Development, validation and application of a machine learning model to estimate salt consumption in 54 countries

Global targets to reduce salt intake have been proposed but their monitoring is challenged by the lack of population-based data on salt consumption. We developed a machine learning (ML) model to predict salt consumption at the population level based on simple predictors and applied this model to national surveys in 54 countries. We used 21 surveys with spot urine samples for the ML model derivation and validation; we developed a supervised ML regression model based on: sex, age, weight, height, systolic and diastolic blood pressure. We applied the ML model to 54 new surveys to quantify the mean salt consumption in the population. The pooled dataset in which we developed the ML model included 49,776 people. Overall, there were no substantial differences between the observed and ML-predicted mean salt intake (p<0.001). The pooled dataset where we applied the ML model included 166,677 people; the predicted mean salt consumption ranged from 6.8 g/day (95% CI: 6.8-6.8 g/day) in Eritrea to 10.0 g/day (95% CI: 9.9-10.0 g/day) in American Samoa. The countries with the highest predicted mean salt intake were in Western Pacific. The lowest predicted intake was found in Africa. The country-specific predicted mean salt intake was within reasonable difference from the best available evidence. A ML model based on readily available predictors estimated daily salt consumption with good accuracy. This model could be used to predict mean salt consumption in the general population where urine samples are not available.

Spot Urine Uric Acid to Creatinine Ratio used in the Estimation of Hyperuricosuria in the Young Korean Population

Background: Uric acid levels in urine are measured using urine specimens 24 hours or by uric acid glomerular filtration rate (UAGFR) with spot urine, which additionally requires a blood sample. This study aimed to investigate whether urinary uric acid creatinine ratio (UUACr) obtained by spot urine alone could be recognized as a substitute for UAGFR value, and hyperuricosuria can be screened by UUACr. UUACr is known to vary with age and regional differences. This study focused on the reference value of each value in Korean young populations.Method: We enrolled Korean subjects 1–20 years with normal kidney function, from a single hospital, classified into 5 age groups, 1–5 years, 6–8 years, 9–12 years, 13–15 years, and 16–20 years. We checked spot urine uric acid, creatinine and serum uric acid, creatinine levels on the same day from February 2014 to December 2018. We measured the average of UAGFR and UUACr in each groups. The UUACr cut-off value of the upper 2 standard deviation (SD) of UAGFR were taken.Results: The upper 2 SD of UUACr (mg/mg) and UAGFR (mg/dL) were determined in all age groups. UUACr decreased with grown up (P=0.000), but UAGFR were not statistically different among the groups. UUACr and UAGFR were not significantly different by gender. UUACr and UAGFR were positively correlated; UUACr cut-off value of upper 2 SD UAGFR (0.54 mg/dL) was 0.65 mg/mg in total age.Conclusions: UUACr could potentially be used to screen for hyperuricosuria.

STUDY OF MICROALBUMINURIA IN SEPSIS WITH REFERENCE TO APACHE II SCORE

Sepsis has very high morbidity and mortality, which leads to major healthcare burden in the world. Though there is far from advancement in the therapeutic options, the mortality rate remains high due to the delay in the diagnosis because of lack of availability of reliable diagnostic methods. In sepsis there is potent activation of inammatory cascade leads to endothelial dysfunction and increase in systemic capillary permeability. In kidney there is loss of barrier integrity and capillary leak in the glomerulus results in increased excretion of albumin in the urine. This study was done to evaluate the degree of microalbuminuria in sepsis in correlation with APACHE II score and to test whether the degree of microalbuminuria could predict the mortality in critically ill sepsis patients. Methodology: The present study was conducted on 50 patients admitted to medical emergency/ Medical ICU in Kamineni Institute of Medical Sciences Narketpally. Spot urine sample was collected within 6 hours and at 24 hours of admission to medical emergency/ICU /ward. Sample testedfor urine micro albumin by using immunoturbidometric method and for urine creatinine by Jaffee method. Urine albumin: creatinine ratio was calculated. (At 6 hours ACR-1 and at 24 hours ACR-2). APACHE II scoring was done at 24 hours of admission. Patients was followed up during hospital stay and the outcome of the patient (i.e., Death/Survival) is recorded. RESULTS: The present study included 50 patients, among which 31 were males and 19 were females. Mean age was 43.5 years. Mortality was 38%. Mortality was more among male patients than in female. APACHE II score ranges from 6 - 37, mean APACHE II among survivors were 16.35 with Standard Deviation of 6.78 and among non survivors were 25.47 with Standard Deviation of 6.93 with p value of <0.0001 for predicting mortality. Urine ACR 1 was 74.06±20.83 µgm/mg among survivors and 164.53±46.61 µgm /mg among non survivors and ACR 2 was 45.81±17.92µgm/mg among survivors and 157.84±36.96 µgm/mg among non survivors. Both were statistically signicant with p value of 0.0001 for predicting mortality. The degree of microalbuminuria correlates with disease severity. CONCLUSION: Signicant microalbuminuria is predictive of mortality which is equivalent to APACHE II score. Microalbuminuria is an inexpensive and rapid diagnostic tool. Serial measurements may help in the clinical assessment of critically ill patients at risk of worse prognosis, even in resource poor areas.

