Alwyn Todd

Dietary salt loading impairs arterial vascular reactivity

BACKGROUND Studies of sodium have shown improvements in vascular function and blood pressure (BP). The effect of chronic sodium loading from a low-sodium diet to a Western diet on vascular function and BP has been less well studied. OBJECTIVE The objective was to examine the effects of dietary salt intake on vascular function and BP. DESIGN Thirty-five hypertensive volunteers met the inclusion criteria. After a 2-wk run-in with a low-sodium diet (60 mmol/d), the participants maintained their diets and were randomly assigned to receive sequentially 1 of 3 interventions for 4 wk, with a 2-wk washout between interventions: sodium-free tomato juice (A), tomato juice containing 90 mmol Na (B), and tomato juice containing 140 mmol Na (C). The outcomes were changes in pulse wave velocity (PWV), systolic BP (SBP), and diastolic BP (DBP). RESULTS The difference in PWV between interventions B and A was 0.39 m/s (95% CI: 0.18, 0.60 m/s; P < or = 0.001) and between C and A was 0.35 m/s (95% CI: 0.13, 0.57 m/s; P < or = 0.01). Differences in SBP and DBP between interventions B and A were 4.4 mm Hg (95% CI: 1.2, 7.8 mm Hg; P < or = 0.01) and 2.4 mm Hg (95% CI: 0.8, 4.1 mm Hg; P < or = 0.001), respectively, and between interventions C and A were 5.6 mm Hg (95% CI: 2.7, 8.4 mm Hg; P < or = 0.01) and 3.3 mm Hg (95% CI: 1.5, 5.0 mm Hg; P < or = 0.001), respectively. Changes in PWV correlated with changes in SBP (r = 0.52) and DBP (r = 0.58). CONCLUSIONS Dietary salt loading produced significant increases in PWV and BP in hypertensive volunteers. Correlations between BP and PWV suggest that salt loading may have a BP-independent effect on vascular wall function. This further supports the importance of dietary sodium restriction in the management of hypertension. This trial was registered with the Australian and New Zealand Clinical Trials Registry as ACTRN12609000161224.

Dietary sodium loading in normotensive healthy volunteers does not increase arterial vascular reactivity or blood pressure

Background:  Studies of dietary sodium on vascular function and blood pressure in normotensive volunteers have shown conflicting results. There are very limited data available on the effect of chronic sodium loading from a low‐sodium diet to a high‐sodium diet on vascular function and blood pressure in normotensive volunteers.

Simple Nutrition Screening Tool for Pediatric Inpatients

BACKGROUND Pediatric nutrition risk screening tools are not routinely implemented throughout many hospitals, despite prevalence studies demonstrating malnutrition is common in hospitalized children. Existing tools lack the simplicity of those used to assess nutrition risk in the adult population. This study reports the accuracy of a new, quick, and simple pediatric nutrition screening tool (PNST) designed to be used for pediatric inpatients. MATERIALS AND METHODS The pediatric Subjective Global Nutrition Assessment (SGNA) and anthropometric measures were used to develop and assess the validity of 4 simple nutrition screening questions comprising the PNST. Participants were pediatric inpatients in 2 tertiary pediatric hospitals and 1 regional hospital. RESULTS Two affirmative answers to the PNST questions were found to maximize the specificity and sensitivity to the pediatric SGNA and body mass index (BMI) z scores for malnutrition in 295 patients. The PNST identified 37.6% of patients as being at nutrition risk, whereas the pediatric SGNA identified 34.2%. The sensitivity and specificity of the PNST compared with the pediatric SGNA were 77.8% and 82.1%, respectively. The sensitivity of the PNST at detecting patients with a BMI z score of less than -2 was 89.3%, and the specificity was 66.2%. Both the PNST and pediatric SGNA were relatively poor at detecting patients who were stunted or overweight, with the sensitivity and specificity being less than 69%. CONCLUSION The PNST provides a sensitive, valid, and simpler alternative to existing pediatric nutrition screening tools such as Screening Tool for the Assessment of Malnutrition in Pediatrics (STAMP), Screening Tool Risk on Nutritional status and Growth (STRONGkids), and Paediatric Yorkhill Malnutrition Score (PYMS) to ensure the early detection of hospitalized children at nutrition risk.

Nutritional status of haemodialysis patients: Comparison of Australian cohorts of Aboriginal and European descent

It is not known whether nutritional status differs between Australian Aboriginal and non Aboriginal haemodialysis subjects. The aim of this study was to investigate the nutritional status of Australian Aboriginal and non‐Aboriginal haemodialysis subjects at satellite dialysis centres.

