Chronic kidney disease (CKD) management has evolved from supportive care with renin-angiotensin system inhibitors (RASi) alone to multi-target combination therapies. While RASi remain foundational, their limited efficacy in fully preventing disease progression (e.g. residual albuminuria) and safety concerns, such as hyperkalemia, have underscored the need for novel therapeutic agents. Sodium-glucose cotransporter-2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor agonists (GLP-1RA) and nonsteroidal mineralocorticoid receptor antagonists (nsMRA) demonstrate complementary nephroprotective effects by targeting metabolic, hemodynamic and inflammatory pathways within the cardiovascular-kidney-metabolic (CKM) syndrome framework. Evidence from large-scale studies demonstrates that combination four-pillar therapies are superior to monotherapy in reducing the risk of kidney failure in patients with diabetes and also exhibit complementary safety profiles that enhance tolerability and long-term patient adherence. For example, combining SGLT2i with RASi mitigates hyperkalemia risk and reduces RASi discontinuation, thereby enhancing treatment persistence. The KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD emphasizes patient-centered, team-based management integrating these therapies. Future directions include expanding evidence for non-diabetic CKD populations, more rapid implementation of these four-pillar therapies and new therapies such as aldosterone synthase inhibitors in this vulnerable group.

Background. Body roundness index (BRI), an emerging anthropometric measure, has been shown to outperform body mass index (BMI) in predicting mortality risk in the general population. However, its prognostic value among patients with chronic kidney disease (CKD), where the obesity paradox may exist, remains unknown. Methods. This observational study utilized data from the National Health and Nutrition Examination Survey. BRI was calculated using waist circumference (WC) and height, whereas BMI was calculated using body weight and height. Restricted cubic splines (RCSs) were applied to determine optimal cut-off points of BRI for all-cause and cardiovascular mortality in patients with CKD. Associations were examined using Cox proportional hazards models adjusted for potential confounders. Results. Over a median follow-up of 6.6 years, 6240 patients with CKD (mean age 63 years, 43% men) were included, with 1922 all-cause and 715 cardiovascular deaths recorded. RCSs demonstrated J-shaped associations between BRI with mortality. A BRI >10 was associated with a significantly increased risk of all-cause {adjusted hazard ratio [aHR] 1.82 [95% confidence interval (CI) 1.34-2.47]} and cardiovascular mortality [aHR 2.15 (95% CI 1.27-3.62)] compared with the reference of 5.9-6.8 and 5.9-6.5, respectively, with dose-response trends (P for trend < .05). A BMI >30 was paradoxically associated with 44% and 40% lower risks of all-cause and cardiovascular mortality compared with the reference of 18.5-25, respectively. A WC >125 was associated with an increased risk of all-cause mortality [aHR 2.17 (95% CI 1.47-3.18)] but not with cardiovascular mortality [aHR 1.83 (95% CI 0.97-3.45)] compared with the reference of 95-105 cm. The associations between BRI >10 and mortality risks were particularly pronounced among younger adults <65 years of age or individuals with elevated albuminuria (P for interaction < .05). Conclusions. Higher BRI was independently associated with increased all-cause and cardiovascular mortality risk among patients with CKD, offering greater prognostic value for risk stratification than BMI or WC.

Cardiovascular disease (CVD), chronic kidney disease (CKD), diabetes, and obesity frequently coexist and share overlapping pathophysiological mechanisms, contributing to poor health outcomes and high mortality. Recognising this interaction, the cardiovascular-kidney-metabolic (CKM) syndrome has been proposed to advance and unify the concepts of cardiorenal syndrome and metabolic syndrome. CKM syndrome is staged from 0 to 4, reflecting disease progression tracking and risk stratification, and emphasizes life-course screening to detect early metabolic and kidney abnormalities. Early identification of albuminuria and reduced kidney function, even in youth with metabolic risk factors, may slow CKD progression and reduce long-term complications. Further development and validation of risk prediction tools for major cardiovascular and kidney failure events in patients with CKM will help to guide individual therapeutic intervention. For nephrologists, this paradigm offers an opportunity to be involved in the interdisciplinary care model. In the future CKM care model, it would be ideal to have dedicated CKM coordinators in place to enhance collaboration between primary care and all the other specialties involved to improve outcomes, and reduce the global burden of CKM syndrome.

