Measurement of continuous ambulatory peritoneal dialysis prescription adherence using a novel approach

Objective:The purpose of the study was to test a novel approach to monitori ng the adherence of continuous ambulatory peritoneal dialysis (CAPD) patien ts to their dialysis prescription. Design: A descriptive observational study was done in which exchange behavi ors were monitored over a 2-week period of time. Setting: Patients were recruited from an outpatient dialysis center. Participants: A convenience sample of patients undergoing CAPD at Piedmont Dialysis Center in Winston-Salem, North Carolina was recruited for the stud y. Of 31 CAPD patients, 20 (64.5%) agreed to participate. Measures: Adherence of CAPD patients to their dialysis prescription was mon itored using daily logs and an electronic monitoring device (the Medication Event Monitoring System, or MEMS; APREX, Menlo Park, California, U.S.A.). Patients recorded in their logs their exchange activities during the P-week observation period. Concurrently, patients were instructed to deposit the pull tab from their dialysate bag into a MEMS bottle immediately after perf orming each exchange. The MEMS bottle was closed with a cap containing a co mputer chip that recorded the date and time each time the bottle was opened . Results: One individual's MEMS device malfunctioned and thus the data prese nted in this report are based upon the remaining 19 patients. A significant discrepancy was found between log data and MEMS data, with MEMS data indic ating a greater number and percentage of missed exchanges. MEMS data indica ted that some patients concentrated their exchange activities during the da y, with shortened dwell times between exchanges. Three indices were develop ed for this study: a measure of the average time spent in noncompliance, an d indices of consistency in the timing of exchanges within and between days . Patients who were defined as consistent had lower scores on the noncompli ance index compared to patients defined as inconsistent (p = 0.015). Conclusions:This study describes a methodology that may be useful in assess ing adherence to the peritoneal dialysis regimen. Of particular significanc e is the ability to assess the timing of exchanges over the course of a day . Clinical implications are limited due to issues of data reliability and v alidity, the short-term nature of the study, the small sample, and the fact that clinical outcomes were not considered in this methodology study. Addi tional research is needed to further develop this data-collection approach.