BackgroundMounting evidence indicates that elevated serum uric acid may increase the incidence of chronic kidney disease (CKD). Our goal was to systematically evaluate longitudinal cohort studies for the association of serum uric acid levels and incident CKD.MethodsWe searched electronic databases and the reference lists of relevant articles. The primary outcome was incident CKD, which was defined as an eGFR less than 60 mL/min/1.73 m2 at the follow-up examination. Study-specific risk estimates were combined using random-effects models. The included studies were stratified into subgroups, and meta-regression analyses were performed.ResultsFifteen unique cohorts with a total of 99,205 individuals and 3,492 incident CKD cases were included. The relative risk of CKD was 1.22 (95% CI 1.16–1.28, I2 = 65.9%) per 1 mg/dL serum uric level increment. This positive association was consistently observed in subgroups stratified according to most of the study-level characteristics. The observed positive association was more pronounced among group with a mean age <60 years (RR 1.26, 95% CI 1.21–1.31), and low-level heterogeneity was observed in the findings for this age group (I2 = 46.4%, P = 0.022). However, no association was observed among studies with a mean age≥60 years (RR 1.04, 95% CI 0.96–1.13), and no evidence of heterogeneity was evident among the studies (I2 = 0%, P = 0.409). This mean age-related difference in the association between serum uric acid levels and CKD was significant (P = 0.004). The sensitivity analysis results were consistent when the analyses were restricted to studies that controlled for proteinuria and metabolic syndrome.ConclusionsOur meta-analysis demonstrated a positive association between serum uric acid levels and risk of CKD in middle-aged patients independent of established metabolic risk factors. Future randomized, high-quality clinical trials are warranted to determine whether lowering uric acid levels is beneficial in CKD.

Since 1 July 2018, the GRAPES (Global/Regional Assimilation and PrEdiction System) global 4‐dimensional variational (4D‐Var) data assimilation system has been in operation at the China Meteorological Administration (CMA). In this study, the GRAPES global 4D‐Var data assimilation system is comprehensively introduced. This system applies the non‐hydrostatic global tangent‐linear model (TLM) and the adjoint model (ADM) for the first time. The use of a digital filter as a weak constraint is achieved. A series of linear physical processes is developed, including vertical diffusion, subgrid‐scale orographic parametrization, large‐scale condensation, and cumulus convection parametrization. The vertical diffusion and subgrid‐scale orographic schemes are used in the operational suite and the linear convection parametrization and large‐scale condensation scheme remain under assessment. The Lanczos and conjugate gradient (Lanczos‐CG) algorithm and the limited‐memory Broyden‐Fletcher‐Goldfarb‐Shanno (L‐BFGS) algorithm are also developed. In terms of computational optimization, the total computational time of the GRAPES global TLM and ADM is approximately threefold that of the GRAPES global nonlinear model (NLM). Before it became operational, a one‐year retrospective trial was performed on the GRAPES global 4D‐Var data assimilation system. The entire system was stable, and the analysis and forecasting performances were significantly better than those of the 3D‐Var data assimilation system, especially in the Southern Hemisphere.

Many long-term maintenance hemodialysis patients have symptoms of protein-energy wasting caused by malnutrition. Each session of hemodialysis removes about 10 to 12 g of amino acids and 200 to 480 kcal of energy. Patients receiving hemodialysis for chronic kidney disease may be undernourished for energy, protein consumption, or both. Non-diabetic hemodialysis patients were randomized to three treatment groups: oral supplementation, oral supplementation plus high-concentration glucose solution (250 mL containing 50% glucose) and these two interventions plus 8.5% amino acids solution. The post-treatment energy status of the glucose group was significantly higher than its baseline level, whereas the control group’s status was significantly lower. The glucose group had significantly higher concentrations of asparagine, glutamine, glycine, alanine, and lysine after treatment. All treatment groups had significantly increased hemoglobin levels but significantly decreased transferrin levels after treatment compared to baseline. After treatment, the amino acid group had significantly higher albumin level compared to the glucose group (p = 0.001) and significantly higher prealbumin level compared to the control group (p = 0.017). In conclusion, long-term intervention with high-concentration glucose solution at each hemodialysis session is a simple and cheap method that replenished energy stores lost during hemodialysis of non-diabetic patients.

Background Different dialysis treatments may affect the composition and structure of the intestinal flora of dialysis-treated chronic kidney disease (CKD) patients. This study aimed to analyze the correlations between the different flora and the nutritional indexes and further explore the potential metabolic pathways in patients with CKD in end-stage renal disease (ESRD). Methods Altogether, 102 patients with ESRD were recruited and categorized into the hemodialysis (HD) group (N = 49) and the peritoneal dialysis (PD) group (N = 53). Their biochemical indexes, anthropometric indicators, and inflammatory markers were determined. The total genomic DNA was extracted for 16S ribosomal DNA sequencing. Furthermore, bioinformatics analysis was employed for functional analysis. Results Anthropometric indicators, including handgrip strength, mid-upper arm circumference, mid-upper arm muscle circumference, and body mass index, in the HD and PD groups showed a positive correlation with butyric acid-producing bacteria (Rosella and Phascolarctobacterium) and a negative correlation with conditional pathogens (Escherichia spp.). Meanwhile, the inflammatory markers, including high-sensitivity C-reactive protein and interleukin-6, were significantly higher in the PD-protein–energy wasting (PEW) group than in the PD-non-protein–energy wasting (NPEW) group; although they showed an increasing trend in the HD-PEW group, no significant difference was noted. Rosella was considerably scarce in the HD-PEW group than in the HD-NPEW group, whereas Escherichia was substantially more abundant in the PD-PEW group than in the PD-NPEW group. Compared with the HD group, the essential amino acid synthesis pathway, amino acid metabolism-related enzyme pathways, and aminoacyl-transfer RNA biosynthesis pathways were weakened in the PD group. Most carbohydrate metabolic pathways were weakened, although the tricarboxylic acid cycle was slightly enhanced. Concurrently, the fatty acid metabolism was enhanced, whereas fatty acid synthesis was weakened; the metabolic pathways of B vitamins were also weakened. These potential metabolic pathways of the various compounds released by intestinal flora showed a significant correlation with blood biochemical indexes, anthropometric indicators, and inflammatory markers. Conclusion In patients with ESRD, different dialysis treatments affected the abundance of butyric acid-producing bacteria (Rosella and Phascolarctobacterium) and conditional pathogens (Escherichia spp.). Butyric acid-producing bacteria showed a positive correlation with PEW and showed a negative correlation with Escherichia. Improving the intestinal diversity and increasing the amount of butyric acid-producing bacteria, such as Blautella, Faecococcus, and Phascolarctobacterium, are potential therapeutic approaches to enhance protein–energy consumption in patients with ESRD.

No abstract