Diagnostic utility of protein excretion in 24-hour urine and the protein to creatinine ratio for adverse perinatal outcomes and time of delivery

Objective Our study aimed to evaluate the perinatal and neonatal outcomes of hypertensive pregnant women with or without proteinuria. We compared the predictivity of spot urinary protein to creatinine (P/C) ratio and 24-hour protein excretions on outcomes. Methods We retrospectively enrolled 230 pregnant women with a new diagnosis of hypertension between 20 and 37 weeks of gestation. We divided the patients into two groups according to the protein level determined by 24-hour urine collection and P/C ratio. The presence and level of proteinuria, its relationship with the P/C ratio, and the relationship between these findings and perinatal outcomes were evaluated. Results Gestational age at delivery weeks and latency period (duration between diagnosis of hypertension and delivery) were significantly earlier in pregnant women with ≥300 mg/24-h and P/C ratio ≥0.3. Adverse neonatal outcomes were significant in patients with proteinuria ≥300 mg/24-hour and P/C ratio ≥0.3. Urinary protein levels in 24-hour urine were significantly higher in pregnant women with P/C ratio ≥0.3 and a significantly positive correlation was found between 24-h proteinuria and P/C (r=0.382, p<0.001). Conclusion Our study demonstrated that a protein loss of ≥300 mg in 24-h and a P/C ratio in spot urine ≥0.3 in hypertensive pregnant women is associated with adverse perinatal outcomes. Furthermore, we have identified that proteinuria ≥300 mg/day and spot urine P/C ratio ≥0.3 in hypertensive pregnant women make them prone to early delivery risk.

Estimation of sodium consumption by novel formulas derived from random spot and 12-hour urine collection

The gold standard for estimating sodium intake is 24h urine sodium excretion. Several equations have been used to estimate 24h urine sodium excretion, however, a validated formula for calculating 24h urine sodium excretion from 12h urine collection has not yet been established. This study aims to develop novel equations for estimating 24h urine sodium excretion from 12h and random spot urine collection and also to validate existing spot urine equations in the Thai population. A cross-sectional survey was carried out among 209 adult hospital personnel. Participants were asked to perform a 12h daytime, 12h nighttime, and a random spot urine collection over a period of 24 hours. The mean 24h urine sodium excretion was 4,055±1,712 mg/day. Estimated urine sodium excretion from 3 different equations using random spot urine collection showed moderate correlation and agreement with actual 24h urine sodium excretion (r = 0.54, P<0.001, ICC = 0.53 for Kawasaki; r = 0.57, P<0.001, ICC = 0.44 for Tanaka; r = 0.60, P<0.001, ICC = 0.45 for INTERSALT). Novel equations for predicting 24h urine sodium excretion were then developed using variables derived from 12h daytime urine collection, 12h nighttime urine collection, random spot urine collection, 12h daytime with random spot urine collection, and 12h nighttime with random spot urine collection which showed strong correlation and agreement with actual measured values (r = 0.88, P<0.001, ICC = 0.87; r = 0.83, P<0.001, ICC = 0.81; r = 0.67, P<0.001, ICC = 0.62; r = 0.90, P<0.001, ICC = 0.90; and r = 0.83, p<0.001, ICC = 0.82 respectively). Bland-Altman plots indicated good agreement between predicted values and actual 24h urine sodium excretion using the new equations. Newly derived equations from 12h daytime and 12h nighttime urine collection with or without casual spot urine collection were able to accurately predict 24h urine sodium excretion.

