Sodium intake in Germany estimated from sodium excretion measured in spot urine samples

SummaryBackgroundIn the PATHWAY-2 study of resistant hypertension, spironolactone reduced blood pressure substantially more than conventional antihypertensive drugs. We did three substudies to assess the mechanisms underlying this superiority and the pathogenesis of resistant hypertension.MethodsPATHWAY-2 was a randomised, double-blind crossover trial done at 14 UK primary and secondary care sites in 314 patients with resistant hypertension. Patients were given 12 weeks of once daily treatment with each of placebo, spironolactone 25–50 mg, bisoprolol 5–10 mg, and doxazosin 4–8 mg and the change in home systolic blood pressure was assessed as the primary outcome. In our three substudies, we assessed plasma aldosterone, renin, and aldosterone-to-renin ratio (ARR) as predictors of home systolic blood pressure, and estimated prevalence of primary aldosteronism (substudy 1); assessed the effects of each drug in terms of thoracic fluid index, cardiac index, stroke index, and systemic vascular resistance at seven sites with haemodynamic monitoring facilities (substudy 2); and assessed the effect of amiloride 10–20 mg once daily on clinic systolic blood pressure during an optional 6–12 week open-label runout phase (substudy 3). The PATHWAY-2 trial is registered with EudraCT, number 2008–007149–30, and ClinicalTrials.gov, number NCT02369081.FindingsOf the 314 patients in PATHWAY-2, 269 participated in one or more of the three substudies: 126 in substudy 1, 226 in substudy 2, and 146 in substudy 3. Home systolic blood pressure reduction by spironolactone was predicted by ARR (r2=0·13, p<0·0001) and plasma renin (r2=0·11, p=0·00024). 42 patients had low renin concentrations (predefined as the lowest tertile of plasma renin), of which 31 had a plasma aldosterone concentration greater than the mean value for all 126 patients (250 pmol/L). Thus, 31 (25% [95% CI 17–33]) of 126 patients were deemed to have inappropriately high aldosterone concentrations. Thoracic fluid content was reduced by 6·8% from baseline (95% CI 4·0 to 8·8; p<0·0001) with spironolactone, but not other treatments. Amiloride (10 mg once daily) reduced clinic systolic blood pressure by 20·4 mm Hg (95% CI 18·3–22·5), compared with a reduction of 18·3 mm Hg (16·2–20·5) with spironolactone (25 mg once daily). No serious adverse events were recorded, and adverse symptoms were not systematically recorded after the end of the double-blind treatment. Mean plasma potassium concentrations increased from 4·02 mmol/L (95% CI 3·95–4·08) on placebo to 4·50 (4·44–4·57) on amiloride (p<0·0001).InterpretationOur results suggest that resistant hypertension is commonly a salt-retaining state, most likely due to inappropriate aldosterone secretion. Mineralocorticoid receptor blockade by spironolactone overcomes the salt retention and resistance of hypertension to treatment. Amiloride seems to be as effective an antihypertensive as spironolactone, offering a substitute treatment for resistant hypertension.FundingBritish Heart Foundation and UK National Institute for Health Resea...

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“…Nor was it due to excessive dietary sodium intake as the 24 h urinary sodium was typical of that seen in western Europe. 17 …”

Section: Discussionmentioning

confidence: 99%

Endocrine and haemodynamic changes in resistant hypertension, and blood pressure responses to spironolactone or amiloride: the PATHWAY-2 mechanisms substudies

Williams

MacDonald

Morant

et al. 2018

The Lancet Diabetes & Endocrinology

214

132

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“…The amount of sodium that is excreted throughout the day is assumed to roughly correspond to a person’s daily sodium intake; as such, the amount of sodium measured in the urine constitutes a suitable biomarker to measure sodium intake. Casual urine samples were collected as part of the German Health Interview and Examination Survey for Adults (DEGS1), which was conducted by the Robert Koch Institute between 2008 and 2011 [ 15 ]. The measured sodium concentrations were converted to estimates of daily sodium excretion based on creatinine concentrations [ 15 ].…”