Cardiovascular disease and infections significantly contribute to high mortality and morbidity in patients with chronic kidney disease (CKD). Despite extensive research on cardiovascular complications, infection-related aspects in CKD have received limited attention. This review systematically synthesizes current evidence on the causes and consequences of infections in CKD patients. We focus on immunodeficiency as a primary factor in increased infection susceptibility and examine the clinical outcomes associated with infections in this population. Regarding causes, CKD patients exhibit heightened vulnerability to infections for secondary immunodeficiency related to kidney disease (SIDKD). Regarding its consequences, we review studies on the association between reduced kidney function and adverse outcomes, including hospitalizations, acute kidney injury, cardiovascular events, progression to end-stage kidney disease, infections caused by multidrug-resistant organisms. Infections in CKD patients are associated with increased mortality across different infection types. Infection-related complications are a critical concern in CKD management. We recommend further research to develop effective preventive strategies, including potential interventions involving Chinese medicine, to reduce infection risks in this high-risk population.

Non-cystic fibrosis bronchiectasis is associated with frequent and diverse microbial infections, yet an overall understanding of microbial presence across different disease stages is lacking. A meta-analysis assessed lung microbes in adults with non-CF bronchiectasis, collecting data using both culture-based and sequencing approaches through three international databases and three Chinese databases. Subgroups were categorized by disease stage: the stable group (S), the exacerbation group (E), and unclassified data consolidated into the undetermined group (U). Culture data were analysed in random-effects meta-analyses while sequencing data were processed using QIIME 2. A total of 98 studies were included with data from 54,384 participants worldwide. Pseudomonas aeruginosa was the most frequently isolated bacterium (S: 26[19–34]

Anemia is common in patients with heart failure (HF). Although iron testing is recommended, it is uncertain that solely emphasizing iron testing could result in lesser attention to other causes, like bleeding or cancer. This study aimed to evaluate the diagnostic work-up of incident anemia in patients with HF in routine care and associated health outcomes. Observational study of 8932 non-anemic adults with HF in Stockholm, Sweden, was quantified for incidence of anemia, diagnostic work-up (recognition, laboratory/invasive testing) and treatment across severity of anemia and setting of care. Time-varying Cox regression explored associations between developing anemia and rate of major adverse cardiovascular events (MACE), HF hospitalization, cancer, and death. During median 2.7 years, 34

Background Hypoglycemic pharmacotherapy interventions for alleviating the risk of dementia remain controversial, particularly regarding dipeptidyl peptidase 4 (DPP4) inhibitors vs metformin. Our objective was to investigate whether the initiation of DPP4 inhibitors, as opposed to metformin, was linked to a reduced risk of dementia.Methods We included individuals with type 2 diabetes over 40 years old who were new users of DPP4 inhibitors or metformin in the Chinese Renal Disease Data System database between 2009 and 2020. The study employed Kaplan-Meier and Cox regression for survival analysis and the Fine and Gray model for the competing risk of death.Results Following a 1:1 propensity score matching, the analysis included 3626 DPP4 inhibitor new users and an equal number of metformin new users. After adjusting for potential confounders, the utilization of DPP4 inhibitors was associated with a decreased risk of all-cause dementia compared to metformin [hazard ratio (HR) 0.63, 95% confidence interval (CI) 0.45-0.89]. Subgroup analysis revealed that the utilization of DPP4 inhibitors was associated with a reduced incidence of dementia in individuals who initiated drug therapy at the age of 60 years or older (HR 0.69, 95% CI 0.48-0.98), those without baseline macrovascular complications (HR 0.62, 95% CI 0.41-0.96), and those without baseline microvascular complications (HR 0.67, 95% CI 0.47-0.98).Conclusion In this real-world study, we found that DPP4 inhibitors presented an association with a lower risk of dementia in individuals with type 2 diabetes than metformin, particularly in older people and those without diabetes-related comorbidities.

