis (PD) patients. The temperature and humidity differences in individual climatic regions may influence the development of PD peritonitis by changing patient behaviour and hygiene, distribution of normal skin flora, organism virulence, and the chance of contamination. Previous studies attempting to demonstrate a relationship between changes in temperature and humidity and the occurrence of PD peritonitis have had conflicting outcomes [1-5]. Those studies have been limited by small patient numbers, single-centre sourcing, retrospective design and a relatively narrow range of temperature and humidity in the studied regions, which were often within one climatic region, thereby possibly underestimating the true effect of climatic variation. Australia is in a unique position to evaluate the impact of climate on PD peritonitis because its land mass encompasses a range of different climatic regions concurrently. We recently conducted an observational study to examine the effect of climatic regional variation on the risk, microbiology, treatment, and clinical outcomes of PD-associated peritonitis in all Australian adult PD patients, as recorded in the Australia and New Zealand Dialysis and Transplantation (ANZDATA) registry [6]. Patients were analysed according to the climatic region in which they resided, based on postal code according to the Köppen classification scheme used by the Australian Bureau of Meteorology (http://www.bom.gov.au). The study included 6610 PD patients, in whom 6213 episodes of peritonitis occurred in 3128 patients (47%, 1-15 episodes per patient). The key findings observed in the study included: 1. Disproportionate distribution of PD patients: The majority of PD patients lived in Temperate regions (65%; reference group), followed by Subtropical (26%), Tropical (6%) and Other climatic regions (3%; Desert or Grassland). 2. Differences in patient characteristics: PD patients from Tropical regions were significantly more likely to be Aboriginal and Torres Strait Islander racial origin (adjusted odds ratio [OR]: 25.9; 95% confidence interval [CI]: 18.7 to 35.9), have lower eGFR at dialysis commencement (OR per mL/min/1.73m2: 0.89; 95% CI: 0.84 to 0.93), be current cigarette smokers (OR: 1.54; 95% CI 1.07 to 2.21), have low transporter status (OR: 2.73; 95% CI: 1.60 to 4.66) and receive dialysis at a medium-large (3rd-quartile) centre (OR: 4.32; 95% CI : 3.33 to 5.60, using largest-centre quartile as a reference). 3. Significantly higher overall peritonitis rate and shorter time to first peritonitis amongst patients living in Tropical regions (hazard ratio: 1.15; 95% CI 1.01 to 1.31 relative to Temperate region reference), even after adjustment for differences in demographic and clinical factors, compared to those living in Temperate, Subtropical or Other climatic regions. 4. Dissimilar microbial profile of peritonitis: Tropical (OR: 2.18; 95% CI 1.22 to 3.90, using Temperate as a reference) and Other climatic regions (Desert and Grassland; OR: 3.46; 95% CI: 1.73 to 6.91) were associated with higher rates of fungal peritonitis, whilst culture-negative peritonitis was significantly less likely to occur in Tropical regions (adjusted OR: 0.42; 95% CI: 0.25 to 0.73). 5. Divergent approach in initiating empiric antibiotics: Patients from Tropical regions were more likely to receive treatment with vancomycin in combination with an aminoglycoside or a 1st-generation cephalosporin in combination with a 3rdor 4th-generation cephalosporin. Moreover, in spite of higher rates of fungal peritonitis, antifungal chemoprophylaxis was less commonly used in Tropical and Other climatic regions than in Subtropical regions. Increased episodes of peritonitis in warmer climatic conditions is biologically plausible because hot and humid climates promote skin perspiration and may influence human behaviour, such that people living in Tropical regions may be more likely to participate in outdoor activities such as swimming in oceans or waterholes. Furthermore, FR OM TH E E DI TO RI AL O FF IC E Dear All,