Peritoneal dialysate white cell count predicts outcome of peritonitis treatment

Chow KM et al. (2006) Predictive value of dialysate cell counts in peritonitis complicating peritoneal dialysis. Clin J Am Soc Nephrol 1: 768–773

Dialysis-related peritonitis often results in death and catheter loss. In accordance with current guidelines, patients are administered empiric therapy before the causative organism has been identified. Early assessment of treatment response could enable beneficial changes in antimicrobial therapy to be made. Through a retrospective analysis of 565 consecutive episodes of peritonitis complicating peritoneal dialysis in 280 patients, Chow et al. have identified peritoneal dialysate white blood cell count as an accurate early predictor of treatment outcome.

Several factors were predictive of treatment failure, including diabetes, duration of peritoneal dialysis before peritonitis onset, and type of causative organism. Peritoneal dialysate total white cell count on the third day following diagnosis of peritonitis, however, was the most significant indicator (P <0.0001); patients with a count ≥1,090 mm³ on day 3 had a ninefold increased risk of catheter loss or peritonitis-related death, independent of other factors. These findings were confirmed in a separate validation cohort of 217 peritonitis episodes.

Peritoneal dialysate white blood cell count is readily obtainable and is associated with low cost. Chow et al. recommend that the measurement be routinely taken on day 3 following diagnosis, at which point changing the treatment strategy should be effective. It remains to be determined whether aggressive intervention in response to a high dialysate white blood cell count does indeed bring clinical benefit.