Glomerular hyperfiltration: definitions, mechanisms and clinical implications

Glomerular Hyperfiltration and Cancer: A Nationwide Population-Based Study

BACKGROUND

Glomerular hyperfiltration is associated with all-cause mortality. Herein, we evaluated the association between glomerular hyperfiltration and the development of cancer, the most common cause of death, in an Asian population.

METHODS

We retrospectively reviewed the National Health Insurance Service database of Korea for people who received national health screenings from 2012 to 2013. Glomerular hyperfiltration was defined as the 95th percentile and greater after stratification by sex and age decile. We performed a multivariate Cox regression analysis using glomerular hyperfiltration at the first health screening as the exposure variable and cancer development as the outcome variable to evaluate the impact of glomerular hyperfiltration on the development of cancer.

RESULTS

A total of 1,953,123 examinations for patients with a median follow-up time of 4.4 years were included in this study. Among the 8 different site-specific cancer categories, digestive organs showed significant associations between glomerular hyperfiltration and cancer. The population with glomerular hyperfiltration showed an increased risk for stomach cancer [adjusted hazard ratio (aHR) = 1.22], colorectal cancer (aHR = 1.16), and liver or intrahepatic malignancy (aHR = 1.35).

CONCLUSIONS

Glomerular hyperfiltration was associated with an increased risk for the development of cancer in specific organs, such as the stomach, colorectum, and liver and intrahepatic organ.

IMPACT

Glomerular hyperfiltration needs to be considered a significant sign of the need to evaluate the possibility of hidden adverse health conditions, including malignancies.

Novel renal biomarkers show that creatine supplementation is safe: a double-blind, placebo-controlled randomized clinical trial

The aim of this study was to evaluate the impact of creatine supplementation (CS) on renal function in young, healthy, and active subjects. We used a randomized, double-blind, placebo-controlled clinical trial as the study design. Thirty-six healthy male university students were recruited and divided into three groups: group placebo, group G3 (3 g/day of CS), and group G5 (5 g/day of CS). To assess renal function, new kidney biomarkers, kidney injury molecule-1 (KIM-1) and monocyte chemoattractant protein-1 (MCP-1), were quantified. Serum albumin, serum creatinine, serum urea, estimated glomerular filtration rate (eGFR), proteinuria, and albuminuria were also measured. All groups were evaluated at two times: prior CS or placebo (pre) and after 35 days on CS or placebo (post). After 35 days of intervention, all characteristics were maintained without significant difference (P > 0.05) between the groups, including serum creatinine, eGFR, and more sensitive kidney biomarker concentrations (KIM-1 and MCP-1). The paired analysis showed that the supplemented groups (G3 and 5G) had increased serum creatinine and decreased eGFR levels (P < 0.05). However, the values were still within the normal reference range. In conclusion, the results of renal function evaluation did not show any difference between the evaluated groups. Increased serum creatinine and decreased eGFR levels in CS groups can be explained by increased creatine stores and metabolism, since creatinine is a by-product of creatine metabolism. These findings indicate that the use of CS at doses of 3 g and 5 g/day for a short period (35 days) is safe and did not impair the kidneys or renal function in young healthy subjects.

