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ID
Source
Brief title
Health condition
Chronic kidney disease
Sponsors and support
Intervention
Outcome measures
Primary outcome
The difference between measured and estimated dietary sodium, potassium and Na/K ratio intake, using:
- a single 24-hour urine collection
- repeated spot urine collections
Secondary outcome
For the most accurate estimation of dietary sodium, potassium and Na/K ratio intake, we will:
- compare the performance of 1, 3, 5 and 7 consecutive 24-hour urine collections
- compare the performance of 1, 3, 5 and 7 consecutive spot urine collections
- compare the performance of 1, 3, 5 and 7 consecutive spot urine collections with a single and repeated 24-hour urine collection
We will compare the performance of dietary sodium, potassium and Na/K ratio intake estimates based on:
- morning, daytime, pre-night and combined morning + pre-night spot urine collections
- different spot urine equations
Define the potential value of the urine Na/K ratio as compared to separate urine sodium and potassium measurements by comparing discrepancies (%) between:
- measured and estimated sodium intake
- measured and estimated potassium intake
- measured and estimated Na/K ratio
Determine the effects of age, medication use, eGFR and proteinuria on discrepancies (%) between:
- measured and estimated sodium intake
- measured and estimated potassium intake
- measured and estimated Na/K ratio
Investigate the effects of correcting 24-hour sodium and potassium excretion for 24-hour aldosterone and cortisol excretion, by determining:
- estimated sodium and potassium intake by correcting 24-hour urine sodium and potassium excretion for 24-hour urine aldosterone and cortisol excretion
- discrepancy (%) between measured and estimated sodium and potassium intake with and without correction for 24-hour urine aldosterone and cortisol excretion
Background summary
Backgroud
High sodium intake is associated with worse cardiovascular and renal outcomes, whereas the contrary is observed when potassium rich diets are consumed. Because of this, patients with kidney and cardiovascular disease are advised to limit sodium intake to 2 g/d. To monitor sodium intake, patients collect 24-hour urine in which sodium excretion is measured. This method is based on the assumption that 24-hour sodium excretion equals 24-hour sodium intake. Recent studies demonstrated that this assumption is false and that sodium can be stored in and released from a newly discovered skin compartment. The use of 24-hour potassium excretion for estimation of potassium intake, although not commonly used, has also shown to be inaccurate. As a result, dietary advices to patients based on 24-hour urine collections are inadequate. We need improved urine-based methods for estimation of dietary sodium and potassium intake, preferably with limited patient burden.
Design
This is an observational study. Participants with chronic kidney disease will receive a 14-day standardized diet, containing a fixed amount of sodium (157 mmol/day = 3600 mg/day) and potassium (85 mmol/day = 3300 mg/day). During the study all urine will be collected.
Objectives
The primary aim of this study is to assess whether repeated morning, daytime or pre-night spot urine sampling can accurately estimate dietary sodium intake and to determine the number of spot urine collections that are needed. We will assess whether using repeated spot urine collection is superior to using a single 24-hour urine collection in estimating dietary sodium intake. We will also explore this approach for potassium intake. The secondary objective is to define whether the dietary sodium-to-potassium (Na/K) ratio can be more accurately predicted than dietary sodium or potassium intake separately, by measuring the urinary Na/K ratio. If so, we will determine the number of spot and 24-hour urine collections that are needed for accurate estimation of the dietary Na/K ratio. Further, we will assess whether sodium or potassium intake estimation by 24-hour urine collection can be improved when sodium or potassium excretion is corrected for aldosterone and cortisol excretion.
Study objective
We hypothesize that repeated spot urine sampling is non-inferior to a single 24-hour urine collection to estimate 24-hour dietary sodium and potassium intake.
Study design
Day -7, 0, 3, 6, 9, 12, 15, 18; however, study visits are flexible and will be scheduled based on the availability of participants
Intervention
n/a
Inclusion criteria
• 18-80 years
• estimated glomerular filtration rate (eGFR) 15-60 ml/min/1.73m2 as measured with the CKD-EPI equation and/or albuminuria (albumin >30 mg/24h or albumine-creatinine ratio >3 mg/mmol)
Exclusion criteria
• office blood pressure > 180/100 mmHg
• acute kidney injury
• changes in antihypertensive medication in the last 2 months
• use of systemic glucocorticoids
• dialysis treatment or expected initiation of dialysis within 3 months of screening
• (history of) restrictive dietary habits
• eating disorder
• food allergies
Design
Recruitment
IPD sharing statement
Followed up by the following (possibly more current) registration
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Other (possibly less up-to-date) registrations in this register
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In other registers
| Register | ID |
|---|---|
| NTR-new | NL9032 |
| Other | METC AMC : METC 2020_141 |