Post-diuretic spot urine sodium assessment in acute heart failure: a retrospective analysis

AIMS

To provide real-world data on post-diuretic spot urine sodium concentration (UNa) assessment in acute heart failure (AHF) and its implications for treatment.

METHODS AND RESULTS

Automated query of the electronic medical record identified patients admitted to the cardiac intensive care unit of a single tertiary care hospital between November 2018 and December 2021, who received intravenous loop diuretics. Detailed manual chart review confirmed the AHF diagnosis. Stratification was performed based on whether post-diuretic UNa was assessed within 24 h of admission. AHF was confirmed in 340/380 identified patients. Post-diuretic UNa was assessed in 117 (34%), more frequently when ejection fraction was reduced and heart failure more advanced. Patients with versus without post-diuretic UNa assessment received higher doses of intravenous loop diuretics and more frequently acetazolamide and thiazide-like diuretics (p < 0.001 for all), resulting in similar urine output despite more advanced heart failure [2,488 mL (1,740-4,033 mL) vs. 2,400 mL (1,553-3,250 mL), respectively; p = 0.170]. Diuretic therapy remained more intense at discharge in the post-diuretic UNa group, with also a higher prescription rate of angiotensin-neprilysin inhibitors (p = 0.021). Serum creatinine increases/decreases were similarly frequent irrespectively from UNa assessment, with more dynamic changes observed in patients with UNa ≤ 80 mmol/L versus ≥ 81 mmol/L. After adjustments for baseline characteristics, the risk for death or heart failure readmission was similar in patients with versus without UNa assessment [HR (95%CI) = 1.43 (0.88-2.32); p = 0.150].

CONCLUSION

Post-diuretic UNa assessment in AHF was associated with more intense diuretic regimens, preserving urine output despite its use in a sicker population.

Implementation of a multi-modal intervention adopting new technologies, clinical services, and feedback improves catheter-associated urinary tract infections

OBJECTIVES

Catheter-associated urinary tract infections (CAUTI) are a significant cause of morbidity and financial burden to healthcare systems. The aim of this study was to develop and implement a program designed to reduce Foley catheter use days and associated CAUTI rates.

METHODS

A retrospective evaluation of a multi-modal program aimed toward reducing Foley catheter use days and associated CAUTI rates across the Indiana University Health (IUH) system was conducted. IUH is comprised of 16 hospitals and 2,703 available beds. The program included the adoption of new technologies with evidence-based clinical training materials based on change management and feedback from clinicians. National Healthcare Safety Network Standardized Infection Ratio (SIR), Standardized Utilization Ratio (SUR), and Incidence Density Ratio (IDR) rates were assessed.

RESULTS

Implementation of the multi-modal program resulted in a significant reduction in SIR, SUR, and IDR in the post-implementation compared to the baseline periods.

CONCLUSIONS

Through CAUTI bundle workflow assessments, education, and interventions designed to standardize practice variation, the program was successfully implemented and resulted in a significant decrease in Foley Catheter use days, and associated CAUTI rates.

A Urine-based DNA Methylation Marker Test to Detect Upper Tract Urothelial Carcinoma: A Prospective Cohort Study

PURPOSE

We explored the accuracy of a urine-based epigenetic test for detecting upper tract urothelial carcinoma.

MATERIALS AND METHODS

Under an Institutional Review Board-approved protocol, urine samples were prospectively collected from primary upper tract urothelial carcinoma patients before radical nephroureterectomy, ureterectomy, or ureteroscopy between December 2019 and March 2022. Samples were analyzed with Bladder CARE, a urine-based test that measures the methylation levels of 3 cancer biomarkers (TRNA-Cys, SIM2, and NKX1-1) and 2 internal control loci using methylation-sensitive restriction enzymes coupled with quantitative polymerase chain reaction. Results were reported as the Bladder CARE Index score and quantitatively categorized as positive (>5), high risk (2.5-5), or negative (<2.5). The findings were compared with those of 1:1 sex/age-matched cancer-free healthy individuals.

RESULTS

Fifty patients (40 radical nephroureterectomy, 7 ureterectomy, and 3 ureteroscopy) with a median (IQR) age of 72 (64-79) years were included. Bladder CARE Index results were positive in 47, high risk in 1, and negative in 2 patients. A significant correlation was found between Bladder CARE Index values and tumor size. Urine cytology was available for 35 patients, of whom 22 (63%) results were false-negative. Upper tract urothelial carcinoma patients had significantly higher Bladder CARE Index values compared to the controls (mean 189.3 vs 1.6, P < .001). The sensitivity, specificity, positive predictive value, and negative predictive value of the Bladder CARE test for detecting upper tract urothelial carcinoma were 96%, 88%, 89%, and 96%, respectively.Conclusions:Bladder CARE is an accurate urine-based epigenetic test for the diagnosis of upper tract urothelial carcinoma, with much higher sensitivity than standard urine cytology.

