Changes in peritoneal membrane transport rates in patients on long term CAPD

Peritoneal equilibration tests (PET's) are a simple means of monitoring peritoneal membrane function in C.A.P.D. patients. Findings on initial testing have been proposed as having prognostic value for a patient's course on peritoneal dialysis. 177 serial P.E.T.'s were performed in 49 patients at six monthly intervals using a 2 litre 4.25% dextrose exchange and a four hour dwell and equilibration ratios were calculated for urea (D/P U), creatinine (D/P C) and glucose (D/Do G). Alterations in equilibration ratios with time were not significant in the group as a whole. However, a subgroup of 12 patients was identified in whom there were significant increases in D/P U (p .02) and in D/P C (p .003) and decreases in D/Do G (p .025) between zero and 18 months. A subgroup of five patients in whom D/P U decreased significantly (p .05) was also identified. These subgroups did not differ significantly in clinical characteristics although peritonitis was more frequent in the group with increasing transport. As results of P.E.T.'s alter with time in many patients prognostication based on initial values only may not be valid.