Programming of Renal Development and Chronic Disease in Adult Life

Chronic kidney disease (CKD) can have an insidious onset because there is a gradual decline in nephron number throughout life. There may be no overt symptoms of renal dysfunction until about two thirds or more of the nephrons have been destroyed and glomerular filtration rate (GFR) falls to below 25% of normal (often in mid-late life) (Martinez-Maldonaldo et al., 1992). Once End Stage Renal Disease (ESRD) has been reached, survival depends on renal replacement therapy (RRT). CKD causes hypertension and cardiovascular disease; and hypertension causes CKD. Albuminuria is also a risk factor for cardiovascular disease. The age of onset of CKD is partly determined during fetal life. This review describes the mechanisms underlying the development of CKD in adult life that results from abnormal renal development caused by an adverse intrauterine environment. The basis of this form of CKD is thought to be mainly due to a reduction in the number of nephrons formed in utero which impacts on the age dependent decline in glomerular function. Factors that affect the risk of reduced nephron formation during intrauterine life are discussed and include maternal nutrition (malnutrition and obesity, micronutrients), smoking and alcohol, use of drugs that block the maternal renin-angiotensin system, glucocorticoid excess and maternal renal dysfunction and prematurity. Since CKD, hypertension and cardiovascular disease add to the disease burden in the community we recommend that kidney size at birth should be recorded using ultrasound and those individuals who are born premature or who have small kidneys at this time should be monitored regularly by determining GFR and albumin:creatinine clearance ratio. Furthermore, public health measures aimed at limiting the prevalence of obesity and diabetes mellitus as well as providing advice on limiting the amount of protein ingested during a single meal, because they are all associated with increased glomerular hyperfiltration and subsequent glomerulosclerosis would be beneficial.

A high triglyceride glucose index is more closely associated with hypertension than lipid or glycemic parameters in elderly individuals: a cross-sectional survey from the Reaction Study

Background

Both lipid and glucose abnormalities are associated with hypertension (HTN). However, it is unclear whether the triglyceride-glucose (TyG) index is associated with HTN. Therefore the aim of this study is to investigate the association of the TyG index and HTN and to compare the discriminative power of the TyG index, lipid, glycemic parameters for the risk of HTN in elderly individuals.

Methods

The present study was nested in a longitudinal (REACTION) study from May 2011 to December 2011, which was designed to demonstrate the association of abnormal glucose metabolism with the risk of cancer in the Chinese population. In total, 47,808 participants were recruited in this cross-sectional study. The TyG index was divided into five groups: the < 20% group, the 20–39% group, the 40–59% group, the 60–79% group and the ≥ 80% group, according to quintile division of the subjects. Three multivariate logistic regression models were used to evaluate the association between the TyG vs. lipid parameters, glycemic parameters and HTN.

Results

Multivariate logistic regression analysis shows that compared with lipid and glycemic parameters, the TyG index remains significantly associated with HTN in either total subjects or subjects separated into men and women (odds ratio (OR) 1.33, 95% confidence interval (CI) 1.18–1.51, p < 0.0001 in total subjects; OR 1.39, 95% CI 1.11–1.74, p = 0.0042 in men; OR 1.28, 95% CI 1.11–1.49, p = 0.0010 in women). In a stratified analysis, an elevated TyG index is significantly associated with HTN in the subgroup of the oldest age (≥ 65) (OR 1.67, 95% CI 1.30–2.14, p < 0.0001), as well as with obesity (Body mass index (BMI) ≥ 28 kg/m²) (OR 1.85, 95% CI 1.29–2.66, p = 0.0009) or lower estimated glomerular filtration rate (eGFR) (< 90 mL/(min·1.73 m²)) (OR 1.72, 95% CI 1.33–2.21, p < 0.0001).

Conclusion

The TyG index is significantly associated with HTN and shows the superior discriminative ability for HTN compared with lipid and glycemic parameters in the Chinese elderly population.

Renal hyperfiltration is independently associated with increased all-cause mortality in individuals with type 2 diabetes: a prospective cohort study

INTRODUCTION

In addition to favoring renal disease progression, renal 'hyperfiltration' has been associated with an increased risk of death, though it is unclear whether and how excess mortality is related to increased renal function. We investigated whether renal hyperfiltration is an independent predictor of death in patients with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events Italian multicenter study.

RESEARCH DESIGN AND METHODS

This observational, prospective cohort study enrolled 15 773 patients with type 2 diabetes consecutively attending 19 Italian diabetes clinics in 2006-2008. Serum creatinine, albuminuria, cardiovascular risk factors, and complications/comorbidities were assessed at baseline. Vital status on 31 October 2015 was retrieved for 15 656 patients (99.26%). Patients were stratified (A) by absolute estimated glomerular filtration rate (eGFR) values in eGFR deciles or Kidney Disease: Improving Global Outcomes (KDIGO) categories and (B) based on age-corrected thresholds or age and gender-specific 95th and 5th percentiles in hyperfiltration, hypofiltration, and normofiltration groups.

