Cut-off values of haemoglobin and clinical outcomes in incident peritoneal dialysis: the PDTAP study.

BACKGROUND: To explore the cut-off values of haemoglobin (Hb) on adverse clinical outcomes in incident peritoneal dialysis (PD) patients based on a national-level database. METHODS: The observational cohort study was from the Peritoneal Dialysis Telemedicine-assisted Platform (PDTAP) dataset. The primary outcomes were all-cause mortality, major adverse cardiovascular events (MACE) and modified MACE (MACE+). The secondary outcomes were the occurrences of hospitalization, first-episode peritonitis and permanent transfer to haemodialysis (HD). RESULTS: A total of 2591 PD patients were enrolled between June 2016 and April 2019 and followed up until December 2020. Baseline and time-averaged Hb <100 g/l were associated with all-cause mortality, MACE, MACE+ and hospitalizations. After multivariable adjustments, only time-averaged Hb <100 g/l significantly predicted a higher risk for all-cause mortality {hazard ratio [HR] 1.83 [95% confidence interval (CI) 1.19-281], P = .006}, MACE [HR 1.99 (95% CI 1.16-3.40), P = .012] and MACE+ [HR 1.77 (95% CI 1.15-2.73), P = .010] in the total cohort. No associations between Hb and hospitalizations, transfer to HD and first-episode peritonitis were observed. Among patients with Hb ≥100 g/l at baseline, younger age, female, use of iron supplementation, lower values of serum albumin and renal Kt/V independently predicted the incidence of Hb <100 g/l during the follow-up. CONCLUSION: This study provided real-world evidence on the cut-off value of Hb for predicting poorer outcomes through a nation-level prospective PD cohort.

Dissecting the colocalized GWAS and eQTLs with mediation analysis for high-dimensional exposures and confounders.

To leverage the advancements in genome-wide association studies (GWAS) and quantitative trait loci (QTL) mapping for traits and molecular phenotypes to gain mechanistic understanding of the genetic regulation, biological researchers often investigate the expression QTLs (eQTLs) that colocalize with QTL or GWAS peaks. Our research is inspired by 2 such studies. One aims to identify the causal single nucleotide polymorphisms that are responsible for the phenotypic variation and whose effects can be explained by their impacts at the transcriptomic level in maize. The other study in mouse focuses on uncovering the cis-driver genes that induce phenotypic changes by regulating trans-regulated genes. Both studies can be formulated as mediation problems with potentially high-dimensional exposures, confounders, and mediators that seek to estimate the overall indirect effect (IE) for each exposure. In this paper, we propose MedDiC, a novel procedure to estimate the overall IE based on difference-in-coefficients approach. Our simulation studies find that MedDiC offers valid inference for the IE with higher power, shorter confidence intervals, and faster computing time than competing methods. We apply MedDiC to the 2 aforementioned motivating datasets and find that MedDiC yields reproducible outputs across the analysis of closely related traits, with results supported by external biological evidence. The code and additional information are available on our GitHub page (https://github.com/QiZhangStat/MedDiC).

Data-driven identification of SARS-CoV-2 subpopulations using PhenoGraph and binary-coded genomic data.

For epidemic prevention and control, the identification of SARS-CoV-2 subpopulations sharing similar micro-epidemiological patterns and evolutionary histories is necessary for a more targeted investigation into the links among COVID-19 outbreaks caused by SARS-CoV-2 with similar genetic backgrounds. Genomic sequencing analysis has demonstrated the ability to uncover viral genetic diversity. However, an objective analysis is necessary for the identification of SARS-CoV-2 subpopulations. Herein, we detected all the mutations in 186 682 SARS-CoV-2 isolates. We found that the GC content of the SARS-CoV-2 genome had evolved to be lower, which may be conducive to viral spread, and the frameshift mutation was rare in the global population. Next, we encoded the genomic mutations in binary form and used an unsupervised learning classifier, namely PhenoGraph, to classify this information. Consequently, PhenoGraph successfully identified 303 SARS-CoV-2 subpopulations, and we found that the PhenoGraph classification was consistent with, but more detailed and precise than the known GISAID clades (S, L, V, G, GH, GR, GV and O). By the change trend analysis, we found that the growth rate of SARS-CoV-2 diversity has slowed down significantly. We also analyzed the temporal, spatial and phylogenetic relationships among the subpopulations and revealed the evolutionary trajectory of SARS-CoV-2 to a certain extent. Hence, our results provide a better understanding of the patterns and trends in the genomic evolution and epidemiology of SARS-CoV-2.

