Predicting urinary creatinine excretion and its usefulness to identify incomplete 24h urine collections

Studies using 24 h urine collections need to incorporate ways to validate the completeness of the urine samples. Models to predict urinary creatinine excretion (UCE) have been developed for this purpose; however, information on their usefulness to identify incomplete urine collections is limited. We aimed to develop a model for predicting UCE and to assess the performance of a creatinine index using para-aminobenzoic acid (PABA) as a reference. Data were taken from the European Food Consumption Validation study comprising two non-consecutive 24 h urine collections from 600 subjects in five European countries. Data from one collection were used to build a multiple linear regression model to predict UCE, and data from the other collection were used for performance testing of a creatinine index-based strategy to identify incomplete collections. Multiple linear regression (n 458) of UCE showed a significant positive association for body weight (ß = 0·07), the interaction term sex × weight (ß = 0·09, reference women) and protein intake (ß = 0·02). A significant negative association was found for age (ß = - 0·09) and sex (ß = - 3·14, reference women). An index of observed-to-predicted creatinine resulted in a sensitivity to identify incomplete collections of 0·06 (95 % CI 0·01, 0·20) and 0·11 (95 % CI 0·03, 0·22) in men and women, respectively. Specificity was 0·97 (95 % CI 0·97, 0·98) in men and 0·98 (95 % CI 0·98, 0·99) in women. The present study shows that UCE can be predicted from weight, age and sex. However, the results revealed that a creatinine index based on these predictions is not sufficiently sensitive to exclude incomplete 24 h urine collections

Bias in protein and potassium intake collected with 24-h recalls (EPIC-Soft) is rather comparable across European populations

Purpose: We investigated whether group-level bias of a 24-h recall estimate of protein and potassium intake, as compared to biomarkers, varied across European centers and whether this was influenced by characteristics of individuals or centers. Methods: The combined data from EFCOVAL and EPIC studies included 14 centers from 9 countries (n = 1,841). Dietary data were collected using a computerized 24-h recall (EPIC-Soft). Nitrogen and potassium in 24-h urine collections were used as reference method. Multilevel linear regression analysis was performed, including individual-level (e.g., BMI) and center-level (e.g., food pattern index) variables. Results: For protein intake, no between-center variation in bias was observed in men while it was 5.7% in women. For potassium intake, the between-center variation in bias was 8.9% in men and null in women. BMI was an important factor influencing the biases across centers (p <0.01 in all analyses). In addition, mode of administration (p = 0.06 in women) and day of the week (p = 0.03 in men and p = 0.06 in women) may have influenced the bias in protein intake across centers. After inclusion of these individual variables, between-center variation in bias in protein intake disappeared for women, whereas for potassium, it increased slightly in men (to 9.5%). Center-level variables did not influence the results. Conclusion: The results suggest that group-level bias in protein and potassium (for women) collected with 24-h recalls does not vary across centers and to a certain extent varies for potassium in men. BMI and study design aspects, rather than center-level characteristics, affected the biases across center

Cross-continental comparison of national food consumption survey methods—A narrative review

Food consumption surveys are performed in many countries. Comparison of results from those surveys across nations is difficult because of differences in methodological approaches. While consensus about the preferred methodology associated with national food consumption surveys is increasing, no inventory of methodological aspects across continents is available. The aims of the present review are (1) to develop a framework of key methodological elements related to national food consumption surveys, (2) to create an inventory of these properties of surveys performed in the continents North- America, South-America, Asia and Australasia, and (3) to discuss and compare these methodological properties cross-continentally. A literature search was performed using a fixed set of search terms in different databases. The inventory was completed with all accessible information from all retrieved publications and corresponding authors were requested to provide additional information where missing. Surveys from ten individual countries, originating from four continents are listed in the inventory. The results are presented according to six major aspects of food consumption surveys. The most common dietary intake assessment method used in food consumption surveys worldwide is the 24-HDR (24 h dietary recall), occasionally administered repeatedly, mostly using interview software. Only three countries have incorporated their national food consumption surveys into continuous national health and nutrition examination surveys

Kidney Function-Dependence of Vitamin K-Status Parameters:Results from the TransplantLines Biobank and Cohort Studies

