title: Three Versus 4 Daily Exchanges and Residual Kidney Function Decline in Incident CAPD Patients: A Randomized Controlled Trial.
abstract: BACKGROUND
  Incident patients treated with continuous ambulatory peritoneal dialysis (CAPD) are often prescribed either 3 or 4 exchanges per day. However, the effects on residual kidney function and clinical outcomes of 3 versus 4 exchanges are not known.
  
  
  METHODS
  Prospective, randomized, controlled, open-label study.
  
  
  METHODS
  Incident CAPD patients aged 18 to 80 years with glomerular filtration rates (GFRs; mean of renal urea and creatinine clearance from a 24-hour urine collection) ≥ 2mL/min and urine volume ≥ 500mL/d. Exclusion criteria included refusal for informed consent, history of maintenance hemodialysis therapy or transplantation, or limited life expectancy.
  
  
  METHODS
  24-month intervention with 3- or 4-exchange CAPD using glucose-based peritoneal dialysis fluids.
  
  
  RESULTS
  Primary outcomes were GFR, urine volume, and anuria-free survival. Secondary outcomes included peritonitis, patient survival, and technique survival.
  
  
  RESULTS
  The study recruited 139 patients, 70 in the 3-exchange group and 69 in the 4-exchange group. Baseline body mass indexes were 21.4±3.0 and 21.9±3.2kg/m2for the 3- and 4-exchange groups, respectively (P=0.4). After 24 months, for 3 versus 4 exchanges, GFR (1.6±2.0 vs 1.7±1.9mL/min; P=0.8), urine volume (505±522 vs 474±442mL/d; P=0.8), and anuria-free survival (log-rank test statistic = 0.055; P=0.8) did not differ between groups, but Kt/V (1.95±0.39 vs 2.19±0.48; P=0.03) and ultrafiltration (404±499 vs 742±512mL/d; P=0.004) were lower in the 3-exchange group. The 3-exchange group had nominally longer peritonitis-free survival time (log-rank test statistic = 3.811; P=0.05), and nominally fewer patients had peritonitis in this group, though this was not statistically significant (13% vs 26%; P=0.06). Patient survival (log-rank test statistic = 0.978; P=0.3) and technique survival (log-rank test statistic = 0.347; P=0.6) were similar between groups.
  
  
  CONCLUSIONS
  Single-center design; no formal sample-size calculations.
  
  
  CONCLUSIONS
  In this small trial, CAPD regimens with 3 and 4 exchanges had similar effects on residual GFR, urine volume, and time to anuria. Incremental peritoneal dialysis starts appear safe when patients are monitored.
authors.affiliation: Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; Shanghai Center for Peritoneal Dialysis Research, Shanghai, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; Shanghai Center for Peritoneal Dialysis Research, Shanghai, China. Electronic address: fangwei_sh@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Fang
authors.affiliation: Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; Shanghai Center for Peritoneal Dialysis Research, Shanghai, China.
authors.forename: Aiwu
authors.initials: A
authors.lastname: Lin
authors.affiliation: Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; Shanghai Center for Peritoneal Dialysis Research, Shanghai, China.
authors.forename: Liou
authors.initials: L
authors.lastname: Cao
authors.affiliation: Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; Shanghai Center for Peritoneal Dialysis Research, Shanghai, China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Ni
authors.affiliation: Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; Shanghai Center for Peritoneal Dialysis Research, Shanghai, China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Qian
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001002:Anuria / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory / Q000379:methods*; D011446:Prospective Studies; D015996:Survival Rate; D014563:Urodynamics / Q000502:physiology; D055815:Young Adult
keywords: Continuous ambulatory peritoneal dialysis (CAPD); PD regimen; daily urine volume; diuresis; exchanges; glomerular filtration rate (GFR); patient survival; peritonitis; randomized controlled trial (RCT); residual kidney function (RKF); technique survival; time to anuria