Cardiac arrest as initial presentation of pheochromocytoma in a young.

We reported a case of pheochromocytoma with initial presentation of cardiac arrest. The patient underwent implantable cardioverter defibrillator for primary prevention but subsequently experienced repeated implantable cardioverter defibrillator shocks and syncopal episodes. A mass was found in the adrenal gland by CT, which was confirmed by anatomopathological analysis of the surgical specimen.

Integrating the flow regime and water quality effects into a niche-based metacommunity dynamics model for river ecosystems.

Aquatic community dynamics are closely dominated by flow regime and water quality conditions, which are increasingly threatened by dam regulation, water diversion, and nutrition pollution. However, further understanding of the ecological impacts of flow regime and water quality conditions on aquatic multi-population dynamics has rarely been integrated into existing ecological models. To address this issue, a new niche-based metacommunity dynamics model (MDM) is proposed. The MDM aims to simulate the coevolution processes of multiple populations under changing abiotic environments, pioneeringly applied to the mid-lower Han River, China. The quantile regression method was used for the first time to derive ecological niches and competition coefficients of the MDM, which are demonstrated to be reasonable by comparing them with the empirical evidence. Simulation results show that the Nash efficiency coefficients for fish, zooplankton, zoobenthos, and macrophytes are more than 0.64, while the Pearson correlation coefficients for them are no less than 0.71. Overall, the MDM performs effectively in simulating metacommunity dynamics. For all river stations, the average contributions of biological interaction, flow regime effects, and water quality effects to multi-population dynamics are 64%, 21%, and 15%, respectively, suggesting that the population dynamics are dominated by biological interaction. For upstream stations, the fish population is 8%-22% more responsive to flow regime alteration than other populations, while other populations are 9%-26% more responsive to changes in water quality conditions than fish. For downstream stations, flow regime effects on each population account for less than 1% due to more stable hydrological conditions. The innovative contribution of this study lies in proposing a multi-population model to quantify the effects of flow regime and water quality on aquatic community dynamics by incorporating multiple indicators of water quantity, water quality, and biomass. This work has potential for the ecological restoration of rivers at the ecosystem level. This study also highlights the importance of considering threshold and tipping point issues when analyzing the "water quantity-water quality-aquatic ecology" nexus in future works.

Transcriptome analysis reveals gene expression changes of the basidiomycetous yeast Apiotrichum mycotoxinivorans in response to ochratoxin A exposure.

Ochratoxin A (OTA) is one of the most common and deleterious mycotoxins found in food and feedstuffs worldwide; however, Apiotrichum mycotoxinivorans can detoxify OTA. Our results show that A. mycotoxinivorans GUM1709 efficiently degraded OTA, but it caused the accumulation of intracellular reactive oxygen species. The main aim of this study was to identify potential OTA-detoxifying enzymes and to explore the effects of OTA on A. mycotoxinivorans GMU1709. RNA-seq data revealed that 1643 and 1980 genes were significantly upregulated and downregulated, respectively, after OTA exposure. Functional enrichment analyses indicated that OTA exposure enhanced defense capability, protein transport, endocytosis, and energy metabolism; caused ribosomal stress; suppressed DNA replication and transcription; inhibited cell growth and division; and promoted cell death. The integration of secretome, gene expression, and molecular docking analyses revealed that two carboxypeptidase homologues (members of the metallocarboxypeptidase family) were most likely responsible for the detoxification of both extracellular and intracellular OTA. Superoxide dismutase and catalase were the main genes activated in response to oxidative stress. In addition, analysis of key genes associated with cell division and apoptosis showed that OTA exposure inhibited mitosis and promoted cell death. This study revealed the possible OTA response and detoxification mechanisms in A. mycotoxinivorans.

Transcriptomic responses of the zearalenone (ZEN)-detoxifying yeast Apiotrichum mycotoxinivorans to ZEN exposure.