Best methods for urine sample collection for diagnostic accuracy in women with urinary tract infection symptoms: a systematic review

BACKGROUND

Most guidelines recommend a midstream urine (MSU) or a midstream clean-catch (MSCC) sample for urinalysis. However, whether this sample is better than others is still controversial.

OBJECTIVES

To assess the most adequate non-invasive method to collect a urine specimen for diagnosing urinary tract infections (UTI) in symptomatic non-pregnant women.

METHODS

This review was conducted according to the Systematic Reviews of Diagnostic Test Accuracy guidelines (PROSPERO CRD42021241758). PubMed was searched paired sample studies and controlled trials. Studies comparing MSCC, MSU without cleaning, first-void urine, and random voiding samples were considered. Studies evaluating invasive methods were excluded. The main outcome was diagnostic accuracy of urine cultures. Contamination rates were evaluated. The risk of bias tool for systematic reviews on diagnostic accuracy (QUADAS-2) was assessed.

RESULTS

Six studies including 1,010 patients were evaluated. Only two studies used paired samples. No study was considered as having low risk of bias. There was no difference in contamination for MSU specimens collected with or without cleansing and between random void urine collection and MSCC. In one study comparing first-void urine with MSU samples, the contamination rate was lower in the latter, but the gold standard of urine culture was only used for one sampling collection.

CONCLUSIONS

To the best of our knowledge, this systematic review is the first to assess the evidence available from different exclusively non-invasive urine sampling. Despite being widely recommended, our review did not find consistent evidence that asking women to provide midstream samples with or without cleansing is better.

Specialist Care, Metabolic Testing, and Testing Completeness Among U.S. Veterans with Urinary Stone Disease

Purpose

Recent observational studies reporting a lack of benefit from 24-hour urine testing for urinary stone disease (USD) prevention assumed testing included all components recommended from clinical guidelines. We sought to assess the completeness of 24-hour urine testing in the VA population.

Materials and methods

From the VHA Corporate Data Warehouse (2012-2019), we identified patients with USD (n=198,621) and determined those who saw a urologist and/or nephrologist, and received 24-hour urine testing within 12 months of their index USD encounter. Through Logical Observation Identifiers Names and Codes, we evaluated each collection's completeness, defined as including all of urine volume, calcium, oxalate, citrate, uric acid, and creatinine. We then fit a multilevel logistic regression model with random effects for VHA facility to evaluate factors associated with specialist follow-up, testing, and testing completeness.

Results

Specialist follow-up occurred in 54.3% and was stable over time. Testing occurred in 8.4%, declining from 9.3% in 2012 to 7.2% in 2019. Of tests performed, 54.6% were complete (43.7% increasing to 62.7% from 2012-2019). In adjusted analysis, there was high between-facility variation in specialist follow-up (median OR 2.0; 95% CI 1.7-2.0), testing (median OR 2.2, 95% CI 1.9-2.4), and testing completeness (median OR, 6.0, 95% CI 4.5-7.3). Individual facilities contributed 52% (intraclass correlation coefficient, 0.52; 95% CI, 0.44-0.57) towards the observed variation in testing completeness.

Conclusions

Approximately 1 in 12 U.S. Veterans with USD receive metabolic testing and half of these tests are complete. Addressing facility level variation in testing completeness may improve USD care.

GPs' perspectives on diagnosing childhood urinary tract infections: a qualitative study

BACKGROUND

Diagnosis and management of childhood urinary tract infection (UTI) is challenging in general practice because of a range of factors.

AIM

To explore GPs' perspectives concerning the barriers to and facilitators for diagnosis and management of childhood UTI.

DESIGN AND SETTING

Qualitative study in general practice in Belgium.

METHOD

Semi-structured interviews with 23 GPs from January 2021 to June 2021 were carried out. Interviews were video-recorded and audio-recorded, transcribed verbatim, and analysed using a thematic approach.