CONTEXT:Thyroid dysfunction is prevalent in chronic kidney disease (CKD) patients and significantly impacts renal outcomes and mortality. OBJECTIVE:This study investigated the associations between thyroid function and clinical outcomes, and also the therapeutic effects of thyroid hormone replacement therapy (THRT) in CKD patients. METHODS:We conducted a retrospective cohort study using data from the China Renal Data System. The primary endpoints were composite renal failure and all-cause mortality. The secondary endpoint was the impact of THRT on renal outcomes. Associations were analyzed using multivariable Cox proportional hazards regression models and Kaplan-Meier survival analyses, with adjustment for relevant clinical and demographic covariates. RESULTS:Among 30 804 CKD patients enrolled, 26 673 (86.6%) had normal thyroid function, 2291 (7.4%) had hypothyroidism, and 1840 (6.0%) had hyperthyroidism. Hypothyroidism independently predicted increased risk of renal failure (adjusted HR = 1.29; 95% CI, 1.15-1.45; P < .001). Both hypothyroidism (adjusted HR = 1.24; 95% CI, 1.11-1.39; P < .001) and hyperthyroidism (adjusted HR = 1.20; 95% CI, 1.07-1.33; P < .01) were associated with increased all-cause mortality. Notably, THRT was associated with significantly reduced risk of renal failure (adjusted HR = 0.65; 95% CI, 0.52-0.82; P < .001) in hypothyroid patients. CONCLUSION:This large-scale cohort study demonstrates that hypothyroidism accelerates CKD progression, while both hypo- and hyperthyroidism increase mortality risk in CKD patients. THRT appears to attenuate the adverse effects of hypothyroidism on renal function. Regular thyroid function monitoring and appropriate THRT should be considered in CKD management.

Infection in patients with reduced kidney function is common and can be fatal. But, the association between reduced kidney function and the risk of acute infection in observational studies might not be causal. This study used both observational and Mendelian randomization (MR) analyses to examine the potential causal relationship between kidney function and acute infections. Kidney function assessed by creatinine based estimated glomerular filtration rate (eGFRcr) cystatin-based eGFR (eGFRcys) and blood urea nitrogen (BUN) of 435,563 white ancestry participants were derived from the UK Biobank. Association with Acute infection, defined as admission or death due to all acute infections, including specific types such as pneumonia, sepsis, urinary tract infection and skin or soft tissue infections were assessed with Cox proportional hazard models. Linear, nonlinear one-sample MR, and two-sample MR analyses were used to examine the associations between genetically predicted kidney function and acute infection. In the observational study, eGFRcr was nonlinearly associated with incident acute infection (Fig. 1). However, one-sample MR analysis provided neither linear nor nonlinear evidence for genetically predicted eGFRcr, with acute infection (hazard ratio [HR] 1.00, 95% CI 0.97–1.03) (Fig. 2), pneumonia (HR 1.01, 95% CI 0.96–1.06), sepsis (HR 0.99, 95% CI 0.93–1.06), skin soft tissue infection (HR 1.01, 95% CI 0.96–1.07), and urinary tract infection (HR 1.00, 95% C: 0.95–1.05). Similar results were obtained with eGFRcys or BUN as exposures in one-sample MR or in two-sample MR analyses. Our findings do not support a genetic link between kidney function and acute infections in the general population. Further study is warranted, especially across varying degrees of kidney function and diverse ethnic groups.

