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.
Scored Sodium Questionnaire Dietary sodium intake will be estimated with the Scored
Sodium Questionnaire (SSQ)12 on the first study visit, a 10-item food frequency
questionnaire to screen for high sodium intake in CKD. A cut-off value of 65 will be used
to identify patients with high sodium intake.
Dialysis Thirst Inventory The Dialysis Thirst Inventory (DTI) is a questionnaire
developed by Bots et al.13 It is a seven items questionnaire that quantifies the
perception of thirst. Each item has a five-point Likert type scale (never = 1, to very
often = 5). The scores are summed and provide a DTI score ranging from 7 (no thirst) to
35 (very thirsty). The items are the following: (1) Thirst is a problem for me. (2) I am
thirsty during the day. (3) I am thirsty during the night. (4) My social life is
influenced because of my thirst feelings; (5) I'm thirsty before dialysis. (6) I am
thirsty during dialysis. (7) I am thirsty after dialysis. This questionnaire will be
administered on the first study visit.
Xerostomia Inventory The validated Xerostomia Inventory (XI) consists of 11 items, each
with a five-point Likert type scale (never=1, to very often=5) to evaluate xerostomia,
that is a feeling of dry mouth.14 Examples of items from the XI are "My mouth feels
dry...", "I have difficulty in eating dry foods..." and "I sip liquids to aid in
swallowing food." The responses to the 11 items result in an individual XI score for each
participant that can range from 11 (no dry mouth) to 55 (extremely dry mouth). This
questionnaire will be administered on the first study visit.
Minutes to Recovery after HD This is a clinically validated, simple question, as
published by Lindsay et al.15 The question is: "How long does it take you to recover from
a dialysis session?", to which participants are free to respond by providing exact times
to approximate estimates such as "half a day". The final answer will be converted to
minutes for analysis purposes. Responses to this question were reported to be highly
reproducible over time and correlated with several quality of life questionnaires, mainly
pointing towards physical wellbeing rather than mental health. Furthermore, this measure
was sensitive enough to show differences in recovery time between different HD
prescriptions (standard vs daily vs nocturnal HD). This question will be administered on
the first study visit.
Urine collection When applicable, participants will be asked to collect and record their
urine volume on the last day of the long interdialytic interval (Sunday for
Monday-Wednesday-Friday patients, Monday for Tuesday-Thursday-Saturday patients).
Participants will be provided a disposable urine collection container for this purpose.
After completing the collection and recording the total urine volume, the participants
will dispose of the urine themselves.
Concomitant Medications Throughout the study, all participants will continue to take all
medications as prescribed by their clinical care team and will follow any changes to
their medication as seen fit.