RESULTS

The barriers to early diagnosis of UTI were the assumption of low UTI prevalence and aspecific presentation of UTI in children, difficulties in urine collection, and diagnostic uncertainty. All GPs indicated that they sampled urine in either children with specific UTI features (for example, dysuria, abdominal pain) or unexplained fever. Facilitators for UTI screening were instructional material for parents, skill training for GPs, additional nursing staff, novel non-invasive convenient collection methods, online decision support informing parents when to bring a urine sample to the consultation, and an accurate, easy-to-use point-of-care test for UTI. Empirical antibiotic treatment was initiated based on dipstick test results, clinical features suggestive of UTI, severity of illness, gut feeling, long duration of fever, time of the day, and parents' ability to judge disease severity.

CONCLUSION

The assumption of a low UTI prevalence, absence of obvious UTI features, and difficult urine sampling might cause childhood UTIs to go undetected in general practice. Diagnostic uncertainty makes appropriate treatment challenging.

Comparison of Selective Versus Empiric Pharmacologic Preventive Therapy of Kidney Stone Recurrence with High-Risk Features

OBJECTIVE

To compare the frequency of stone-related events among subgroups of high-risk patients with and without 24-hour urine testing before PPT prescription. While recent studies show, on average, no benefit to a selective approach to preventive pharmacological therapy (PPT) for urinary stone disease (USD), there could be heterogeneity in treatment effect across patient subgroups.

MATERIALS AND METHODS

Using medical claims data from working-age adults and their dependents with USD (2008-2019), we identified those with a prescription fill for a PPT agent (thiazide diuretic, alkali therapy, or allopurinol). We then stratified patients into subgroups based on the presence of a concomitant condition or other factors that raised their stone recurrence risk. Finally, we fit multivariable regression models to measure the association between stone-related events (emergency department visit, hospitalization, and surgery) and 24-hour urine testing before PPT prescription by high-risk subgroup.

RESULTS

Overall, 8,369 adults with USD had a concomitant condition that raised their recurrence risk. Thirty-three percent (n=2,722) of these patients were prescribed PPT after 24-hour urine testing (median follow-up, 590 days), and 67% (n=5,647) received PPT empirically (median follow-up, 533 days). Compared to patients treated empirically, those with a history of recurrent USD had a significantly lower hazard of a subsequent stone-related event if they received selective PPT (hazard ratio, 0.83; 95% CI, 0.71-0.96). No significant associations were noted for selective PPT in the other high-risk subgroups.

CONCLUSIONS

Patients with a history of recurrent USD benefit from PPT when guided by findings from 24-hour urine testing.

β-Defensin 2, an Antimicrobial Peptide, as a Novel Biomarker for Ulcerative Interstitial Cystitis; Can β-Defensin 2 Suspect the Dysbiosis of Urine Microbiota?

As urine is not sterile, inflammatory reactions caused by dysbiosis of the urinary microbiota may induce interstitial cystitis. A study was conducted to determine whether β-defensin 2 (BD-2), a specific antimicrobial peptide in the bladder, could be used as a novel diagnostic marker for ulcerative interstitial cystitis (IC). Urine samples from three female groups were examined: healthy controls (n = 34, Control group), non-Hunner type IC (n = 40, NHIC group), and Hunner type IC (n = 68, HIC group). Urine samples were collected via a transurethral catheter and assayed for BD-2 levels using enzyme linked immunosorbent assay. Under general or regional anesthesia, cystoscopy with diagnostic and therapeutic hydrodistension was performed in NHIC and HIC groups patients. These patients underwent a biopsy of the bladders. Based on the urinary specimens from 142 patients, BD-2 expression was found to be 18-fold higher in patients with Hunner type IC than in patients with non-Hunner type IC. The enhanced secretion of BD-2 exhibited a strong correlation with increased mast cell counts associated with bladder IC pathology. Enhanced urinary secretion of the antimicrobial peptide BD-2 from Hunner type IC patients associated with clinical phenotypes and demonstrated relatively robust levels to be used as a potential biomarker. Moreover, the increased urinary level of BD-2 may suggest a new possibility of biomarkers caused by dysbiosis of the urinary microbiota in ulcerative IC.

Urine collection devices to reduce contamination in urine samples for diagnosis of uncomplicated UTI: a single-blind randomised controlled trial in primary care

BACKGROUND

Urine collection devices (UCDs) are being marketed and used in clinical settings to reduce urine sample contamination, despite inadequate supporting evidence.

AIM

To determine whether UCDs, compared with standardised instructions for urine sample collection, reduce the proportion of contaminated samples.

DESIGN AND SETTING

Single-blind randomised controlled trial in general practices in England and Wales.

METHOD

Women aged ≥18 years presenting with symptoms attributable to urinary tract infection (UTI) were randomised (1:1:1) to use either a Peezy UCD or a Whiz Midstream UCD, or were given standardised verbal instructions (SVI) for midstream sample collection. The primary outcome was the proportion of urine samples reported as contaminated by microbiology laboratory analysis.

