Fluid Intake After Hemodialysis: Investigating the Relationship Between Time and Weight Gain During the Interdialytic Interval

Overview: In this observational study, we will have a sample of approximately 20 patients on chronic thrice weekly HD self-monitor their weight gain and blood pressure during the interdialytic intervals for one week. Demographics, anthropometrics, HD prescription and treatment information will be recorded. Study participants will complete four questionnaires at the first study visit and will then be provided medical grade scales and a blood pressure monitor, and will be asked to prospectively record weight changes and blood pressure at home four times a day for one week using a logbook.

Patients with significant residual urinary volume and diabetes mellitus will not be recruited, the latter to remove the bias of blood glucose in determining osmotic thirst.

Home Body Weight Monitoring Study participants will be asked to perform daily home body weight monitoring for the duration of the whole study with medical grade scales. Study participants will be asked to monitor their body weight four times per day: upon waking up, between 12:00 and 2:00 pm, between 6:00 and 8:00 pm and at bedtime. Participants will be asked to wear similar clothing for all measurements. Monitoring will start after the first HD session of the week until the first HD session of the following week.

Home Blood Pressure Monitoring Study participants will be asked to perform daily home blood pressure monitoring for the duration of the whole study with a validated, automated device. Participants with an arteriovenous fistula or graft will be asked to measure blood pressure on the arm without the arteriovenous fistula or graft. Study participants will be asked to monitor blood pressure four times per day, concomitantly with their body weight. Study participants will be asked to record three consecutive blood pressure measurements in a sitting position, after 5 minutes of rest in a quiet room. Monitoring will start after the first HD session of the week until the first HD session of the following week.

Daily Reminders Study participants will be given the option to receive a daily reminder phone call for the duration of the whole study, to encourage compliance to the self-monitoring procedures and to encourage reproducibility (e.g. by wearing similar clothing at each measurement) to weighing procedures. The phone calls will be made from an in-hospital office phone by either the research coordinators or the Ph.D. student attached to this study, following a script. Participants can decline the option of receiving daily reminders.