Diabetic Foot Ulcer Risk with Diabetic Kidney Disease and Renal Failure among 10,680 Patients

Objectives: Patients with Diabetic Kidney Disease (DKD) and foot ulcer have poor prognosis. However, no study have found association of diabetic foot ulcer (DFU) with diabetic kidney dysfunction and their co-existing risk factors. Materials and Methods: This cross sectional study collected the data for 10,680 patients for 15 years. All variables were analyzed biochemically and statistically by standardized methodology. Results: Levels of HbA1c, creatinine, systolic and diastolic blood pressures, microalbuminuria, spot urine protein, and spot urine protein to creatinine ratio were higher among the groups with foot ulcers (p-value < 0.0001 for all). Average ABI was observed to be lower among the groups demonstrating nephropathy and DKD (p=0.025 and 0.022 respectively. DFU was significantly associated with HTN (odds ratio 2.2; 95% CI 1.66 to 2.9; p < 0.0001), nephropathy (odds ratio 4.77; 95% CI 3.53 to 6.5; p < 0.0001) and DKD (odds ratio 4.77 and 6.83; 95% CI 4.6 to 10.2; p < 0.0001). HbA1c of 7.8% was 60% sensitive and 52% specific for the development of DFU. Creatinine of 1.2 mg/dl was 75% sensitive and 48% specific for DFU. Spot urine protein excretion from nephrons of 35 mg/dl was 88% sensitive and 90% specific for the development of DFU. Conclusion: Nephropathy/DKD are risk factors for the development of DFU. With optimal diabetes control, regular and routine assessment of the feet and early screening of diabetic patients for neuropathy, nephropathy, hypertension, dyslipidaemia and other diabetic complications are essential. Doi: 10.28991/SciMedJ-2021-0304-6 Full Text: PDF

Urinary concentrations of neonicotinoid insecticides were related to renal tubular dysfunction and neuropsychological complaints in Dry-zone of Sri Lanka

Neonicotinoids are systemic insecticides used since the 1990’s , that possess renal tubular toxicity. We conducted a field-based descriptive study in the North Central Dry-zone of Sri Lanka, where chronic kidney disease (CKD) of unknown etiology has been increasing since the 1990’s. To elucidate the relationship between renal tubular dysfunctions and urinary neonicotinoids concentrations, we collected spot urine samples from15 CKD patients, 15 family members, and 62 neighbors in 2015, analyzed two renal tubular biomarkers, Cystatin-C and L-FABP, quantified seven neonicotinoids and a metabolite N-desmethyl-acetamiprid by LC–MS/MS; and we investigated their symptoms using a questionnaire. Cystatin-C and L-FABP had a positive correlation (p < 0.001). N-Desmethyl-acetamiprid was detected in 92.4% of the urine samples, followed by dinotefuran (17.4%), thiamethoxam (17.4%), clothianidin (9.8%), thiacloprid and imidacloprid. Dinotefuran and thiacloprid have never been registered in Sri Lanka. In High Cystatin-C group (> 70 μg/gCre, n = 7), higher urinary concentration of dinotefuran (p = 0.009), and in Zero Cystatin-C group (< LOQ, n = 7), higher N-desmethyl-acetamiprid (p = 0.013), dinotefuran (p = 0.049), and thiacloprid (p = 0.035), and more complaints of chest pains, stomachache, skin eruption and diarrhea (p < 0.05) were found than in Normal Cystatin-C group (n = 78). Urinary neonicotinoids may be one of the potential risk factors for renal tubular dysfunction in this area.