Higher dietary fiber intake (DFI) is linked to lower risk of frailty in older population. However, people with chronic kidney disease (CKD) often eat less fiber due to concerns about fiber and potassium-rich foods causing hyperkalemia. It remains unclear if the link between DFI and frailty applies to people with and without CKD. This cross-sectional study analysed data from the National Health and Nutrition Examination Survey (NHANES 2003–2018). DFI was calculated based on average of two days dietary recall. Frailty was evaluated by the 36-item frailty index. CKD was defined as estimated glomerular filtration rate < 60 mL/min/1.73 m2 and/or urinary albumin creatinine ratio ≥30 mg/g. The association of DFI with frailty were analysed using weighted multivariate logistic regression and restricted cubic splines (RCS). A total of 15304 adults (median age 63 years, 55% female) were included in this analysis. The prevalence of frailty was 30% in 4037 CKD patients and 9.5% in 11267 non-CKD population. Each SD (3.95 g/1000 kcal/day) increase of DFI was associated with 41% reduced odds of frailty in whole population {adjusted odds ratio (aOR) 0.59 [95% confidence interval (CI) 0.46–0.76]} and 44% in non-CKD population (aOR: 0.56, 95% CI: 0.41–0.77), but not in the CKD population (aOR: 0.67, 95% CI: 0.44–1.03). RCS analysis in whole population reveal linear association between DFI and frailty (P for nonlinearity =0.88, Fig. 1 ). The results of subgroup analysis in those with and without cardiovascular diseases (CVD), hypertension, drinking habit were consistent. DFI is associated with frailty in the non-CKD population but not in the CKD population. Other factors instead of DFI might contribute more on frailty in patients with CKD.

Frailty and sarcopenia are prevalent and could independently predict the adverse outcomes in patients maintaining dialysis. However, their coexistence profile and the interactive effect on mortality in non-dialysis dependent chronic kidney disease (ND-CKD) remains uncertain. This observational study analyzed data from the National Health and Nutrition Examination Survey. Frailty was evaluated by a validated 36-item frailty index, while sarcopenia was defined by appendicular skeletal muscle (ASM)/body mass index (BMI). Associations between frailty, sarcopenia, and their combination with mortality were examined using Cox proportional hazards models adjusted for potential covariates, presented as hazard ratios (HRs) and 95% confidence intervals (CI). Restricted cubic splines were applied to explore non-linear associations between the frailty index, sarcopenia score (defined as ASM/BMI) and mortality. Interaction effects between frailty and sarcopenia were assessed through interaction terms. Patients were followed from examination date at baseline until the occurrence of death or end of follow-up (December 31, 2019). A total of 1711 adult patients (median age 72 years, 42% men) with ND-CKD were included. The prevalence of frailty, sarcopenia and their co-occurrence was 37.6%, 29.6%, and 12.9%, respectively. Over a median follow-up of 10 years, 1,316 participants (76.9%) died. Frailty (HR: 1.51, 95% CI: 1.30–1.76), rather than sarcopenia (HR: 1.15, 95% CI: 0.96–1.37), was associated with an increased risk of all-cause mortality (Fig. 1). A linear relationship between the frailty index and all-cause mortality was observed (p for nonlinearity =0.86) (Fig. 2). There is no interaction effect between frailty and sarcopenia on mortality risk. Patients with both conditions did not show a significantly higher mortality risk compared to those with frailty alone (HR: 1.67 vs. 1.53, p for difference =0.6). Results were consistent in subgroup analyses, including age, sex and several comorbidities. There is no interaction effect between frailty and sarcopenia on mortality risk. Frailty, rather than sarcopenia, was associated with mortality in patients with ND-CKD. Future research should prioritize frailty screening in this population.

