Predictors of outcome following bacterial peritonitis in peritoneal dialysis

No studies have been done to examine factors that predict the outcome of bacterial peritonitis during peritoneal dialysis (PD), beyond the contribution of the organism causing the peritonitis, concurrent exit-site or tunnel infection, and abdominal catastrophes.

In this study we examined several clinical and laboratory parameters that might predict the outcome of an episode of bacterial peritonitis. Between March 1995 and July 2000, we identified 399 episodes of bacterial peritonitis in 191 patients on dialysis.

There were 260 episodes of gram-positive peritonitis, 99 episodes of gram-negative peritonitis, and 40 episodes of polymicrobial peritonitis. Gram-positive peritonitis had a significantly higher resolution rate than either polymicrobial peritonitis or gram-negative peritonitis. Staphylococcus aureus episodes had poorer resolution than other gram-positive infections. Nonpseudomonal peritonitis had a better outcome than Pseudomonas aeruginosa episodes. Among all the gram-negative infections, Serratia marcescens had the worst outcome. Episodes associated with a purulent exit site had poor outcome only on univariate analysis. For those peritonitis episodes in which the PD fluid cell count was > 100/microL for more than 5 days, the nonresolution rate was 45.6%, compared to a 4.2% nonresolution rate when the cell count returned to 100/microL or less in less than 5 days. Those patients that had a successful outcome had been on continuous ambulatory PD for a significantly shorter period of time than those patients that had nonresolution. The nonresolution rate for those patients that had been on PD for more than 2.4 years was 24.4%, compared to 16.5% for those that had been on PD for less than 2.4 years (p = 0.05).

The duration of PD and the number of days the PD effluent cell count remained > 100/microL were the only factors that independently predicted the outcome of an episode of peritonitis. Caucasians seem to have a higher nonresolution (failure) rate compared to Blacks. Other variables, such as the number of peritonitis episodes before the episode in question, vancomycin-based initial empiric treatment, serum albumin level, total lymphocyte count and initial dialysate white blood cell count, age, sex, diabetes, previous renal transplantation, and the use of steroids did not affect the outcome of peritonitis.