Development of a 'Phosphate Counting Program' on an iTouch to Simplify Self-management of Dietary Phosphate by Patients With End Stage Renal Disease(ESRD) Treated With Peritoneal Dialysis

Project approach and work plan:

Phase 1: In the week prior to the collection of standard pre-clinic blood work (to include calcium, phosphate, PTH), PD patients will keep a 3-day diary that will include all foods and beverages consumed in addition to the portion sizes. At the time of standard pre-clinic bloodwork collection, patients will perform an adequest. Medication lists will be reviewed for: 1) Proton pump inhibitors/ H2 receptor antagonists 2) 25-hydroxyvitamin D3 and 1,25 dihydroxyvitamin D3 and 3) phosphate binders. Doses taken the week prior to standard pre-clinic blood work when the diet diaries are compiled will be recorded. This information will be used for 2 separate purposes: 1) A list of the foods that are actually being eaten by the PD patients will be generated 2) The 3-day average phosphate content will be estimated from each PD patient's food diaries. A regression equation that predicts serum phosphate concentration taking into account phosphate intake, the amount of phosphate binders taken, the dose of vitamin D, use of proton pump inhibitors/H2 antagonists, dialysis adequacy, and serum PTH concentration will be generated.

Phase 2: An iTouch program will be developed using Phase 1 information to assist patients in meal phosphate counting and appropriate binder selection. Processes used to develop similar programs such as the pilot study in patients with diabetes mellitus will be used. A convenience sample of 10 PD patients will use the iTouch program for one month and document their impressions about ease of use, convenience and applicability to their diet choices. Changes to the program will be incorporated based on the patient's comments and laboratory values. If substantial changes are required, another convenience sample of 10 PD patients will be invited to use the program and provide feedback.

Phase 3: 80 consenting PD patients from the Ottawa Hospital and St. Michael's Hospital (if required) will be randomized to usual care for managing phosphate versus use of the iTouch program for meal phosphate counting and matching binder use. This phase of the trial will last 3 months. As simply recording meal phosphate intake in the iTouch program may have an impact on patient behavior, the control group will be asked to enter this data into the program but no binder therapy information will be provided to the patients. During the course of the study, the dose of vitamin D and PD prescription will be held constant in both groups.

Expected Outcome: