Gastrointestinal and pancreatic function in peritoneal dialysis patients: their relationship with malnutrition and peritoneal membrane abnormalities.

BACKGROUND: Malnutrition is frequent in peritoneal dialysis (PD) patients, but the contribution of gastrointestinal (GI) dysfunction has not been well established.

METHODS: We studied GI function in 49 stable PD patients to ascertain its relationship with malnutrition. After an overload fat diet, fecal fat, sugar, starch and nitrogen, intestinal protein permeability (alpha(1)-antitrypsin fecal clearance [C-alpha(1)-AT]), fecal chymotrypsin (CT), GI hormones and gastrin, pepsinogen I and II, cholecystokinin (CCK), gastrin releasing peptide (GRP), and neuropeptide Y (NPY) were measured. Vasoactive intestinal polypeptide (VIP), substance P (SP), and tumor necrosis factor (TNF-alpha) and biochemical nutritional markers were evaluated.

RESULTS: All patients showed high fecal sugar. Elevated fecal nitrogen was found in 21 patients, 6 with high C-alpha(1)-AT. High fecal starch levels appeared in 21, fat in 20, and low fecal CT in 39 patients. These determinations showed inverse relation with nutritional markers. Increased fecal C-alpha(1)-AT values were associated with lower serum albumin. Fecal CT values showed a negative linear correlation with serum albumin and were inversely associated with retinol-binding protein, normalized protein nitrogen appearance, and serum iron. High plasma levels of pancreatic stimulating hormones were found: gastrin, CCK, and VIP. These levels were higher in patients with a worse pancreatic exocrine function. Higher values of other GI hormones, gastrin, pepsinogen I and II, CCK, GRP, and TNF-alpha. Normal concentrations of NPY, VIP, and PS were observed.

CONCLUSION: GI abnormalities (malabsorption, maldigestion, pancreatic dysfunction, and protein losing enteropathy) are present in an important number of PD patients. These features are negatively associated to nutrition.