Early insulin therapy is capable to achieve glycemic control and restore β-cell function in newly diagnosed type 2 diabetes (T2D), but its effect on cardiovascular outcomes in these patients remains unclear. In this nationwide real-world study, we analyzed electronic health record data from 19 medical centers across China between 1 January 2000, and 26 May 2022. We included 5424 eligible patients (mean age 56 years, 2176 women/3248 men) who were diagnosed T2D within six months and did not have prior cardiovascular disease. Multivariable Cox regression models were used to estimate the associations of early insulin therapy (defined as the first-line therapy for at least two weeks in newly diagnosed T2D patients) with the incidence of major cardiovascular events including coronary heart disease (CHD), stroke, and hospitalization for heart failure (HF). During 17,158 persons years of observation, we documented 834 incident CHD cases, 719 stroke cases, and 230 hospitalized cases for HF. Newly diagnosed T2D patients who received early insulin therapy, compared with those who did not receive such treatment, had 31% lower risk of incident stroke, and 28% lower risk of hospitalization for HF. No significant difference in the risk of CHD was observed. We found similar results when repeating the aforesaid analysis in a propensity-score matched population of 4578 patients and with inverse probability of treatment weighting models. These findings suggest that early insulin therapy in newly diagnosed T2D may have cardiovascular benefits by reducing the risk of incident stroke and hospitalization for HF.

Rationale & Objective:Hypokalemia is common and potentially life-threatening in patients undergoing peritoneal dialysis (PD). However, the current literature has produced varying results. This study aimed to evaluate the prevalence and adverse outcomes of hypokalemia and the role of potassium supplementation in patients receiving PD. Study Design:Systematic review and meta-analysis of randomized controlled trials and observational studies. Setting & Study Populations:Adults receiving maintenance PD. Selection Criteria for Studies:Studies that investigated the prevalence and adverse outcomes of hypokalemia and the effect of potassium supplementation. Data Extraction:Two independent reviewers evaluated studies for eligibility and extracted relevant data. Analytical Approach:Random effects meta-analysis was conducted to pool hazard ratios (HRs) and 95% CIs for the outcomes of interest. The certainty of findings was rated according to the Grading of Recommendations Assessment, Development and Evaluation criteria. Results:Of 3,632 reports identified, 24 studies involving 60,313 participants met the inclusion criteria. The prevalence of hypokalemia was 37.9% (95% CI, 27.2%-52.7%), 17.7% (95% CI, 12.0%-25.9%), and 4.4% (95% CI, 1.9%-10.2%) in patients with potassium level <4.0, 3.5, and 3.0 mmol/L, respectively. Hypokalemia, according to the study's definition, was associated with increased risks of all-cause mortality (HR, 1.49; 95% CI, 1.18-1.89), cardiovascular mortality (HR, 1.50; 95% CI, 1.19-1.88), and PD-associated peritonitis (HR, 1.42; 95% CI, 1.17-1.73). These associations were consistent but with low to very low certainty. The effect of correcting hypokalemia with potassium supplementation in patients undergoing PD remains uncertain. Limitations:Heterogeneity persisted across most of the examined subgroups, and observational studies preclude causation. Conclusions:Hypokalemia is common and portends poorer survival and a higher risk of peritonitis among patients undergoing PD. Further research into the optimal prevention and treatment strategies for hypokalemia is warranted to improve outcomes. Registration:Registered at PROSPERO with registration number CRD42022358236.

Rationale & Objective: Individuals with a low estimated glomerular fi ltration rate (eGFR) are at a high risk of death. However, the causes underpinning this association are largely uncertain. This study aimed to assess the causal relationship of low eGFR with all-cause and cause- specific fi c mortality. Study Design: Retrospective cohort study incorporating Mendelian randomization (MR). Setting & Participants: Individual-level data from 436,214 White participants (54.3% female; aged 56.8 +/- 8.0 years) included in the UK Biobank. Exposures: eGFR estimated using cystatin C (eG FRcyst). cyst ). Outcomes: The outcomes of interest included all-cause mortality, cardiovascular mortality, cancer mortality, infection mortality, and other- cause mortality. Analytical Approach: Cox proportional hazards analysis for the conventional observational analyses; linear and nonlinear MR analyses implemented using genetic allele scores as instrumental variables representing kidney function to estimate the effect of kidney function on the survival outcomes. Results: During a median follow-up of 12.1 years, there were 30,489 deaths, 6,098 of which were attributed to cardiovascular events, 15,538 to cancer, 1,516 to infection, and 7,227 to other events. In the conventional observational analysis, eGFRcyst cyst exhibited a nonlinear association with all the outcomes. MR analysis suggested that a genetically predicted lower eGFRcyst cyst was linearly associated with a higher rate of cardiovascular mortality (HR, 1.43; 95% CI, 1.18-1.75) across the entire measurement range (every 10-mL/min/1.73 m2 2 decrement). Nonetheless, no causal associations between eGFRcyst cyst and all-cause mortality (HR, 1.07; 95% CI, 0.98-1.17) or any types of noncardiovascular mortality were detected. Limitations: Potential misclassification fi cation of the actual cause of death, a nonrepresentative sample, and potential error in the interpretation of the magnitude of associations generated in MR analyses. Conclusions: These fi ndings suggest a potential causal association between low eGFR and cardiovascular mortality in the general population, but no causal relationship with all-cause mortality or noncardiovascular mortality was observed. Further studies in other populations are warranted to confirm fi rm these fi ndings.