Zearalenone (ZEN) is a potent oestrogenic mycotoxin that is mainly produced by Fusarium species and is a serious environmental pollutant in animal feeds. Apiotrichum mycotoxinivorans has been widely used as a feed additive to detoxify ZEN. However, the effects of ZEN on A. mycotoxinivorans and its detoxification mechanisms remain unclear. In this study, transcriptomic and bioinformatic analyses were used to investigate the molecular responses of A. mycotoxinivorans to ZEN exposure and the genetic basis of ZEN detoxification. We detected 1424 significantly differentially expressed genes (DEGs), of which 446 were upregulated and 978 were downregulated. Functional and enrichment analyses showed that ZEN-induced genes were significantly associated with xenobiotic metabolism, oxidative stress response, and active transport systems. However, ZEN-inhibited genes were mainly related to cell division, cell cycle, and fungal development. Subsequently, bioinformatic analysis identified candidate ZEN-detoxification enzymes. The Baeyer-Villiger monooxygenases and carboxylesterases, which are responsible for the formation and subsequent hydrolysis of a new ZEN lactone, respectively, were significantly upregulated. In addition, the expression levels of genes related to conjugation and transport involved in the xenobiotic detoxification pathway were significantly upregulated. Moreover, the expression levels of genes encoding enzymatic antioxidants and those related to growth and apoptosis were significantly upregulated and downregulated, respectively, which made it possible for A. mycotoxinivorans to survive in a highly toxic environment and efficiently detoxify ZEN. This is the first systematic report of ZEN tolerance and detoxification in A. mycotoxinivorans. We identified the metabolic enzymes that were potentially involved in detoxifying ZEN in the GMU1709 strain and found that ZEN-induced transcriptional regulation of genes is key to withstanding highly toxic environments. Hence, our results provide valuable information for developing enzymatic detoxification systems or engineering this detoxification pathway in other species.

HomeMonitor: An Enhanced Device Event Detection Method for Smart Home Environment.

As more and more smart devices are deployed in homes, the communication between these smart home devices and elastic computing services may face some risks of privacy disclosure. Different device events (such as the camera on, video on, etc.) will generate different data traffic during communication. However, the current smart home system lacks monitoring of these device events, which may cause the disclosure of private data collected by these devices. In this paper, we present our device event monitor system, HomeMonitor. HomeMonitor runs in the OpenWRT system and supports complete event monitoring for smart home devices. HomeMoitor solves the problem that machine learning models for detecting device events do not scale flexibly. It uses the network packet size and the direction of the device event for unique identification during training. When detecting, it only needs to get the packet size and timestamp and then query the policy table for signature matching to control the device events. We evaluated the effectiveness of HomeMonitor, and the experiments show that the match rate of our method is 98.8%, the false positive rate is 1.8%, and the detection time is only 16.67% for PINBALL. The results mean that our method achieves the balance of applicable protocol scope, detection performance, and detection accuracy.

LncRNA TLR8-AS1 suppresses miR-34a maturation in hepatocellular carcinoma to suppress cell proliferation and migration.

TLR8-AS1 has been characterized as an oncogenic lncRNA in ovarian cancer, while its role in hepatocellular carcinoma (HCC) is unknown. This study aimed to explore the role of TLR8-AS1 in HCC. TLR8-AS1 expression in HCC and paired non-tumor tissues from 62 HCC patients was determined by RT-qPCR. The prognostic value of TLR8-AS1 for HCC was analyzed by performing a 5-year follow-up. Correlations between TLR8-AS1 and mature miR-34a and miR-34a precursor were analyzed by Pearson's correlation coefficient. The roles of TLR8-AS1 and miR-34a in regulating the proliferation and migration were explored by CCK-8 assay and Transwell migration assay. We found that TLR8-AS1 was upregulated in HCC and predicted poor survival. Across HCC tissues, TLR8-AS1 was inversely correlated with mature miR-34a, but not miR-34a precursor. In HCC cells, TLR8-AS1 overexpression downregulated mature miR-34a, but not miR-34a precursor. Cell proliferation and Transwell migration assay showed that TLR8-AS1 overexpression reduced the enhancing effects of miR-34a on cell proliferation and migration. TLR8-AS1 may suppress miR-34a maturation in HCC to suppress cell proliferation and migration.

Identification of docetaxel-related biomarkers for prostate cancer.

Prostate cancer (PCa) which was the second commonly diagnosed malignancy, contributed to the top fifth carcinoma death in men. Nevertheless, the main chemotherapeutic agent docetaxel came to failure due to chemoresistance. Recently, increasing evidence suggested the importance of tumour microenvironment (TME) in PCa. The present study aimed to explore the specific TME in PCa and find biomarkers related to both immune infiltration and docetaxel. The docetaxel-specific genes and differential expression genes comparing PCa with normal control samples were derived using DESeq2 and zinbwave with GSE140440, TCGA and GTEx datasets. Immune-infiltration-related genes were identified using CIBERSORT and co-expression network analysis. Key genes related to both docetaxel and immune infiltrating in PCa, including nine genes, namely ZNF486, IFI6, TMOD2, HSPA4L, ITPR1, LRRC37A7P, APOC1, APOBEC3G, and ITGA2, were determined by overlapping above three gene sets. ITGA2 was then defined as the hub gene for its significant prognostic implications. Further validations conducted on Oncomine, GEO, TISIDB, MSigDB, and The Human Protein Atlas confirmed the docetaxel-specific and immune infiltrating characteristics of ITGA2. To sum up, our findings could provide a better understanding of immune infiltrating and docetaxel-resistance in PCa, mostly, ITGA2 could serve as potential prognosis biomarkers and targets for the combination of docetaxel.

