Lab-on-a-chip-based self-monitoring device for dietary Intake of Potassium and Sodium: an observational prospective comparative cohort study

Cardiovascular diseases is the leading cause of death globally. Hypertension is
the biggest risk factor for the development of cardiovascular disease and also
chronic kidney disease. Unfortunately the control rates of hypertension remain
poor, only 33% is adequately controlled. Taking into account the growing
prevalence of hypertension there is much need to improve our treatment
strategies. Lifestyle modification is a crucial part of hypertension treatment.
Dietary adjustments are one of those modifications. This includes for instance
reducing sodium intake and upholding enough potassium rich food consumption.
Current guidelines recommend intake of <6.0 grams of salt (sodium-chloride) a
day. For potassium, >3.5 grams a day for men and >3.1 grams a day for women is
recommended. Average salt consumption in the Netherlands between 2006 and 2015
is still very high: men use on average 9,7 grams a day, women 7,4 grams a day.
Potassium intake is just above the recommended level, with selected population
groups still at risk. The gold standard for determining dietary sodium and
potassium intake consists of 24 hour collection of urine at home, transport to
the hospital, analysis by a clinical chemist and patient feedback by the
treating physician. This method is prone to collection error, cumbersome and
time consuming. It also only shows the dietary estimated intake of sodium and
potassium from 1 day and is therefore not representative of a person*s actual
average intake.
CE-Mate B.V., in cooperation with UMC Utrecht, have developed an innovative
lab-on-a-chip self-test device that uses microchip capillary electrophoresis
(µCE) to measure sodium, potassium and creatinine levels in a single drop of
urine. This can be done at home. These values can be used to estimate past 24
hour dietary sodium and potassium intake. For the first time, this provides
the patient with before absent insightfulness in real time daily dietary intake
of sodium and potassium. Thereby subsequently stimulate lifestyle modification
through self-management and self-empowerment (greater involvement in their own
treatment). The method of self-empowerment is proven to be effective in
stimulating adherence to important lifestyle modifications. In conclusion our
medical validation study aims to investigate the agreement of a new self-test
device to estimate past 24 hour sodium and potassium intake versus the current
gold standard of 24 hour urine collection and analysis.

Primary:
- To investigate the agreement between the lab-on-a-chip Medimate Minilab spot
urine self-monitoring device and 24-hour urine collection for estimating past
24-hour dietary sodium intake for daily single and multiple self-tests by using
the Intersalt, Kawasaki and Tanaka formulae


Secondary:
- To investigate the agreement between the lab-on-a-chip Medimate Minilab spot
urine self-monitoring device and 24-hour urine collection for estimating past
24-hour dietary potassium intake for daily single and multiple self-tests by
using the Intersalt, Kawasaki and Tanaka formulae

- To investigate the agreement between the Medimate Minilab performed multiple
spot urine self-tests and 24-hour urine collection for estimating dietary
sodium weekly average by using the Intersalt, Kawasaki and Tanaka formulae
formula.

- To investigate the agreement between the Medimate Minilab performed multiple
spot urine self-tests and 24-hour urine collection for estimating dietary
potassium weekly average by using the Intersalt, Kawasaki and Tanaka formulae
formula.

- To investigate agreement between the lab-on-a-chip Medimate Minilab spot
urine self-monitoring device and 24-hour urine collection for estimating past
24-hour dietary sodium-to-potassium ratio for single and multiple self-tests

- To Investigate the agreement between the Medimate Minilab performed multiple
spot urine tests and 24-hour urine collection for estimating dietary
sodium-to-potassium ratio weekly average.

Observational prospective comparative cohort study

Risk analyses: low, no further comments

Burden participants:
- test subjects are asked to collect and analyse their own urine samples
participate for 3 weeks and 1 day in total
- in total per test subject: 3 times 24 hour urine collection, 31 times spot
urine collection and analysis.
- time investment: 3x times 24 hour urine collection,31 times, once a day and
every 7 days 4 times a day, 10-15 minute urine sample collection and self
testing. Self testing consists of estimated maximum 3-5 minutes self test
preparations and 8 minute automatic measurement of the Medimate Minilab device.
Measurements will be recorded and stored automatically.
- Urine transport and drop-off at the lobaratory site estimated 1 hour per week
(3 hours in total). Introduction, information and instruction meeting at the
start of the study: 1,5 hour in total.

- Test subjects are asked to uphold a certain diet during 3 weeks. 3 different
diets, 1 per week. 1 week will be liberal (own eating habits), 1 week we will
ask the subjects to eat less than 8 grams of salt a day, 1 week we will ask
them to eat > 12 gram a day. Instructions on how to uphold these diets will be
given during a scheduled introduction meeting. Also test subjects will be given
written instructions how to best adhere to dietary advice, setup in cooperation
with our nutrition and dietetics department.