What Is the Actual Incidence of Peritonitis in Maintenance Peritoneal Dialysis? A Prospective Study

Abstract: Generally, the incidence of peritonitis in maintenance peritoneal dialysis programs is calculated as a percentage of the total number of treatments or as the number of episodes per patient-months. Both statistical methods give the wrong impression that peritonitis is seldom observed. However, peritonitis is still the major and unsolved challenge to successful long-term peritoneal dialysis. The lack of a standard and homogeneous definition of peritonitis is another critical point that prevents a rational interpretation of the published experiences. In the present study, dialysate cell counts of > 1,100 cells/mm³ were assumed to be the first sign of peritoneal infection. As long as more signs and symptoms are required for recognizing peritonitis (fever, abdominal pains, positive cultures), the statistical probability of making such a diagnosis shows the characteristics of a Poisson distribution. It is concluded that in long-term peritoneal dialysis, the currently used statistical methodology for evaluation of the incidence of peritonitis, including the clinical definition of this complication, is misleading. Dialysate cell counts appear to be the more sensitive sign for early diagnosis of peritonitis.