Pan-genomic analysis provides novel insights into the association of E.coli with human host and its minimal genome.

MOTIVATION: Bacteria can usually acquire certain advantageous genes that enable the bacteria to adapt to rapidly changing niches, thereby leading to a wide range of intraspecific genome content and genetic redundancy. The minimal genome of Escherichia coli, which is the most important bacterial species, and the association between E.coli and its human host are worthy of further exploration. RESULTS: We used gene prediction and phylogenetic analysis to reveal a rich phylogenetic diversity among 491 E.coli strains and to reveal substantial differences between these strains with respect to gene number and genome length. We used pan-genomic analysis to accurately identify 867 core genes, in which only 243 genes are shared by essential genes. This analysis revealed that core genes mainly provide essential functions to the basic lifestyle of E.coli, and accessory genes are likely to confer selective advantages such as niche adaptation or the ability to colonize specific hosts. By association analysis, we found that E.coli strains in non-human hosts may more easily utilize foreign genetic materials to adapt to their surroundings, but the population in human hosts has higher demands for the control of population density, indicating that highly accurate quorum-sensing behavior is very important for harmony between E.coli and its human host. By considering core genes and previous deletions together, we proposed a potential direction for further reduction of the E.coli genome. AVAILABILITY AND IMPLEMENTATION: The data, analysis process and detailed information on software tools used in this study are all available in the supplementary material. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Prevention of peritoneal dialysis-related peritonitis by regular patient retraining via technique inspection or oral education: a randomized controlled trial.

BACKGROUND: There has been little research on strategies for prevention of peritoneal dialysis (PD)-related peritonitis. We explored whether regular retraining on bag exchanges (via two methods: technique inspection and oral education) every other month could help reduce the risk of peritonitis in PD patients through a randomized controlled trial (RCT). METHOD: This is an RCT conducted at Peking University First Hospital. A total of 150 incident patients receiving PD at our centre were included between December 2010 and June 2016 and followed up until June 2018. Patients were randomly assigned 1:1:1 to receive retraining on bag exchange via technique inspection, oral education or usual care. The primary outcome was time to the first peritonitis episode. Secondary outcomes were time to organism-specific peritonitis, transfer to haemodialysis and all-cause death. RESULTS: Patients in the technique inspection group, oral education group and usual care group (n = 50 for each group) were followed up for 47.5 ± 22.9 months. Time to first peritonitis was comparable between the groups. The technique inspection group showed a lower risk of first non-enteric peritonitis than the usual care group, while the oral education group did not show a significant benefit. The incidence of first non-enteric peritonitis in the usual care group (0.07/patient-year) was significantly higher than that in the technique inspection group (0.02/patient-year; P < 0.01) but was comparable with that in the oral education group (0.06/patient-year). Transfer to haemodialysis and all-cause mortality were not significantly different between the groups. CONCLUSIONS: Neither technique inspection nor oral education significantly altered the risk of all-cause peritonitis compared with usual care, despite technique inspection showing a trend towards reducing the risk of non-enteric PD-related peritonitis. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01621997).

Eosinophilic peritonitis and nephrotic syndrome in Kimura's disease: a case report and literature review : Eosinophilic peritonitis in Kimura's disease.