Development and pilot testing of a parent-reported health-related quality of life measure for children on the ketogenic diet: The KetoQoL

AIM The aim of the present study was to develop a parent-reported tool that will measure health-related quality of life (HRQoL) in children following ketogenic diet (KD) therapies for refractory epilepsy once it has been pilot tested and analysed. METHODS Parents of children following KD therapies for epilepsy were recruited through a public hospital in Queensland, Australia, in 2012 and 2014. Qualitative semistructured interviews were conducted in 2012 with 13 parents who described changes seen in their childs HRQoL while on the KD. A quality of life tool (QoL) was developed by adapting the Quality of Life in Childhood Epilepsy tool based on results and themes analysed from the interviews. The KetoQoL was pilot tested with 18 parents recruited in 2014. Interrelationships between variables and questions were explored with exploratory factor analysis (EFA) to determine which questions had the greatest effect on QoL. RESULTS The first iteration of the KetoQoL consisted of five main domains: physical, cognitive, social, intrapersonal and effects on the family. The domains were subdivided into 18 variables, totalling 54 items. EFA demonstrated that items from the physical and effects on the family domains had the greatest effect on QoL. CONCLUSIONS KetoQoL is an HRQoL tool developed using a range of methods and assessed for both face and content validity. Further testing of KetoQoL is required to refine and confirm the factors. This work will enhance the evaluation of treatment effectiveness in children with epilepsy following the KD.

The effect of dietary sodium modification on blood pressure in studies of subjects with systolic blood pressure less than 140mmHg: a systematic review protocol

Review question/objective The objective of this review is to establish the effect of modifying dietary sodium intake in normotensive subjects. More specifically, the objectives are to identify the effect of reducing or increasing sodium intake on blood pressure in normotensive subjects with systolic blood pressure (SBP) <140mmHg, and the effect of sodium reduction or supplementation on arterial function in subjects with baseline SBP <140mmHg. Background The pressure‐natriuresis relationship that was first described by Guyton1 proposes a link between dietary sodium intake and renal sodium handling. Specifically, the hypothesis states that in a normal individual, consumption of a dietary sodium load will elicit a transient rise in blood pressure that stimulates the kidney to excrete sodium. The kidney will excrete excess sodium leading to restoration of normal blood pressure. This hypothesis explains how blood pressure is maintained over the longer term even though most individuals report day‐to‐day variation in sodium intake.1,2 Following this hypothesis, intervention studies in normotensive subjects may be expected to observe a small amount of variation in blood pressure with changes to dietary sodium intake, but this variation should be small enough to be considered clinically irrelevant. Intervention studies examining the effect of dietary sodium have reported a range of different responses from significant changes,3,4 to mild, to moderate effects on blood pressure to no effect at all.5,6 Normotensive studies that report blood pressure changes over the long‐term have previously documented changes in systolic blood pressure (SBP) ranging from ‐1mmHg7 to increases of 8.2mmHg.4 Previous systematic reviews of blood pressure response to dietary sodium restriction have used Cochrane Collaboration methods.8‐10 One such systematic review9 has been cited over 370 times, and has been used in the development of dietary guidelines.11 Two of these reviews attempted to conduct meta‐analysis by dividing subjects into normotensive and hypertensive sub‐groups.8,9 Both reviews failed to specify methods for determining whether studies recruited hypertensive or normotensive subjects and included some studies in the normotensive analyses with subjects who had baseline blood pressures above 140mmHg. Due to this, a wide range of baseline blood pressure readings and responses can be observed in normotensive analyses, which is inconsistent with Guytons pressure natriuresis hypothesis. Therefore, the validity of the findings for blood pressure changes in healthy normotensive individuals in these analyses is limited in that the majority of the included studies recruited subjects with SBP above 140mmHg.4,12‐16 Subjects with hypertension (SBP >140mmHg) have been shown to respond differently to dietary sodium and hence inclusion of these studies in previous normotensive analyses may have skewed the results.9 These analyses in “normotensive” populations could be improved if studies that recruited subjects with SBP >140mmHg were excluded. As well as examining blood pressure, a number of intervention studies have investigated the effects of dietary sodium intake on arterial function and found that these effects may be, at least partly, independent of blood pressure.17,18 As these effects may be key in extending our understanding of sodium intake and disease risk, they form part of the bigger picture for dietary sodium intake and chronic disease risk. It is therefore important to consider data on arterial function such as pulse wave analysis, pulse wave velocity, and flow mediated dilation in future meta‐analyses of sodium restriction. There is enough evidence from normotensive studies conducted in subjects with SBP≤140mmHg to conduct a separate investigation of the effects on blood pressure and arterial function. This systematic review will consider the evidence for long‐term dietary sodium restriction in subjects with SBP <140mmHg on arterial function.