RESULTS

The highest eGFR decile/category and the hyperfiltration group included (partly) different individuals with similar clinical features. Age and gender-adjusted death rates were significantly higher in deciles 1, 9, and 10 (≥103.9, 50.9-62.7, and <50.9 mL/min/1.73 m², respectively) versus the reference decile 3 (92.9-97.5 mL/min/1.73 m²). Mortality risk, adjusted for multiple confounders, was also increased in deciles 1 (HR 1.461 (95% CI 1.175 to 1.818), p=0.001), 9 (1.312 (95% CI 1.107 to 1.555), p=0.002), and 10 (1.976 (95% CI 1.673 to 2.333), p<0.0001) versus decile 3. Similar results were obtained by stratifying patients by KDIGO categories. Death rates and adjusted mortality risks were significantly higher in hyperfiltering and particularly hypofiltering versus normofiltering individuals.

CONCLUSIONS

In type 2 diabetes, both high-normal eGFR and hyperfiltration are associated with an increased risk of death from any cause, independent of confounders that may directly impact on mortality and/or affect GFR estimation. Further studies are required to clarify the nature of this relationship.

TRIAL REGISTRATION NUMBER

NCT00715481.

Stereotactic Ablative Radiotherapy for ≥T1b Primary Renal Cell Carcinoma: A Report From the International Radiosurgery Oncology Consortium for Kidney (IROCK)

PURPOSE

Patients with larger (T1b, >4 cm) renal cell carcinoma (RCC) not suitable for surgery have few treatment options because thermal ablation is less effective in this setting. We hypothesize that SABR represents an effective, safe, and nephron-sparing alternative for large RCC.

METHODS AND MATERIALS

Individual patient data from 9 institutions in Germany, Australia, USA, Canada, and Japan were pooled. Patients with T1a tumors, M1 disease, and/or upper tract urothelial carcinoma were excluded. Demographics, treatment, oncologic, and renal function outcomes were assessed using descriptive statistics. Kaplan-Meier estimates and univariable and multivariable Cox proportional hazards regression were generated for oncologic outcomes.

RESULTS

Ninety-five patients were included. Median follow-up was 2.7 years. Median age was 76 years, median tumor diameter was 4.9 cm, and 81.1% had Eastern Cooperative Oncology Group performance status of 0 to 1 (or Karnofsky performance status ≥70%). In patients for whom operability details were reported, 77.6% were defined as inoperable as determined by the referring urologist. Mean baseline estimated glomerular filtration rate (eGFR) was 57.2 mL/min (mild-to-moderate dysfunction), with 30% of the cohort having moderate-to-severe dysfunction (eGFR <45mL/min). After SABR, eGFR decreased by 7.9 mL/min. Three patients (3.2%) required dialysis. Thirty-eight patients (40%) had a grade 1 to 2 toxicity. No grade 3 to 5 toxicities were reported. Cancer-specific survival, overall survival, and progression-free survival were 96.1%, 83.7%, and 81.0% at 2 years and 91.4%, 69.2%, 64.9% at 4 years, respectively. Local, distant, and any failure at 4 years were 2.9%, 11.1%, and 12.1% (cumulative incidence function with death as competing event). On multivariable analysis, increasing tumor size was associated with inferior cancer-specific survival (hazard ratio per 1 cm increase: 1.30; P < .001).

CONCLUSIONS

SABR for larger RCC in this older, largely medically inoperable cohort, demonstrated efficacy and tolerability and had modest impact on renal function. SABR appears to be a viable treatment option in this patient population.