High circulating dephosphorylated (dp) uncarboxylated (uc) matrix Gla protein (MGP) and uc osteocalcin (OC) concentrations are regarded as markers of vitamin K-deficiency. However, because MGP and OC are small molecules, they may potentially pass the glomerulus, and their blood concentrations may strongly depend on kidney function. However, many studies with vitamin K-status parameters do not structurally adjust for baseline kidney function, and detailed studies on kidney function-dependence of vitamin K-status markers are lacking. We therefore measured plasma dp-ucMGP using a chemiluminescent assay in 578 kidney transplant recipients (41% females, age 56 ± 13y, 7.5 (3.2 to 13.7)y after transplantation, eGFR 49 ± 17 mL/min/1.73 m(2)) participating in the prospective TransplantLines Cohort Studies. Additionally, dp-carboxylated MGP, ucOC and carboxylated OC were measured using ELISA in plasma of a subgroup of 60 participants. Finally, dp-ucMGP was measured in a separate cohort of 124 kidney transplant recipients before and three months after kidney transplantation. Dp-ucMGP positively correlated with creatinine, cystatin C, and negatively with eGFR (Spearman’s ρ 0.54, 0.60, and −0.54, respectively, p < 0.001 for all), and each 10 mL/min/1.73 m(2) increase in eGFR was associated with a 14.0% lower dp-ucMGP. Additionally, dp-ucMGP strongly declined after kidney transplantation (pretransplantation: 1252 (868 to 1744) pmol/L to posttransplantation: 609 (451 to 914) pmol/L, p < 0.001). Proportions of dp-ucMGP over total MGP and ucOC over total OC were not associated with eGFR. This study highlights that dp-ucMGP is strongly associated with kidney function, and that levels strongly decrease after kidney transplantation. We therefore propose adequate adjustment for kidney function, or the use of kidney function-independent parameters such as proportion of uncarboxylated MGP or OC in the assessment of vitamin K-status in clinical practice and research

Aorto-Iliac Artery Calcification and Graft Outcomes in Kidney Transplant Recipients

While the association of vascular calcification with inferior patient outcomes in kidney transplant recipients is well-established, the association with graft outcomes has received less attention. With this dual-centre cohort study, we aimed to determine the clinical impact of recipient pre-transplant aorto-iliac calcification, measured on non-contrast enhanced computed tomography (CT)-imaging within three years prior to transplantation (2005&ndash;2018). We included 547 patients (61.4% male, age 60 (interquartile range 51&ndash;68) years), with a median follow-up of 3.1 (1.4&ndash;5.2) years after transplantation. The aorto-iliac calcification score (CaScore) was inversely associated with one-year estimated-glomerular filtration rate (eGFR) in univariate linear regression analysis (standard &beta; &minus;3.3 (95% CI &minus;5.1 to &minus;1.5, p &lt; 0.0001), but not after adjustment for potential confounders, including donor and recipient age (p = 0.077). In multivariable Cox regression analyses, a high CaScore was associated with overall graft failure (p = 0.004) and death with a functioning graft (p = 0.002), but not with death-censored graft failure and graft function decline. This study demonstrated that pre-transplant aorto-iliac calcification is associated with one-year eGFR in univariate, but not in multivariable linear regression analyses. Moreover, this study underlines that transplantation in patients with a high CaScore does not result in earlier transplant function decline or worse death censored graft survival, although ongoing efforts for the prevention of death with a functioning graft remain essential

Aorto-Iliac Artery Calcification Prior to Kidney Transplantation

As vascular calcification is common in kidney transplant candidates, aorto-iliac vessel imaging is performed for surgical planning. The aim of the present study was to investigate whether a novel non-contrast enhanced computed tomography-based quantification technique for aorto-iliac calcification can be used for cardiovascular risk stratification prior to kidney transplantation. In this dual-center cohort study, we measured the aorto-iliac calcium score (CaScore) of 547 patients within three years prior to transplantation (2005-2018). During a median (interquartile range) follow-up of 3.1 (1.4, 5.2) years after transplantation, 80 (14.7%) patients died, of which 32 (40.0%) died due to cardiovascular causes, and 84 (15.5%) patients had a cardiovascular event. Kaplan-Meier survival curves showed significant differences between the CaScore tertiles for cumulative overall-survival (Log-rank testp<0.0001), cardiovascular survival (p<0.0001), and cardiovascular event-free survival (p<0.001). In multivariable Cox regression, the aorto-iliac CaScore was associated with all-cause mortality (hazard ratio 1.53, 95%CI 1.14-2.06,p= 0.005), cardiovascular mortality (2.04, 1.20-3.45,p= 0.008), and cardiovascular events (1.35, 1.01-1.80,p= 0.042). These independent associations of the aorto-iliac CaScore with the outcome measures can improve the identification of patients at risk for (cardiovascular) death and those who could potentially benefit from stringent cardiovascular monitoring to improve their prognosis after transplantation

