Impact of Dialysis Adequacy on the Mortality and Morbidity of Anuric Chinese Patients Receiving Continuous Ambulatory Peritoneal Dialysis CHEUK-CHUN SZETO, TERESA YUK-HWA WONG, KAI-MING CHOW, CHI-BON LEUNG, MAN-CHING LAW, ANGELA YEE-MOON WANG, SIU-FAI LUI, and PHILIP KAM-TAO LI Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China. Abstract. Dialysis adequacy has a major impact on the outcome of continuous ambulatory peritoneal dialysis (CAPD) patients. However, most studies on peritoneal dialysis adequacy have focused on patients with significant residual renal function. The present study examined the effect of dialysis adequacy on anuric CAPD patients. A single-center prospective observa- tional study on 140 anuric CAPD patients was performed. These patients were followed for 22.0  11.9 mo. Dialysis adequacy and nutritional indices, including Kt/V, creatinine clearance (CCr), protein equivalent nitrogen appearance, per- centage of lean body mass, and serum albumin level were monitored. Clinical outcomes included actuarial patient sur- vival, technique survival, and duration of hospitalization. In the study population, 64 were male, 36 (25.7%) were diabetic, and 59 (42.1%) were treated with 6 L exchanges per day. The body weight was 59.2  10.2 kg. Average Kt/V was 1.72  0.31, and CCr was 43.7  11.5 L/wk per 1.73m 2 . Two-yr patient survival was 68.8%, and technique survival was 61.4%. Mul- tivariate analysis showed that DM, duration of dialysis before enrollment, serum albumin, and index of dialysis adequacy (Kt/V or CCr) were independent factors of both patient sur- vival and technique survival. It was estimated that for two patients who differed only in weekly Kt/V, a 0.1 higher value was associated with a 6% decrease in the RR of death (P  0.05; 95% confidence interval, 0.92 to 0.99). Serum albumin and CCr were the only independent factors that predicted hospitalization. It was found that even when there is no resid- ual renal function, higher dialysis dosage is associated with better actuarial patient survival, better technique survival, and shorter hospitalization. Dialysis adequacy has a significant impact on the clinical outcome of CAPD patients, and the beneficial effect is preserved in anuric patients as well as in an ethnic group that has a low overall mortality. Continuous ambulatory peritoneal dialysis (CAPD) is the treat- ment modality of 14% of the world’s dialysis population (1). The adequacy of peritoneal dialysis has a profound impact on mortality and morbidity of CAPD patients (2– 6). Although Chinese dialysis patients have better overall outcome (7,8), dialysis adequacy remains an independent predictor of mortal- ity and morbidity of CAPD patients in this ethnic group (9). However, most studies on peritoneal dialysis adequacy have focused on patients with significant residual renal function. In the CANUSA study, which enrolled only new CAPD patients, nutritional parameters actually worsen after the first 6 mo of the study period, probably secondary to gradual decline of residual renal function (10). The maintenance of adequate dialysis is challenging for patients with little urine output; utilization of higher daily exchange volume becomes inevita- ble. Although renal and peritoneal clearances have often been considered equivalent, this assumption has never been proved (11–13). Previous studies from our group suggested that this assumption might not be valid (9,14). The independent effect of peritoneal clearance on patient outcome can be examined in anuric CAPD patients. Neverthe- less, this approach is practically difficult in most countries because hemodialysis is a readily available alternative for end-stage renal disease (ESRD) patients. Conversely, CAPD is the first-line renal replacement therapy for all ESRD patients in our locality (8). Patients are switched to long-term hemodial- ysis only when they have ultrafiltration failure or peritoneal sclerosis. Although this policy may not be ideal, it provides an excellent opportunity for us to examine the effect of dialysis adequacy on the clinical outcome of a large unselected group of anuric CAPD patients. Materials and Methods Patient Selection We enrolled 140 anuric CAPD patients of our center from Sep- tember 1995 to December 1998. Anuria was defined as no appreciable urine output. Forty-four patients (31.4%) had been participants of our Received February 23, 2000. Accepted May 30, 2000. Correspondence to Dr. Cheuk-Chun Szeto, Department of Medicine & Ther- apeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China. Phone: 852-2632-3173; Fax: 852-2637-3852; E-mail: ccszeto@cuhk.edu.hk 1046-6673/1202-0355 Journal of the American Society of Nephrology Copyright © 2001 by the American Society of Nephrology J Am Soc Nephrol 12: 355–360, 2001