Association between gastric emptying rate and nutritional status in patients treated with continuous ambulatory peritoneal dialysis

Abstract

Objective: To estimate gastric emptying rate in continuous ambulatory peritoneal dialysis (CAPD) patients, with or without indwelling dialysate, and to evaluate if there is an association between gastric motility and nutritional status. Design: Single-center cross-sectional study. Setting: Peritoneal Dialysis Unit, Medical Faculty, Jagiellonian University Hospital, Krakow, Poland. Patients and Methods: 20 end-stage renal disease patients [11 F, 9 M; mean age 50.1 ± 11 years; treated with CAPD for median 13.5 (2 - 61) months] were studied. All patients were nondiabetic and had no comorbidity that might influence gastric motility; nor were they receiving any prokinetic drugs. Gastric emptying rate was estimated with dynamic abdominal scintigraphy, started immediately after complete ingestion of a standard 200-kcal solid meal injected with 99mTc-labeled colloid, activity 40 MBq. Scintigraphy was performed at the rate of 23 images in 4-minute intervals for 92 minutes. Two consecutive procedures - with and without PD fluid - were performed at weekly intervals. As nutritional parameters, protein catabolic rate (PCR) and lean body mass (LBM) (based on urea and creatinine kinetics, respectively), body mass index (BMI), and serum albumin were measured. Results: All analyzed gastric emptying parameters, measured with or without dialysis fluid, were markedly prolonged in patients compared to values accepted as normal in the local scintigraphy unit. Gastric emptying half-time (T1/2) and percent of initial activity in minute 46 and in minute 92 were 60.5 ± 25.0 minutes, 57.19% ± 17.5%, and 33.8% ± 20.9% with a full peritoneal cavity, and 63.9 ± 28.2 minutes, 59.1% ± 23.9%, and 33.9% ± 24.3% with an empty peritoneal cavity. The T1/2 and percent of initial activity after 46 and 92 minutes for healthy subjects were 39 ± 9 minutes, 45% ± 11%, and 15% ± 6%, respectively. T1/2 without dialysis fluid revealed a negative correlation with LBM and BMI values (r = -0.5, p < 0.05, and r = -0.56, p < 0.01; respectively). Patients with dialysate-free T1/2 > 40 minutes were characterized by significantly lower serum albumin level compared to subjects with T1/2 < 40 minutes (39.2 ± 2.9 vs 42.9 ± 3.6 g/L, p < 0.05). The values of all gastric emptying parameters measured for an empty abdomen were prolonged in subjects with BMI < 25 kg/m2. No difference was found between patients with and without PD fluid. Conclusions: Gastric emptying is markedly impaired in CAPD patients compared to healthy subjects. However, the presence of dialysate does not influence it significantly. Gastric emptying rate was negatively associated with the nutritional status of treated subjects. This association can be demonstrated when gastric motility is measured with an empty peritoneal cavity.