INTRODUCTION:Physical inactivity is prevalent and associated with adverse outcomes among patients with chronic kidney disease (CKD). Most previous studies have relied on subjective questionnaires to assess levels of physical activity (PA) and mainly focused on patients undergoing dialysis. Therefore, the Physical Activity Elements and Adverse Outcomes in Patients with Chronic Kidney Disease in Guangdong study aims to investigate the levels and types of PA elements and their association with adverse outcomes in Chinese non-dialysis CKD (ND-CKD) patients. METHODS AND ANALYSIS:In this prospective cohort study, 374 patients with ND-CKD will be recruited from Guangdong province, South of China. The primary exposure will be levels of PA assessed by ActiGraph GT3X+ accelerometer including the intensity, duration, frequency and type of PA. The traditional Chinese exercises such as tai chi and Baduanjin will also be assessed. The primary outcomes will be all-cause mortality. Other variables including demographics, comorbidities, medication and laboratory markers will be registered. All data will be updated annually for at least 5 years, or until the occurrence of death or initiation of renal replacement therapy. The Spearman correlation coefficient will be used to investigate the correlation between questionnaire-derived and accelerometry-derived PA. The Cox proportional hazards model will be used to investigate the association between level of PA and adverse outcomes. Non-linear associations between PA levels and outcomes, as well as the minimum desirable PA level, will be evaluated using restricted cubic splines. ETHICS AND DISSEMINATION:The ethical permission for this study was obtained from the ethics committee of Guangdong Provincial Hospital of Chinese Medicine in Guangzhou, China (B2015-152-02). Written informed consent is obtained from all participants. The results will be disseminated by publication in a peer-reviewed journal and presented at relevant conferences.

Background Inflammation is associated with adverse outcomes of chronic kidney disease (CKD) or chronic heart failure (CHF), but few large data exist. We aimed to explore the clinical associations, and prognostic consequences of inflammation-based scores in patients with CKD and CHF.Methods This work was a retrospective cohort study. Glasgow Prognostic Score (GPS), modified Glasgow Prognostic Score (mGPS), Prognostic Nutritional Index (PNI) and Prognostic Index (PI), were used to explore its relationship with CKD progression in patients with CKD stage 1-3b and CHF from the China Renal Data System (CRDS). The composite end point of this study was CKD progression which was defined as eGFR reduction of 40% or progression to end stage renal disease (ESRD).Results Of 8491 patients were enrolled. Kaplan-Meier curve showed that compared to the lower inflammation-based scores, the increased scores have a higher rate of CKD progression, whether in GPS, mGPS, PNI or PI (log-rank test, p < 0.001). After considering competing risk events, multivariable Cox hazards analysis revealed that GPS and PNI scores were significantly related to CKD progression [GPS: hazard ratio (HR) 1.40, 95% confidence interval (CI) 1.11-1.76, p = 0.005; PNI: HR 1.54, 95% CI 1.25-1.89, p < 0.001]. PNI showed acceptable prognostic value (C-index = 0.757, 95% CI 0.734-0.78) compared to GPS, mGPS and PI. In subgroup analysis, PNI was consistently related to CKD progression in patients with or without hypertension, DM, MI, VDH and CVD (P for interaction > 0.05).Conclusions Inflammation-based scores, especially PNI may be a useful clinical biomarker for CKD progression in CKD with CHF patients.