RESULTS

A total of 1264 women (Peezy UCD: n = 424; Whiz Midstream UCD: n = 421; SVI: n = 419) were randomised between October 2016 and August 2018. Ninety women were excluded from the primary analysis as a result of ineligibility or lack of primary outcome data, leaving 1174 (Peezy UCD: n = 381; Whiz Midstream UCD: n = 390; SVI: n = 403) for intention-to-treat analysis. The proportion of contaminated samples was 26.5% with the Peezy UCD, 28.2% with the Whiz Midstream UCD, and 29.0% with SVI (relative risk: Peezy UCD versus SVI = 0.91, 95% CI = 0.76 to 1.09, P = 0.32; Whiz Midstream UCD versus SVI = 0.98, 95% CI = 0.97 to 1.20, P = 0.82). There were 100 (25.3%) device failures with the Peezy UCD and 35 (8.8%) with the Whiz Midstream UCD; the proportion of contaminated samples was similar after device failure samples were excluded.

CONCLUSION

Neither the Peezy UCD nor the Whiz Midstream UCD reduced urine sample contamination when used by women presenting to primary care with suspected UTI. Their use cannot be recommended for this purpose in this setting.

Urinary Alpha1-Microglobulin: A New Predictor for In-Hospital Mortality in Patients with ST-Segment Elevation Myocardial Infarction

BACKGROUND Alpha1-microglobulin (A1MG) is a small molecular protein related to oxidation and inflammation. It exists in diverse body fluids, including urine. Results from urine tests are sometimes neglected when predicting in-hospital prognosis. It remains unclear whether urinary A1MG (UA1MG) can predict short-term prognosis of ST-elevated myocardial infarction (STEMI). MATERIAL AND METHODS A total of 1854 hospitalized patients with acute STEMI were retrospectively enrolled in our study. Medical records were used to obtain patient demographic and clinical information, UA1MG values (which were used to divide patients into groups of low, medium, or high), and other laboratory parameters. Principal clinical outcomes of interest were all-cause in-hospital deaths, cardiac deaths, and major adverse cardiac events (MACEs). RESULTS Among the 1854 enrolled patients, 43 (2.3%) died in the hospital, of which 33 (1.8%) were cardiac deaths. MACEs were noted in 113 patients (6.1%) during hospitalization. The group with the highest UA1MG value showed a significantly higher frequency of in-hospital deaths, cardiac deaths, and MACEs, compared to those of the lowest UA1MG value group (4.4% vs. 1.0%, P<0.001; 3.1% vs. 0.6%, P<0.005; and 8.6% vs. 4.7%, P=0.007, respectively). Multivariate regression analysis revealed that UA1MG levels (odds ratio 1.109, 95% confidence interval (CI) 1.027-1.197, P=0.008) independently predicted all-cause in-hospital mortality. A UA1MG value of 3.23 mg/dL was considered as an optimal cutoff point in STEMI to predict all-cause mortality after receiver operating characteristic curve analysis (area under the curve 0.73, 95% CI 0.65-0.80, P<0.001). CONCLUSIONS The UA1MG value at hospital admission could be an independent prognostic factor of all-cause in-hospital mortality in patients with STEMI.

Detection and correction of incomplete duplicate 24-hour urine collections - theory and practical evidence

Introduction

The intraindividual variability in urinary creatinine excretion is notoriously large. The aims of this study were to investigate the variability of duplicate consecutive 24-hour urinary creatinine excretions in patients and to develop a model for the detection and correction of discrepant creatinine excretions.

Materials and methods

A group of 270 patients (82 men and 188 women) were included in the study. We collected the following data: urinary 24-hour volumes (volumetric/gravimetric) and urinary creatinine concentrations (Jaffé/enzymatic) on both collection days. We performed specific calculations to detect discrepant creatinine excretions.

Results

In 60 patients (22%) discrepant collections were found. Among the remaining 78%, 22% of the patients collected very accurately (almost identical urinary creatinine excretions). In this subgroup the volume ratios and the creatinine concentration ratios behave inversely as in a dilution curve. A theoretical model and six collection scenarios were developed to detect, interpret and correct discrepant collections. Practical examples are given to illustrate the use of the model in successful correction of creatinine and other analytes for under- or overcollection.