Galectin-3 and Risk of Late Graft Failure in Kidney Transplant Recipients:A 10-year Prospective Cohort Study

Background. Galectin-3 may play a causal role in kidney inflammation and fibrosis, which may also be involved in the development of kidney graft failure. With novel galectin-3-targeted pharmacological therapies increasingly coming available, we aimed to investigate whether galectin-3 is associated with risk of late graft failure in kidney transplant recipients (KTR). Methods. We studied adult KTR who participated in TransplantLines Insulin Resistance and Inflammation Biobank and Cohort Study, recruited in a university setting (2001-2003). Follow-up was performed for a median of 9.5 (interquartile range, 6.2-10.2) years. Overall and stratified (P-interaction = 140 mmHg (HR, 2.29; 95% CI, 1.80-2.92; P < 0.001; P-interaction = 0.01) or smoking history (HR, 2.56; 95% CI, 1.95-3.37; P < 0.001; P-interaction = 0.03). Similarly, patients in the highest tertile of galectin-3 were consistently at increased risk of graft failure. Conclusions. Serum galectin-3 levels are elevated in KTR, and independently associated with increased risk of late graft failure. Whether galectin-3-targeted therapies may represent novel opportunities to decrease the long-standing high burden of late graft failure in stable KTR warrants further studies

Strongly coloured thiocyanate frameworks with perovskite-analogue structures

We report the first examples of thiocyanate-based analogues of the cyanide Prussian Blue compounds, MIII[Bi(SCN)6], M= Fe, Cr, Sc. These compounds adopt the primitive cubic pcu topology and show strict cation order. Optical absorption measurements show these compounds have band gaps within the visible and near IR region, suggesting that they may be useful for applications where light harvesting is key, such as photocatalysis. We also show that Cr[Bi(SCN)6] can reversibly uptake water into its framework structure pointing towards the possibility of using these frameworks for host/guest chemistry

Serum Calcification Propensity and the Risk of Cardiovascular and All-Cause Mortality in the General Population:The PREVEND Study

Objective: Vascular calcification contributes to the cause of cardiovascular disease. The calciprotein particle maturation time (T50) in serum, a measure of calcification propensity, has been linked with adverse outcomes in patients with chronic kidney disease, but its role in the general population is unclear. We investigated whether serum T50 is associated with cardiovascular mortality in a large general population-based cohort. Approach and Results: The relationship between serum T50 and cardiovascular mortality was studied in 6231 participants of the PREVEND (Prevention of Renal and Vascular End-Stage Disease) cohort. All-cause mortality was the secondary outcome. Mean (±SD) age was 53±12 years, 50% were male, and mean serum T50 was 329±58 minutes. A shorter serum T50 is indicative of a higher calcification propensity. Serum T50 was inversely associated with circulating phosphate, age, estimated glomerular filtration rate, and alcohol consumption, whereas plasma magnesium was positively associated with serum T50 (P&lt;0.001, total multivariable model R2=0.281). During median (interquartile range) follow-up for 8.3 (7.8-8.9) years, 364 patients died (5.8%), of whom 95 (26.1%) died from a cardiovascular cause. In multivariable Cox proportional hazard models, each 60 minutes decrease in serum T50 was independently associated with a higher risk of cardiovascular mortality (fully adjusted hazard ratio [95% CI], 1.22 [1.04-1.36], P=0.021). This association was modified by diabetes mellitus; stratified analysis indicated a more pronounced association in individuals with diabetes mellitus. Conclusions: Serum T50 is independently associated with an increased risk of cardiovascular mortality in the general population and thus may be an early and potentially modifiable risk marker for cardiovascular mortality.</p