Background. General and abdominal obesity are prevalent, with established associations to frailty in the elderly. However, few studies have investigated these associations in patients with chronic kidney disease (CKD), yielding inconsistent results. Methods. This cross-sectional study analysed data from the National Health and Nutrition Examination Survey (NHANES 2003-2018). Frailty was evaluated by the 36-item frailty index. General obesity was defined as a body mass index (BMI) >30 kg/m(2); abdominal obesity was identified if waist circumference (WC) reached 102 cm in men and 88 cm in women. The associations of general and abdominal obesity with frailty were analysed using weighted multivariate logistic regression and restricted cubic splines. The interaction of general and abdominal obesity with frailty was examined. Results. A total of 5604 adult patients (median age 71 years, 42% men) with CKD were included in this analysis, with a median estimated glomerular filtration rate of 57.3 ml/min/1.73 m2. A total of 21% were frail with general obesity and 32% were frail with abdominal obesity. Neither general nor abdominal obesity alone was associated with frailty. There was an interaction between general and abdominal obesity with frailty. Compared with individuals with normal BMI and WC, those with both general and abdominal obesity, rather than either alone, exhibited significantly increased odds of frailty {odds ratio [OR] 1.53 [95% confidence interval (CI) 1.20-1.95]}. General obesity was associated with being frail only when CKD patients had abdominal obesity [OR 1.59 (95% CI 1.08-2.36)]. Conclusions. There may be an interaction between general and abdominal obesity with frailty in patients with CKD. Interventions aimed at preventing frailty should consider both aspects.

>Dear Editor,Heart failure (HF) is a common multi-faceted and lifethreatening syndrome,of which up to 23%occur acute kidney injury (AKI)[1].HF-related AKI is largely overlooked or delayed in identification[2].Approximately 85%of AKI cases that occurred during cardiac hospitalization in China were either ignored or identified too late [3].Currently,there are no specific guidelines for the management of HF-related AKI.Hence,it is essential to identify patients at the risk of developing AKI and intervene promptly,to reduce social and economic burden.

Background. Postoperative acute kidney injury (AKI) is a common condition after surgery, however, the available data about nationwide epidemiology of postoperative AKI in China from large and high-quality studies are limited. This study aimed to determine the incidence, risk factors and outcomes of postoperative AKI among patients undergoing surgery in China. Methods. This was a large, multicentre, retrospective study performed in 16 tertiary medical centres in China. Adult patients (>= 18 years of age) who underwent surgical procedures from 1 January 2013 to 31 December 2019 were included. Postoperative AKI was defined by the Kidney Disease: Improving Global Outcomes creatinine criteria. The associations of AKI and in-hospital outcomes were investigated using logistic regression models adjusted for potential confounders. Results. Among 520 707 patients included in our study, 25 830 (5.0%) patients developed postoperative AKI. The incidence of postoperative AKI varied by surgery type, which was highest in cardiac (34.6%), urologic (8.7%) and general (4.2%) surgeries. A total of 89.2% of postoperative AKI cases were detected in the first 2 postoperative days. However, only 584 (2.3%) patients with postoperative AKI were diagnosed with AKI on discharge. Risk factors for postoperative AKI included older age, male sex, lower baseline kidney function, pre-surgery hospital stay <= 3 days or >7 days, hypertension, diabetes mellitus and use of proton pump inhibitors or diuretics. The risk of in-hospital death increased with the stage of AKI. In addition, patients with postoperative AKI had longer lengths of hospital stay (12 versus 19 days) and were more likely to require intensive care unit care (13.1% versus 45.0%) and renal replacement therapy (0.4% versus 7.7%). Conclusions. Postoperative AKI was common across surgery type in China, particularly for patients undergoing cardiac surgery. Implementation and evaluation of an alarm system is important for the battle against postoperative AKI.