Diabetes-Specific Formulae Versus Standard Formulae as Enteral Nutrition to Treat Hyperglycemia in Critically Ill Patients: Protocol for a Randomized Controlled Feasibility Trial

Background During critical illness, hyperglycemia is prevalent and is associated with adverse outcomes. While treating hyperglycemia with insulin reduces morbidity and mortality, it increases glycemic variability and hypoglycemia risk, both of which have been associated with an increase in mortality. Therefore, other interventions which improve glycemic control, without these complications should be explored. Nutrition forms part of standard care, but the carbohydrate load of these formulations has the potential to exacerbate hyperglycemia. Specific diabetic-formulae with a lesser proportion of carbohydrate are available, and these formulae are postulated to limit glycemic excursions and reduce patients’ requirements for exogenous insulin. Objective The primary outcome of this prospective, blinded, single center, randomized controlled trial is to determine whether a diabetes-specific formula reduces exogenous insulin administration. Key secondary outcomes include the feasibility of study processes as well as glycemic variability. Methods Critically ill patients will be eligible if insulin is administered whilst receiving exclusively liquid enteral nutrition. Participants will be randomized to receive a control formula, or a diabetes-specific, low glycemic index, low in carbohydrate study formula. Additionally, a third group of patients will receive a second diabetes-specific, low glycemic index study formula, as part of a sub-study to evaluate its effect on biomarkers. This intervention group (n=12) will form part of recruitment to a nested cohort study with blood and urine samples collected at randomization and 48 hours later for the first 12 participants in each group with a secondary objective of exploring the metabolic implications of a change in nutrition formula. Data on relevant medication and infusions, nutrition provision and glucose control will be collected to a maximum of 48 hours post randomization. Baseline patient characteristics and anthropometric measures will be recorded. A 28-day phone follow-up will explore weight and appetite changes as well as blood glucose control pre and post intensive care unit (ICU) discharge. Results Recruitment commenced in February 2015 with an estimated completion date for data collection by May 2018. Results are expected to be available late 2018. Conclusions This feasibility study of the effect of diabetes-specific formulae on the administration of insulin in critically ill patients and will inform the design of a larger, multi-center trial. Trial Registration Australian New Zealand Clinical Trial Registry (ANZCTR):12614000166673; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12614000166673 (Archived by WebCite at http://www.webcitation.org/6xs0phrVu)

Nutritional assessment and status of hospitalized infants

Objectives: Malnutrition during infancy has long-term adverse consequences for both physical and psychological development. Early detection of malnutrition among hospitalized infants is essential to provide optimal nutrition support. The primary aim of the present study was to investigate the nutritional status of hospitalized infants using 2 methods: the Subjective Global Nutritional Assessment (SGNA) and anthropometric measurement. We also investigated diagnostic category associated with nutritional status, the mean anthropometric z scores, and explored the association between malnutrition and nutrition focused variables. Methods: Nutritional status of 110 hospitalized infants ages 31 days to 12 months was investigated using the SGNA and anthropometric measurements converted to z scores. Results: Utilizing the SGNA, 78 (70.9%) infants were classified as having normal nutritional status, 30 (27.3%) were moderately malnourished, and 2 (1.8%) were severely malnourished. The proportion of infants with acute malnutrition (weight-for-length z score <−2) was 16.4%, and chronic malnutrition (length-for-age z score <−2) was 3.6%. The mean anthropometric z scores of infants were significantly lower in infants identified as moderately and severely malnourished using the SGNA. Decrease in serial weight (odds ratio [OR] 44.4; 95% confidence interval [CI]: 4.3–451.5), having prolonged gastrointestinal symptoms (OR 18.8; 95% CI: 1.5–234.7), and reduced nutrition-related functional capacity (OR 27.6; 95% CI 2.5–301.7) were associated with malnutrition after adjusting for sex, age, and length of hospital stay. Conclusions: Regardless of the method applied, cases of malnutrition amongst hospitalized infants were identified. The SGNA is a comprehensive approach to identifying malnutrition in hospitalized infants.

