Culture-negative peritonitis in peritoneal dialysis patients in Australia: predictors, treatment, and outcomes in 435 cases

Background: Reports of culture-negative peritoneal dialysis (PD)-associated peritonitis have been sparse, conflicting, and limited to small single-center studies. The aim of this investigation is to examine the frequency, predictors, treatment, and outcomes of culture-negative PD-associated peritonitis.

Study design: Observational cohort study using Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) data.

Setting & participants: All Australian PD patients between October 1, 2003, and December 31, 2006.

Predictors: Demographic, clinical, and facility variables.

Outcomes & measurements: Culture-negative PD-associated peritonitis occurrence, relapse, hospitalization, catheter removal, hemodialysis transfer, and death.

Results: Of 4,675 patients who received PD in Australia during the study period, 435 episodes of culture-negative peritonitis occurred in 361 individuals. Culture-negative peritonitis was not associated with demographic or clinical variables. A history of previous antibiotic treatment for peritonitis was more common with culture-negative than culture-positive peritonitis (42% vs 35%; P = 0.01). Compared with culture-positive peritonitis, culture-negative peritonitis was significantly more likely to be cured using antibiotics alone (77% vs 66%; P < 0.001) and less likely to be complicated by hospitalization (60% vs 71%; P < 0.001), catheter removal (12% vs 23%; P < 0.001), permanent hemodialysis therapy transfer (10% vs 19%; P < 0.001), or death (1% vs 2.5%; P = 0.04). Relapse rates were similar between the 2 groups. Patients with relapsed culture-negative peritonitis were more likely to have their catheters removed (29% vs 10% [P < 0.001]; OR, 3.83; 95% CI, 2.00-7.32). Administration of vancomycin or cephalosporin in the initial empiric antibiotic regimen and the timing of catheter removal were not significantly associated with clinical outcomes.

Limitations: Limited covariate adjustment. Residual confounding and coding bias could not be excluded.

Conclusions: Culture-negative peritonitis is a common complication with a relatively benign outcome. A history of previous antibiotic treatment is a significant risk factor for this condition.