Conclusions

We conclude that missed or overcollected urine volumes are the largest source of variation in creatinine excretion. Discrepancies in consecutive duplicate 24-hour creatinine excretions can be detected and corrected with specific calculations by means of the presented model. The effectiveness of these corrections is demonstrated with examples from daily practice. These calculations can be easily automated.

Diagnosis, prevention and control of urinary tract infections: a survey of routine practices in Belgian nursing homes

Background

Urinary tract infections (UTIs) are one of the most frequently reported infections in older adults and the most common reason for antimicrobial prescribing in nursing homes (NHs). In this vulnerable population, both a good diagnosis and prevention of these infections are crucial as overuse of antibiotics can lead to a variety of negative consequences including the development of multidrug-resistant organisms.

Objective

To determine infection prevention and control (IPC) and diagnostic practices for UTIs in Belgian NHs.

Methods

Local staff members had to complete an institution-level questionnaire exploring the availability of IPC practices and resources and procedures for UTI surveillance, diagnosis, and urinary catheter and incontinence care.

Results

UTIs were the second most common infections in the 87 participating NHs (prevalence: 1.0%). Dipstick tests and urine cultures were routinely performed in 30.2% and 44.6% of the facilities, respectively. In non-catheterised residents, voided or midstream urine sampling was most frequently applied. Protocols/guidelines for urine sampling, urinary catheter care and incontinence care were available in 43.7%, 45.9% and 31.0% of the NHs, respectively. Indwelling catheters were uncommon (2.3% of the residents) and urinary retention (84.9%) and wound management (48.8%) were the most commonly reported indications. Only surveillance was found to significantly impact the UTI prevalence: 2.2% versus 0.8% in NHs with or without surveillance, respectively (P < 0.001).

Discussion

This survey identified key areas for improving the diagnosis and prevention of UTIs, such as education and training regarding the basics of urine collection and catheter care.

What's the catch? Urine sample collection from young pre-continent children: a qualitative study in primary care

Background

Urinary tract infections (UTIs) are common in young pre-continent children, but collecting urine samples is challenging. Collection methods all have limitations and international guidelines have conflicting recommendations. Choice of method must balance time, resources, invasiveness, reliability, and contamination. Evidence from primary care clinicians is limited regarding barriers and enablers to sample collection, and what factors inform the choice and use of different sample collection methods.

Aim

To understand the barriers and enablers to collecting urine samples from young pre-continent children in primary care.

Design & setting

An exploratory qualitative study performed in primary care in Australia.

Method

Semi-structured interviews explored the topic of collecting a urine sample from a child aged 6 months who presented with a fever. The interviews were undertaken with 21 GPs and four practice nurses (PNs) until data saturation was reached. Interviews were audiorecorded, transcribed verbatim, coded, and underwent content and thematic analysis.

Results

Five main themes emerged including: the clinician’s knowledge and expertise; patient characteristics; parent or carer’s understanding and motivation; the collection process itself; and likely outcome of the chosen method. Non-invasive methods were strongly favoured; although, clean catch was considered time-consuming and urine bags were known to be often contaminated. Invasive methods (for example, catheterisation or suprapubic aspiration [SPA]) were rarely performed outside of remote settings. Key barriers included time and space constraints in clinics, and key enablers included parental motivation, education handouts, and voiding stimulation methods.

Conclusion

This study has identified key barriers and enablers to inform education, policy, and future research for urine sample collection from pre-continent children in primary care. Guideline recommendations must consider the primary care context to ensure they are relevant and suited to real-world practice.

Association of Chronic Kidney Disease Stage with 24-Hour Urine Values Among Patients with Nephrolithiasis

Introduction: Nephrolithiasis is a known risk factor for chronic kidney disease (CKD); however, it is unknown how CKD affects urinary parameters related to stone risk. The purpose of this study was to assess the relationship of diminishing glomerular filtration rate (GFR) and kidney stone-related 24-hour urine (24H urine) composition. Materials and Methods: A single-institution retrospective review of patients (n = 2057) who underwent 24H urine analysis was performed. The serum creatinine within 1 year of the first 24H urine was used to determine estimated GFR and stratify patients by CKD stage. We performed analysis of variance and multivariable linear regression to assess the relationship of GFR and urinary analytes. Results: Among all patients, there were 184 (8.9%), 1537 (74.7%), 245 (11.9%), 70 (3.4%), 17 (0.8%), and 4 (0.2%) in CKD stage I, II, IIIa, IIIb, IV, and V groups, respectively. On analysis of 24H urine composition, as CKD increased, changes in urinary parameters protective against crystallization included decreased calcium and uric acid (UA) (P < 0.001). In addition, parameters favoring crystallization included decreased citrate and magnesium (P = 0.002 and P < 0.001, respectively). The net effect with increasing GFR was decreasing supersaturation of calcium oxalate and phosphate. On linear regression, urinary excretion of calcium, oxalate, citrate, UA, phosphate, and ammonia all decreased with decreasing GFR (all P < 0.05). Conclusions: Higher CKD stage was associated with changes in urinary analytes that both promoted and inhibited stone formation, with the net effect of decreasing calcium oxalate and phosphate supersaturation. These patients may benefit from medical therapy that targets improving urinary citrate instead of lowering calcium or UA.