Dietary sodium modifies serum uric acid concentrations in humans

BACKGROUND Subjects with hypertension are frequently obese or insulin resistant, both conditions in which hyperuricemia is common. Obese and insulin-resistant subjects are also known to have blood pressure that is more sensitive to changes in dietary sodium intake. Whether hyperuricemia is a resulting consequence, moderating or contributing factor to the development of hypertension has not been fully evaluated and very few studies have reported interactions between sodium intake and serum uric acid. METHODS We performed further analysis of our randomized controlled clinical trials (Australian New Zealand Clinical Trials Registry #12609000161224 and #12609000292279) designed to assess the effects of modifying sodium intake on concentrations of serum markers, including uric acid. Uric acid and other variables (including blood pressure, renin, and aldosterone) were measured at baseline and 4 weeks following the commencement of low (60 mmol/day), moderate (150 mmol/day), and high (200-250 mmol/day) dietary sodium intake. RESULTS The median aldosterone-to-renin ratio was 1.90 [pg/ml]/[pg/ml] (range 0.10-11.04). Serum uric acid fell significantly in both the moderate and high interventions compared to the low sodium intervention. This pattern of response occurred when all subjects were analyzed, and when normotensive or hypertensive subjects were analyzed alone. CONCLUSIONS Although previously reported in hypertensive subjects, these data provide evidence in normotensive subjects of an interaction between dietary sodium intake and serum uric acid. As this interaction is present in the absence of hypertension, it is possible it could play a role in hypertension development, and will need to be considered in future trials of dietary sodium intake. CLINICAL TRIALS REGISTRATION The trials were registered with the Australian and New Zealand Clinical Trials Registry as ACTRN12609000161224 and ACTRN1260.

The effect of dietary sodium modification on blood pressure in adults with systolic blood pressure less than 140 mmHg: a systematic review.

BackgroundModifying dietary sodium intake is a cornerstone of diet advice for lowering blood pressure (BP) under the assumption that it is protective against cardiovascular disease. Previous meta-analyses of normotensive participants have not excluded all studies that recruited participants with systolic blood pressure (SBP) > 140 mmHg, which greatly hinders generalization to the wider normotensive population. ObjectivesThe objective of this review was to identify the effectiveness of reducing or increasing sodium intake on BP in normotensive participants with SBP ⩽ 140 mmHg. Inclusion criteria Types of participantsThis review considered studies on adult participants (≥18 years) with SBP ⩽ 140 mmHg. Studies on pregnant women or patients prescribed antihypertensive or vasoactive medications were excluded. Types of interventionsInterventions that quantitatively evaluated dietary sodium intake for equal to or greater than four weeks duration were considered. Only studies that included two study arms comprising different levels of sodium intake were included. Types of outcomesStudies that reported SBP, diastolic blood pressure (DBP), pulse wave velocity (PWV), pulse wave analysis or flow mediated dilatation were considered. Types of studiesExperimental study designs including randomized controlled trials and non-randomized controlled trials were considered. Search strategyAn initial search strategy was conducted on databases MEDLINE and CINAHL before an extensive search of all relevant published and gray literature databases, and clinical trial registries were searched. Methodological qualityPotential papers were assessed for methodological validity using the standardized critical appraisal instrument from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI). Data extractionQuantitative data were extracted from papers using the standardized data extraction tool from JBI-MAStARI. Data synthesisQuantitative data were pooled in statistical meta-analysis. Effect sizes were expressed as weighted mean differences and 95% confidence intervals. Meta-analysis was conducted using a random-effect model, and heterogeneity assessed statistically using the standard Chi-square test and the I2 index. A priori sub-group analysis was undertaken on studies achieving ≥40 mmol versus <40 mmol in urinary sodium excretion and post hoc on studies with a mean body mass index (BMI) ≥ 30 versus less than 30. ResultsFive trials were included with a total of 1214 participants. The overall reduction in SBP was −0.71 mmHg (95% CI: −2.62, 1.20, P = 0.47) and DBP −0.57 mmHg (95% CI: −1.26, 0.12, P = 0.10). There was no significant change in PWV following reduction of dietary sodium over a four to six-week period. Sub-group analysis did not find a significant effect of urinary sodium excretion or BMI on outcomes; however, a trend toward a greater reduction in BP was observed in those with a higher BMI (MD −2.41, 95% CI −5.72, +0.91, P = 0.16). ConclusionBlood pressure in normotensive participants was not significantly affected by sodium modification and was controlled to within 1% of baseline values. Reducing dietary sodium in normotensive participants may still be of importance for cardiovascular risk management; however, good quality interventional research is limited.