Section: Indicatormentioning

confidence: 99%

Sodium intake in Germany

Klenow¹,

Mensink²

2016

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For many years, a high sodium intake has been discussed as a potential risk factor in the development of hypertension and, consequently, cardiovascular diseases. As part of the German Health Interview and Examination Survey for Adults (DEGS1), which was conducted between 2008 and 2011, sodium excretion in casual urine samples was used as a biomarker to measure sodium intake. DEGS1 observed that the median daily sodium intake of women (3.4 g) as well as men (4.0 g) exceeds the levels recommended by German and international organisations. Among other factors, men’s higher sodium intake could be explained by their higher energy intake. In addition, DEGS1 demonstrates an association between women’s sodium intake and age; however, no equivalent correlation was identified for men. Furthermore, although high socio-economic status is associated with lower sodium intake in men, no comparable correlation was observed among women.

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“…One popular alternative to 24-h U measurement is estimating Na intake from spot-urine collections, which have known specificities and limitations (9)(10)(11)(12)(13)(14) . Different approaches exist as to time of collection, and different population-specific estimating equations have been developed to take into account ethnicity, sex, age, and body weight and height (12,(15)(16)(17)(18) .…”

Section: Introductionmentioning

confidence: 99%

“…However, regular nationwide surveys of 24-h urinary Na and ideally K, iodine and creatinine excretions as well are costly and potentially of low reach due to a perceived high burden in collecting adequate 24-h U specimens. Other countries face the same challenges as periodically discussed within the WHO Action Network on Salt Reduction in the Population in the European Region (ESAN) (8) .One popular alternative to 24-h U measurement is estimating Na intake from spot-urine collections, which have known specificities and limitations (9)(10)(11)(12)(13)(14) . Different approaches exist as to time of collection, and different population-specific estimating equations have been developed to take into account ethnicity, sex, age, and body weight and height (12,(15)(16)(17)(18) .…”

mentioning

confidence: 99%

Validation of salt intake measurements: comparisons of a food record checklist and spot-urine collection to 24-h urine collection

Beer-Borst

Hayoz

Krause

et al. 2022

Public Health Nutr.

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Objective: Monitoring population salt intake is operationally and economically challenging. We explored whether a questionnaire assessment and a prediction of Na intake from spot-urine could replace or complement the recommended measurement of Na in 24-h urine (24-h U). Design: Compare the agreement of a Na-specific food record checklist (FRCL) and a late-afternoon spot-urine measurement (PM-spot) with 24-h U measurement in estimating Na intake at group level. Each participant’s use of these methods extended over 3 d. Agreement was assessed using mean (95 % CI) differences, linear regression models and Bland–Altman plots. Setting: The validation study was part of a 1-year workplace intervention trial to lower salt intake in Switzerland. Participants: Seventy women and 71 men, aged 21–61 years, completed three FRCL, and acceptable PM-spot and 24-h U samples at baseline (April–October 2015). Results: Mean Na intake estimates varied slightly across methods (3·5–3·9 g/d). Mean Na intake differences from 24-h U were 0·2 (95 % CI (0, 0·5)) g/d for FRCL and 0·4 (95 % CI (0·2, 0·6)) g/d for PM-spot. Linear regression models and Bland–Altmann plots more clearly depicted differences by sex and discretionary salt use. Conclusions: Although 24-h U remains the best reference method for monitoring Na intake at the population level, PM-spot and FRCL might be more practical instruments for frequent, periodic Na intake assessments. Population-specific prediction models to estimate 24-h U could be developed and evaluated.

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Sodium intake in Germany estimated from sodium excretion measured in spot urine samples

Cited by 8 publications

References 57 publications

Endocrine and haemodynamic changes in resistant hypertension, and blood pressure responses to spironolactone or amiloride: the PATHWAY-2 mechanisms substudies

Endocrine and haemodynamic changes in resistant hypertension, and blood pressure responses to spironolactone or amiloride: the PATHWAY-2 mechanisms substudies

Sodium intake in Germany

Validation of salt intake measurements: comparisons of a food record checklist and spot-urine collection to 24-h urine collection

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