Liquid gold: the cost-effectiveness of urine sample collection methods for young precontinent children

BACKGROUND

Urinary tract infection (UTI) is a common childhood infection. Many febrile children require a urine sample to diagnose or exclude UTI. Collecting urine from young children can be time-consuming, unsuccessful or contaminated. Cost-effectiveness of each collection method in the emergency department is unknown.

OBJECTIVE

To determine the cost-effectiveness of urine collection methods for precontinent children.

METHODS

A cost-effectiveness analysis was conducted comparing non-invasive (urine bag, clean catch and 5 min voiding stimulation for clean catch) and invasive (catheterisation and suprapubic aspirate (SPA)) collection methods, for children aged 0-24 months in the emergency department. Costs included equipment, staff time and hospital bed occupancy. If initial collection attempts were unsuccessful subsequent collection using catheterisation was assumed. The final outcome was a definitive sample incorporating progressive dipstick, culture and contamination results. Average costs and outcomes were calculated for initial collection attempts and obtaining a definitive sample. One-way and probabilistic sensitivity analyses were performed.

RESULTS

For initial collection attempts, catheterisation had the lowest cost per successful collection (GBP£25.98) compared with SPA (£37.80), voiding stimulation (£41.32), clean catch (£52.84) and urine bag (£92.60). For definitive collection, catheterisation had the lowest cost per definitive sample (£49.39) compared with SPA (£51.84), voiding stimulation (£52.25), clean catch (£64.82) and urine bag (£112.28). Time occupying a hospital bed was the most significant determinant of cost.

CONCLUSION

Catheterisation is the most cost-effective urine collection method, and voiding stimulation is the most cost-effective non-invasive method. Urine bags are the most expensive method. Although clinical factors influence choice of method, considering cost-effectiveness for this common procedure has potential for significant aggregate savings.

Comparison of 24-hour urine and 24-hour diet recall for estimating dietary sodium intake in populations: A systematic review and meta-analysis

This systematic literature review and meta-analysis examined whether 24-hour diet recall is a valid way to measure mean population sodium intake compared with the gold standard 24-hour urinary assessment. The authors searched electronic databases MEDLINE, Embase, and Scopus using pre-defined terms. Studies were eligible for inclusion if they assessed adult humans in free-living settings, and if they included group means for 24-hour diet recall and 24-hour urinary collection of sodium intake in the same participants. Studies that included populations with an active disease state that might interfere with normal sodium metabolism were excluded. Results of 28 studies are included in the meta-analysis. Overall, 24-hour diet recall underestimated population mean sodium intake by an average of 607 mg per day compared to the 24-hour urine collection. The difference between measures from 24-hour urine and 24-hour diet recall was smaller in studies conducted in high-income countries, in studies where multiple-pass methods of 24-hour diet recall were reported and where urine was validated for completeness. Higher quality studies also reported smaller differences between measures than lower quality studies. Monitoring of population sodium intake with 24-hour urinary excretion remains the most accurate method of assessment. Twenty-four-hour diet recall tends to underestimate intake, although high-quality 24-hour diet recall improves accuracy, and may be used if 24-hour urine is not feasible.

Nutritional Assessment of Childhood Cancer Survivors (the Swiss Childhood Cancer Survivor Study-Nutrition): Protocol for a Multicenter Observational Study

Background

Childhood cancer survivors are at high risk of developing adverse late health effects. Poor nutritional intake may contribute to this risk, but information about dietary intake is limited.

Objective

This study will assess childhood cancer survivors’ dietary intake and compare two dietary assessment tools: a self-reported food frequency questionnaire, and dietary measurements from urine spot samples.

Methods

In a substudy of the Swiss Childhood Cancer Survivor Study (SCCSS), SCCSS-Nutrition, we assessed childhood cancer survivors’ dietary intake via a validated food frequency questionnaire. We sent a urine spot collection kit to a subset of 212 childhood cancer survivors from the French-speaking region of Switzerland to analyze urinary sodium, potassium, urea, urate, creatinine, and phosphate content. We will compare the food frequency questionnaire results with the urine spot analyses to quantify childhood cancer survivors’ intake of various nutrients. We collected data between March 2016 and March 2018.