BACKGROUND: Eosinophilic peritonitis is a relatively rare entity. Kimura's disease is a rare chronic inflammatory disorder of unknown etiology, characterized by subcutaneous nodules mainly in the head and neck region, regional lymphadenopathy and occasional involvement of kidney. There is currently no report of eosinophilic peritonitis in Kimura's disease. CASE PRESENTATION: A 44-year-old Chinese man presented with abdominal distention, nausea, vomiting and edema in lower limbs for 1 month. Laboratory data showed elevated eosinophils in peripheral blood and ascites, nephrotic syndrome with progressively renal dysfunction, and elevated IgE. Ultrasonography of lymph nodes showed multiple lymphadenopathy in bilateral inguinal regions. Surgical excision was performed for one of the enlarged lymph nodes and histopathology revealed diagnosis of Kimura's disease. Renal biopsy indicated focal segmental glomerulosclerosis (FSGS) and acute tubulointerstitial nephritis with infiltration of eosinophils in renal interstitium. The patient was prescribed with oral prednisolone therapy (30 mg/day), and underwent continuous ambulatory peritoneal dialysis (CAPD). The peripheral and peritoneal eosinophil count decreased rapidly and normalized within 2 days. Forty-five days after prednisolone therapy, partial remission of nephrotic syndrome and decrease of serum creatinine were achieved while peritoneal dialysis dosage had decreased. Inguinal lymph nodes gradually shrunk in size. The overall conditions remain stable afterwards. CONCLUSIONS: This rare case highlighted the clinical conundrum of a patient presenting with eosinophilic peritonitis, lymphadenopathy, nephrotic syndrome and renal failure associated with Kimura's disease. The remarkable eosinophilia, pathology of lymph node and kidney, as well as significant response to steroids should guide towards the diagnosis.

The systematic analysis of ultraconserved genomic regions in the budding yeast.

Motivation: In the evolution of species, a kind of special sequences, termed ultraconserved sequences (UCSs), have been inherited without any change, which strongly suggests those sequences should be crucial for the species to survive or adapt to the environment. However, the UCSs are still regarded as mysterious genetic sequences so far. Here, we present a systematic study of ultraconserved genomic regions in the budding yeast based on the publicly available genome sequences, in order to reveal their relationship with the adaptability or fitness advantages of the budding yeast. Results: Our results indicate that, in addition to some fundamental biological functions, the UCSs play an important role in the adaptation of Saccharomyces cerevisiae to the acidic environment, which is backed up by the previous observation. Besides that, we also find the highly unchanged genes are enriched in some other pathways, such as the nutrient-sensitive signaling pathway. To facilitate the investigation of unique UCSs, the UCSC Genome Browser was utilized to visualize the chromosomal position and related annotations of UCSs in S.cerevisiae genome. Availability and implementation: For more details on UCSs, please refer to the Supplementary information online, and the custom code is available on request. Contact: fgao@tju.edu.cn. Supplementary information: Supplementary data are available at Bioinformatics online.

Recombinational DSBs-intersected genes converge on specific disease- and adaptability-related pathways.

Motivation: The budding yeast Saccharomyces cerevisiae is a model species powerful for studying the recombination of eukaryotes. Although many recombination studies have been performed for this species by experimental methods, the population genomic study based on bioinformatics analyses is urgently needed to greatly increase the range and accuracy of recombination detection. Here, we carry out the population genomic analysis of recombination in S.cerevisiae to reveal the potential rules between recombination and evolution in eukaryotes. Results: By population genomic analysis, we discover significantly more and longer recombination events in clinical strains, which indicates that adverse environmental conditions create an obviously wider range of genetic combination in response to the selective pressure. Based on the analysis of recombinational double strand breaks (DSBs)-intersected genes (RDIGs), we find that RDIGs significantly converge on specific disease- and adaptability-related pathways, indicating that recombination plays a biologically key role in the repair of DSBs related to diseases and environmental adaptability, especially the human neurological disorders. By evolutionary analysis of RDIGs, we find that the RDIGs highly prevailing in populations of yeast tend to be more evolutionarily conserved, indicating the accurate repair of DSBs in these RDIGs is critical to ensure the eukaryotic survival or fitness. Supplementary information: Supplementary data are available at Bioinformatics online.

Sleep Disorders and Cognitive Impairment in Peritoneal Dialysis: A Multicenter Prospective Cohort Study.

