A review of urea and creatinine kinetics in predicting CAPD outcome

The adequacy of the peritoneal dialysis prescription is of great concern. Although the use of urea kinetics has become the standard in hemodialysis, its usefulness in peritoneal dialysis is unclear. It has been suggested that creatinine clearance may correlate with clinical outcome in CAPD but, as with urea kinetics, its predictive value is not established. The efficacy number (EN), which only requires a four hour exchange, was introduced as a simpler approach to creatinine kinetics. These three kinetic models were correlated to clinical outcome in 18 stable CAPD patients over a 12 month study period. The patients were divided into three groups: good (G), intermediate (I), and poor (P) based on uremic symptoms, mortality, hospital days, biochemical indices and the need for transfer to hemodialysis. Both forms of creatinine kinetics (weekly creatinine clearance, EN) were able to differentiate between the G, I, and P outcome groups (P < 0.05). The weekly uea Kt/V was able to differentiate between the G and P groups (P < 0.05) but not between the I and the other two outcome groups. Both urea and creatinine kinetics predict clinical outcome in CAPD. However, creatinine kinetics may be a more sensitive predictor. The efficacy number was just as sensitive as creatinine clearance in predicting clinical outcome yet simpler to gather the data for its calculation.