Results

We contacted 1599 childhood cancer survivors, of whom 919 (57.47%) returned a food frequency questionnaire. We excluded 11 childhood cancer survivors who were pregnant or were breastfeeding, 35 with missing dietary data, and 71 who had unreliable food frequency questionnaire data, resulting in 802 childhood cancer survivors available for food frequency questionnaire analyses. To a subset of 212 childhood cancer survivors in French-speaking Switzerland we sent a urine spot collection kit, and 111 (52.4%) returned a urine sample. We expect to have the results from analyses of these samples in mid-2019.

Conclusions

The SCCSS-Nutrition study has collected in-depth dietary data that will allow us to assess dietary intake and quality and compare two dietary assessment tools. This study will contribute to the knowledge of nutrition among childhood cancer survivors and is a step toward surveillance guidelines and targeted nutritional recommendations for childhood cancer survivors in Switzerland.

Trial Registration

ClinicalTrials.gov NCT03297034; https://clinicaltrials.gov/ct2/show/NCT03297034

International Registered Report Identifier (IRRID)

DERR1-10.2196/14427

Twenty-Four-Hour Diet recall and Diet records compared with 24-hour urinary excretion to predict an individual's sodium consumption: A Systematic Review

This systematic literature review aimed to investigate whether 24 hour diet recall and diet records are reliable and valid ways to measure usual dietary sodium intake compared with 24 hour urinary assessment. We searched electronic databases Medline, Embase, Cinahl, Lilacs, Google Scholar and the Cochrane Library using pre-defined terms Studies were eligible for inclusion if they assessed adult humans in free-living settings, and if they included dietary assessment and 24 hours urinary collection for assessment of sodium intake in the same participants. Studies that included populations with an active disease state that might interfere with normal sodium metabolism were excluded. Results of 20 studies using 24 hour diet recall recall (including 14 validation studies) and 10 studies using food records (including six validation studies) are included in this review. Correlations between estimates from dietary assessment and urinary excretion ranged from 0.16 to 0.72 for 24 hour diet recall, and 0.11 to 0.49 for food diaries. Bland-Altman analysis in two studies of 24 hour diet recall showed poor agreement with 24 hours urinary sodium excretion. These results show that 24 hour diet recall and diet records inaccurately measure dietary sodium intake in individuals compared with the gold standard 24 hours urinary excretion. Validation studies of dietary assessment methods should include multiple days of assessment and 24 hours urine collection, use relevant food composition databases and Bland-Altman methods of analysis.

Validation of single measurement of 12-hour urine excretion for estimation of sodium and potassium intake. A longitudinal study

BACKGROUND

Evaluation of sodium and potassium intake can be carried out using different methods. Biological markers are able to capture intra and inter-individual variability and are used as separate measurements of consumption. The aim of this study was to test the validity of a single measurement of urinary sodium and potassium excretion as representative of habitual intake.

DESIGN AND SETTING

Longitudinal study, federal university.

METHODS

Food consumption data from a sample of adult university students and public servants (25 to 74 years old) were collected through 24-hour records and 12-hour urinary sodium and potassium excretion at five different times over a one-year period. The dietary data were entered into a nutritional research data software system and the sodium and potassium intakes were estimated. The variables were tested for normal distribution using the Kolmogorov-Smirnov test. One-way analysis of variance or the Kruskal-Wallis test was used to evaluate means. Correlations between measurements using Pearson or Spearman coefficients were calculated. The degree of agreement between the five measurements was given by the intraclass correlation coefficient.

RESULTS

Satisfactory agreement was found between the five measurements of urinary sodium and potassium excretion over a year, with little variability in consumption.

CONCLUSION

A single measurement of urinary sodium and potassium accurately estimated the usual average consumption of these electrolytes. This can be used in population-based studies.