Validity of predictive equations for 24-h urinary sodium excretion at the population and individual levels among Chinese adults aged 18–69 years

Spot urine (SU) collection is a convenient method commonly used for sodium estimation, but its validity in predicting 24-h urinary sodium (24-hUNa) excretion has not been thoroughly evaluated among the general population. The aim of this study was to comprehensively assess the validity of eight existing methods in predicting 24-hUNa excretion by using SU samples among Chinese adults. We analyzed 1424 representative individuals aged 18 to 69 years. We compared the measured and estimated measurements of 24-hUNa at the population level by examining bias, the correlation, intraclass correlation coefficients (ICCs), receiver operating characteristic (ROC) curves and Bland–Altman plots and analyzed the relative and absolute differences and misclassification at the individual level. The bias for all methods was significant (all p < 0.001), among which the smallest bias was − 7.9 mmol for the Toft formula and the largest bias was − 53.8 mmol for the Mage formula. Correlation coefficients were all less than 0.380, all formulas exhibited an area under the ROC curve below 0.683, and the Bland–Altman plots indicated slightly high dispersion of the estimation biases at higher sodium levels regardless of the formula. The proportions of relative differences > 40% for the eight methods were all over one-third, the proportions of absolute differences > 51.3 mmol/24 h (3 g/day NaCl) were all over 40%, and the misclassification rates (7, 10, and 13 g/day NaCl as cutoff points) were all over 65%. Caution remains due to poor validity between estimated and actual measurements when using the eight formulas to obtain a plausible estimation for surveillance of the Chinese population sodium excretion, and the results do not support the application of SU to estimate sodium intake at the individual level due to its poor performance with respect to classification.

Spot Urine Protein Excretion in the First Year Following Kidney Transplantation Associates With Allograft Rejection Phenotype at 1-Year Surveillance Biopsies: An Observational National-Cohort Study

Introduction: Urine protein excretion is routinely measured to assess kidney allograft injury, but the diagnostic value of this measurement for kidney transplant pathology remains unclear. Here we investigated whether spot urine protein excretion in the first year following transplantation associates with allograft rejection phenotype at 1-year surveillance biopsies and de-novo occurrence of donor-specific antibodies (DSA).Patients and Methods: This prospective, observational national-cohort study included 139 non-sensitized patients who received a deceased donor kidney transplant between December 2014 and 2018. All patients received basiliximab induction and tacrolimus-based immunosuppression. Estimated protein excretion rate (ePER) was calculated monthly from spot urine protein-to-creatinine ratios. At 1-year, all recipients underwent surveillance graft biopsy and were screened for de-novo DSA. Screening-positive sera were subjected to single antigen bead (SAB) testing. The occurrence of de-novo DSA was determined based on SAB reactivity patterns using a mean fluorescence intensity threshold &gt;1,000.Results: Among the 139 study patients, 27 patients (19%) had histologic evidence of T cell-mediated rejection (TCMR), and 9 patients (7%) had histologic evidence of antibody-mediated rejection (AMR) at 1-year surveillance biopsy. One year after transplant, 19 patients (14%) developed de-novo DSA. Compared with patients without rejection and no de-novo DSA, mixed-effects linear regression analysis showed a significant difference in slope of ePER during the first year in patients with AMR and de-novo DSA at 1-year (46, 95% CI 25–68 mg/day/1.73 m2 per month and 34, 95% CI 20–49 mg/day/1.73 m2 per month, respectively). Patients with vascular TCMR also showed a significant difference in ePER slope over time compared with patients with non-rejection findings (31, 95% CI 9–52 mg/day/1.73 m2 per month). The discriminatory power of ePER for intragraft rejection processes was better in patients with AMR (AUC 0.95, 95% CI 0.90–0.99; P &lt; 0.001) than in those with TCMR (AUC 0.68, 95% CI 0.59–0.79; P = 0.002), with 89% sensitivity and 93% specificity for proteinuria &gt;550 mg/day/1.73m2.Conclusions: An increase in ePER in the first year following kidney transplantation associates with AMR, vascular TCMR and de-novo DSA at 1-year and may be used as a non-invasive clinical marker of intragraft endothelial cell injury.