The efficacy number as a predictor of morbidity and mortality in peritoneal dialysis patients

Abstract

The efficacy number has been proposed as a predictor of clinical outcome in patients on chronic ambulatory peritoneal dialysis (CARD). The usefulness of this parameter in a large group of CARD patients was analyzed. Forty-five patients who have received chronic CARD therapy for at least 1 yr were included in the study. The efficacy number was compared with outcome as defined by mortality and days of hospitalization. Other demographic and laboratory parameters, including gender; race; presence of diabetes; serum albumin, serum creatinine, and BUN levels; and measures of peritoneal transport, including dialysate-to-plasma creatinine and dialysate-to-plasma urea ratios, were also assessed for their role in predicting outcome. Laboratory values were obtained at the initiation of CARD and at 12 months after the start of CARD. By univariate analysis, a low 12-month serum albumin level was the best predictor of mortality (P < 0.005), followed by a high 12-month efficacy number (P < 0.05). After adjusting for age and the presence of diabetes, these two variables remained the best predictors of mortality (P < 0.08 and < 0.09, respectively). A low initial serum albumin level was also a strong predictor of mortality (P < 0.09). By univariate analysis, the best predictor of hospitalization was a low serum albumin level obtained either initially or at 12 months (P < 0.005 for both time periods). After adjusting for age and the presence of diabetes, the 12-month serum albumin level remained a significant predictor of hospitalization (P < 0.03), whereas efficacy number was not a strong predictor (P = 0.27). In addition, there were statistically significant positive correlations between days of hospitalization and both efficacy number and serum glucose and significant negative correlations between days of hospitalization and both serum albumin and serum creatinine. In conclusion, a low initial or 12-month serum albumin level is a strong predictor of both mortality and hospitalizations. The results on efficacy number presented here are the opposite of those of others because it was observed in this study that a high 12-month efficacy number was almost as strong a predictor of mortality as a low serum albumin level. Further studies are required to determine the usefulness of the efficacy number in predicting outcome in CAPD patients.