Assessment of Dietary Sodium Intake Using the Scored Salt Questionnaire in Autosomal Dominant Polycystic Kidney Disease.

Annette Wong ,Gopala K Rangan,Helen Coolican,Sayanthooran Saravanabavan,Imad Haloob,Susan Coulshed,David W Johnson,Carmel M Hawley,Kamal Sud,Karthik Kumar,Alexandra Munt,Jun Mai,Jane Holt,Mangalee Fernando,Neil Boudville,Anna Rangan,Simon D Roger,Ashley N Chandra,Sunil V Badve,Maureen Lonergan,Vicente E Torres,Eswari Vilayur,Jennifer Q J Zhang ,Vincent Lee ,Margaret Allman‐Farinelli ,Jared J Grantham ,David C.h Harris

doi:10.3390/nu12113376

Abstract

The excess intake of dietary sodium is a key modifiable factor for reducing disease progression in autosomal dominant polycystic kidney disease (ADPKD). The aim of this study was to test the hypothesis that the scored salt questionnaire (SSQ; a frequency questionnaire of nine sodium-rich food types) is a valid instrument to identify high dietary salt intake in ADPKD. The performance of the SSQ was evaluated in adults with ADPKD with an estimated glomerular filtration rate (eGFR) ≥ 30 mL/min/1.73 m2 during the screening visit of the PREVENT-ADPKD trial. High dietary sodium intake (HSI) was defined by a mean 24-h urinary sodium excretion ≥ 100 mmol/day from two collections. The median 24-h urine sodium excretion was 132 mmol/day (IQR: 112–172 mmol/d) (n = 75; mean age: 44.6 ± 11.5 years old; 53% female), and HSI (86.7% of total) was associated with male gender and higher BMI and systolic blood pressure (p < 0.05). The SSQ score (73 ± 23; mean ± SD) was weakly correlated with log10 24-h urine sodium excretion (r = 0.29, p = 0.01). Receiving operating characteristic analysis showed that the optimal cut-off point in predicting HSI was an SSQ score of 74 (area under the curve 0.79; sensitivity 61.5%; specificity 90.0%; p < 0.01). The evaluation of the SSQ in participants with a BMI ≥ 25 (n = 46) improved the sensitivity (100%) and the specificity (100%). Consumers with an SSQ score ≥ 74 (n = 41) had higher relative percentage intake of processed meats/seafood and flavourings added to cooking (p < 0.05). In conclusion, the SSQ is a valid tool for identifying high dietary salt intake in ADPKD but its value proposition (over 24-h urinary sodium measurement) is that it may provide consumers and their healthcare providers with insight into the potential origin of sodium-rich food sources.

Highlights

Autosomal dominant polycystic kidney disease (ADPKD) is the most common (1:1000) adult-onset genetic chronic kidney disease (CKD) caused by variants in either PKD1, PKD2 or, rarely, other genes [1].The cardinal feature of autosomal dominant polycystic kidney disease (ADPKD) is the formation and growth of multiple kidney cysts, which leads to a fifty percent lifetime risk of developing kidney failure, recurrent episodic kidney pain and hypertension [2,3]
This study has evaluated the performance of a food frequency questionnaire to screen for high dietary salt intake in people with ADPKD
The key findings were: (i) a score of greater than 74 from the scored salt questionnaire (SSQ) predicted high dietary salt intake with a positive predictive value (PPV) of 97.6% and a negative predictive value (NPV) of 26.5%, and both of these parameters improved to 100% in participants who had a body mass index (BMI) ≥ 25; (ii) the intake of specific sodium-rich food groups (Processed meats/seafood and flavourings added in cooking or at the table) made a higher contribution to the SSQ score in participants with an SSQ ≥ 74; and (iii) the 24-h urinary sodium excretion was a burdensome method to assess dietary salt, given that 31.2% of our population made errors during the collection period and had to be excluded from the analysis

Summary

Introduction

Autosomal dominant polycystic kidney disease (ADPKD) is the most common (1:1000) adult-onset genetic chronic kidney disease (CKD) caused by variants in either PKD1, PKD2 or, rarely, other genes [1].The cardinal feature of ADPKD is the formation and growth of multiple kidney cysts, which leads to a fifty percent lifetime risk of developing kidney failure, recurrent episodic kidney pain and hypertension [2,3]. In one of the largest clinical trials conducted in PKD, the HALT Progression of Polycystic Kidney Disease (HALT-PKD) study comprising 1044 adults with ADPKD, high dietary sodium intake was associated with a greater total kidney volume (TKV) growth rate and a steeper decline in estimated glomerular filtration rate (eGFR) [5,6]. Based on these data, as well as the benefits of the Dietary Approaches to. The Consortium for Radiologic Imaging Studies of PKD (CRISP) demonstrated that the annual 24-h urine sodium excretion consistently exceeded 190 mmol/day in North American adults with

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