BACKGROUND: Patients with chronic kidney disease experience a high burden of sleep disorders, and there are associations between sleep disorders and cognitive impairment. OBJECTIVES: Based on our previous cross-sectional survey on cognitive impairment in peritoneal dialysis, we further explored the relationship between sleep disorders and cognitive impairment, and predictors for declining cognitive function. METHOD: We conducted a multicenter prospective cohort study enrolling 458 clinically stable patients on peritoneal dialysis who were then followed up for 2 years.Demographic data, comorbidities, depression, and biochemistry data were collected at baseline. Sleep disorders including insomnia, restless legs syndrome, sleep apnea syndrome, excessive daytime sleepiness, possible narcolepsy, sleep walking and nightmares, and possible rapid eye movement behavior disorders were assessed using a panel of specific sleep questionnaires at baseline and in a second survey. Global cognitive function was measured at baseline and in a second survey, using the Modified Mini-Mental State Examination. Specific cognitive domains were evaluated using Trail-Making Test Forms A and B for executive function, and subtests of the Battery for the Assessment of Neuropsychological Status were used to asses immediate and delayed memory, visuospatial skills, and language ability. RESULTS: Sleep disorders were common among peritoneal dialysis patients. The prevalence of cognitive impairment evaluated by the Modified Mini-Mental State Examination (3MS) increased from 19.8 to 23.9%. Possible narcolepsy was associated with decreased Modified Mini-Mental State Examination scores at baseline. During follow-up, sleepwalking and nightmares were associated with higher risks of declined delayed memory in the longitudinal study. CONCLUSIONS: Possible narcolepsy was associated with general cognitive dysfunction, and sleep walking and nightmares were risk factors for impaired delayed memory.

Cognitive Changes in Peritoneal Dialysis Patients: A Multicenter Prospective Cohort Study.

RATIONALE & OBJECTIVE: Cognitive impairment is an independent predictor of technique failure and mortality in patients on peritoneal dialysis (PD) therapy. We investigated changes in cognitive function and factors associated with it in this population. STUDY DESIGN: Multicenter prospective cohort study. SETTING & PARTICIPANTS: 458 PD patients were enrolled and followed up for 2 years. PREDICTORS: Global and specific domains of cognitive function were measured at baseline and after 2 years. The Modified Mini-Mental State Examination (3MS) was used for assessment of global cognitive function; Trail-Making Tests A and B, for executive function; and subtests of the Battery for the Assessment of Neuropsychological Status, for immediate and delayed memory, visuospatial skill, and language ability. OUTCOMES: The primary outcome was change in cognitive function. Secondary outcomes included all-cause mortality, cardiovascular mortality, hospitalization, and transition to hemodialysis therapy. ANALYTICAL APPROACH: Multivariable linear regression models. RESULTS: The prevalence of cognitive impairment increased from 19.8% to 23.9%. 3MS scores significantly decreased (84.8 to 83.1), although executive function, immediate memory, and visuospatial skill improved over time. Delayed memory capacity and language ability were unchanged. Lower serum albumin level was associated with deteriorated delayed memory, visuospatial skill, and language ability, as well as with the decline in general cognitive function (ß values of 0.64, 0.90, 0.80, and 0.44, respectively). Advanced age, lower education, and depression were also correlated with deterioration in general and specific cognitive function. After multivariable adjustment, both global and specific cognitive impairment at baseline were associated with a greater rate of hospitalization, and memory dysfunction was associated with a lower dialysis modality survival rate. LIMITATIONS: A relatively short observation period, small number of deaths, and potential selection bias due to patients unavailable for the second assessment. CONCLUSIONS: In a PD population, global cognitive function declined over 2 years, though some specific cognitive domains improved. Besides well-recognized factors, hypoalbuminemia and depression were also risk factors for cognitive impairment.

Novel Equations for Estimating Lean Body Mass in Patients With Chronic Kidney Disease.

OBJECTIVE: Simplified methods to estimate lean body mass (LBM), an important nutritional measure representing muscle mass and somatic protein, are lacking in nondialyzed patients with chronic kidney disease (CKD). We developed and tested 2 reliable equations for estimation of LBM in daily clinical practice. DESIGN AND METHODS: The development and validation groups both included 150 nondialyzed patients with CKD Stages 3 to 5. Two equations for estimating LBM based on mid-arm muscle circumference (MAMC) or handgrip strength (HGS) were developed and validated in CKD patients with dual-energy x-ray absorptiometry as referenced gold method. RESULTS: We developed and validated 2 equations for estimating LBM based on HGS and MAMC. These equations, which also incorporated sex, height, and weight, were developed and validated in CKD patients. The new equations were found to exhibit only small biases when compared with dual-energy x-ray absorptiometry, with median differences of 0.94 and 0.46 kg observed in the HGS and MAMC equations, respectively. Good precision and accuracy were achieved for both equations, as reflected by small interquartile ranges in the differences and in the percentages of estimates that were 20% of measured LBM. The bias, precision, and accuracy of each equation were found to be similar when it was applied to groups of patients divided by the median measured LBM, the median ratio of extracellular to total body water, and the stages of CKD. CONCLUSIONS: LBM estimated from MAMC or HGS were found to provide accurate estimates of LBM in nondialyzed patients with CKD.