The clinical features, pathogenesis, management, prognosis, and predictors of symptomatic fluid gain (SFR) were analyzed for 71 episodes occurring in 66 patients on continuous peritoneal dialysis, 94.4% on continuous ambulatory peritoneal dialysis (CAPD) and 5.6% on continuous cycling peritoneal dialysis. Compared with a control group of 149 CAPD patients, the SFR group had a higher percentage of diabetics (64 versus 46%) and a higher frequency of noncompliance with fluid restriction (76 versus 22%), salt restriction (74 versus 23%), and performance of dialysis (30 versus 7%) (all at P < or = 0.015). Peripheral edema (100%), pulmonary congestion (80%), pleural effusions (76%), and systolic (83%) and diastolic (66%) hypertension were the most common manifestations of SFR. The annual hospitalization rate for SFR was 4.1 +/- 5.8 days per patient. SFR resulted in the discontinuation of CAPD in 10 patients and death in 1 patient. Serum sodium concentration was not different between dry and maximal weight in the SFR group. Thirty-eight (58%) of SFR and 61 (41%) of control patients were evaluated by peritoneal equilibration tests (PET). SFR patients had lower PET drain volume (2.08 +/- 0.47 versus 2.54 +/- 0.23 L) and a higher frequency of high peritoneal solute transport (32.2 versus 2.4%). In this group, logistic regression identified dietary noncompliance, low PET drain volume, and young age as independent predictors of SFR. Response to management and preventive measures was inconsistent. The best results were obtained by the use of short dwell exchanges with hypertonic dialysate in compliant patients with high peritoneal solute transport. SFR has serious consequences in CAPD. (ABSTRACT TRUNCATED AT 250 WORDS)