Agreement between 24-hour salt ingestion and sodium excretion in a controlled environment

Accurately collected 24-hour urine collections are presumed to be valid for estimating salt intake in individuals. We performed 2 independent ultralong-term salt balance studies lasting 105 (4 men) and 205 (6 men) days in 10 men simulating a flight to Mars. We controlled dietary intake of all constituents for months at salt intakes of 12, 9, and 6 g/d and collected all urine. The subjects' daily menus consisted of 27 279 individual servings, of which 83.0% were completely consumed, 16.5% completely rejected, and 0.5% incompletely consumed. Urinary recovery of dietary salt was 92% of recorded intake, indicating long-term steady-state sodium balance in both studies. Even at fixed salt intake, 24-hour urine collection for sodium excretion (UNaV) showed infradian rhythmicity. We defined a ±25 mmol deviation from the average difference between recorded sodium intake and UNaV as the prediction interval to accurately classify a 3-g difference in salt intake. Because of the biological variability in UNaV, only every other daily urine sample correctly classified a 3-g difference in salt intake (49%). By increasing the observations to 3 consecutive 24-hour collections and sodium intakes, classification accuracy improved to 75%. Collecting seven 24-hour urines and sodium intake samples improved classification accuracy to 92%. We conclude that single 24-hour urine collections at intakes ranging from 6 to 12 g salt per day were not suitable to detect a 3-g difference in individual salt intake. Repeated measurements of 24-hour UNaV improve precision. This knowledge could be relevant to patient care and the conduct of intervention trials.

Cross-Sectional Study of 24-Hour Urinary Electrolyte Excretion and Associated Health Outcomes in a Convenience Sample of Australian Primary Schoolchildren: The Salt and Other Nutrients in Children (SONIC) Study Protocol

BACKGROUND

Dietary sodium and potassium are involved in the pathogenesis of cardiovascular disease. Data exploring the cardiovascular outcomes associated with these electrolytes within Australian children is sparse. Furthermore, an objective measure of sodium and potassium intake within this group is lacking.

OBJECTIVE

The primary aim of the Salt and Other Nutrient Intakes in Children ("SONIC") study was to measure sodium and potassium intakes in a sample of primary schoolchildren located in Victoria, Australia, using 24-hour urine collections. Secondary aims were to identify the dietary sources of sodium and potassium, examine the association between these electrolytes and cardiovascular risk factors, and assess children's taste preferences and saltiness perception of manufactured foods.

METHODS

A cross-sectional study was conducted in a convenience sample of schoolchildren attending primary schools in Victoria, Australia. Participants completed one 24-hour urine collection, which was analyzed for sodium, potassium, and creatinine. Completeness of collections was assessed using collection time, total volume, and urinary creatinine. One 24-hour dietary recall was completed to assess dietary intake. Other data collected included blood pressure, body weight, height, waist and hip circumference. Children were also presented with high and low sodium variants of food products and asked to discriminate salt level and choose their preferred variant. Parents provided demographic information and information on use of discretionary salt. Descriptive statistics will be used to describe sodium and potassium intakes. Linear and logistic regression models with clustered robust standard errors will be used to assess the association between electrolyte intake and health outcomes (blood pressure and body mass index/BMI z-score and waist circumference) and to assess differences in taste preference and discrimination between high and low sodium foods, and correlations between preference, sodium intake, and covariates.

RESULTS

A total of 780 children across 43 schools participated. The results from this study are expected at the end of 2015.

CONCLUSIONS

This study will provide the first objective measure of sodium and potassium intake in Australian schoolchildren and improve our understanding of the relationship of these electrolytes to cardiovascular risk factors. Furthermore, this study will provide insight into child taste preferences and explore related factors. Given the cardiovascular implications of consuming too much sodium and too little potassium, monitoring of these nutrients during childhood is an important public health initiative.

Low level of adherence to instructions for 24-hour urine collection among hospital outpatients

INTRODUCTION

We hypothesized that patients are poorly informed about proper procedure for 24-hour urine specimen collection and its relevance in determination of biochemical analytes, despite availability of leaflets and webpage with instruction for collection. The aim of this survey was to question outpatients how well are they informed about procedure of 24-hour urine specimen collection.

MATERIALS AND METHODS

The survey with 10 questions was done in outpatient laboratory of University Department of Chemistry, Medical School University Hospital Sestre Milosrdnice, Zagreb, Croatia. The study included 59 patients with collected 24-hour urine sample who have consented to participate in the survey.

RESULTS

Out of 59 participants, most of them (0.97) were older than 40 years. Internet was not recognized as a source of information (1/59). Almost one third of the patients have changed their drinking habits to collect more urine volume. Although most of the patients (0.60) were aware that the bottle of water is the best choice for the container, almost half of them were collected urine samples in the plastic soft drink bottle. Laboratory staff and physicians often have given information about proper collection procedure, but that information was insufficient.

CONCLUSIONS

Patients are usually not aware of importance of proper preanalytical procedure for collecting urine specimen and how improper collection could affect results of requested tests. Education of outpatients, general practitioners and laboratory staff is needed in order to improve sample quality and trueness of results.