Estimation of Intraglomerular Pressure Using Invasive Renal Arterial Pressure and Flow Velocity Measurements in Humans

BACKGROUND

Glomerular hyperfiltration resulting from an elevated intraglomerular pressure (Pglom) is an important cause of CKD, but there is no feasible method to directly assess Pglom in humans. We developed a model to estimate Pglom in patients from combined renal arterial pressure and flow measurements.

METHODS

We performed hemodynamic measurements in 34 patients undergoing renal or cardiac angiography under baseline conditions and during hyperemia induced by intrarenal dopamine infusion (30 μg/kg). For each participant during baseline and hyperemia, we fitted an adapted three-element Windkessel model that consisted of characteristic impedance, compliance, afferent resistance, and Pglom.

RESULTS

We successfully analyzed data from 28 (82%) patients. Median age was 58 years (IQR, 52-65), median eGFR was 95 ml/min per 1.73 m² (IQR, 74-100) using the CKD-EPI formula, 30% had microalbuminuria, and 32% had diabetes. The model showed a mean Pglom of 48.0 mm Hg (SD=10.1) at baseline. Under hyperemia, flow increased by 88% (95% CI, 68% to 111%). This resulted in a 165% (95% CI, 79% to 294%) increase in afferent compliance and a 13.1-mm Hg (95% CI, 10.0 to 16.3) decrease in Pglom. In multiple linear regression analysis, diabetes (coefficient, 10.1; 95% CI, 5.1 to 15.1), BMI (0.99 per kg/m²; 95% CI, 0.38 to 1.59), and renal perfusion pressure (0.42 per mm Hg; 95% CI, 0.25 to 0.59) were significantly positively associated with baseline Pglom.

CONCLUSIONS

We constructed a model on the basis of proximal renal arterial pressure and flow velocity measurements that provides an overall estimate of glomerular pressure and afferent and efferent resistance in humans. The model provides a novel research technique to evaluate the hemodynamics of CKD on the basis of direct pressure and flow measurements.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Functional HEmodynamics in patients with and without Renal Artery stenosis (HERA), NL40795.018.12 at the Dutch national trial registry (toetsingonline.nl).

Obesity-Related Glomerulopathy: A Latent Change in Obesity Requiring More Attention

BACKGROUND

Obesity has become a major public health problem, and the prevalence of kidney diseases has increased in parallel. Among kidney diseases caused by metabolic disorders, obesity-related glomerulopathy (ORG) is secondary to obesity.

SUMMARY

ORG is mainly caused by glomerular hyperfiltration, dysregulation of hormone and cytokine secretion in adipose tissues, and ectopic lipid accumulation in renal cells. ORG is pathologically characterized by glomerular hypertrophy, with or without focal and segmental glomerulosclerosis. Patients with ORG usually present with proteinuria concomitant with metabolic disorders such as dyslipidemia and hypertension. Weight loss, RAAS inhibitors, and improved insulin resistance can reduce the progression of ORG.

CONCLUSION

ORG is a growing renal pathological change in obese individuals, and a comprehensive understanding of the disease is pivotal to avoid its occurrence and improve quality of life for those with obesity. Key Messages:This review comprehensively describes the characteristics of ORG in pathological changes, clinical manifestations, pathogeneses and treatments.

Association between Depression and Renal Hyperfiltration in a General Chinese Population

BACKGROUND

Depression is prevalent in patients with all stages of CKD and is associated with adverse outcome. Abnormally elevated GFR, or hyperfiltration, may play a crucial role in the initiation and progression of CKD. However, the association between depression and hyperfiltration is not known. The aim of this study is to investigate the relationship between depression and hyperfiltration.

METHODS

This was an observational cross-sectional study. A total of 3,716 volunteers (1,303 males and 2,413 females) aged 40-75 years without CKD from a community in China were included for the study. Depressive symptoms and the presence of a minor or major depressive episode were assessed with the 9-item Patient Health Questionnaire (PHQ-9) and Diagnostic and Statistical Manual of Mental Disorders (4th edition)-based structured interview, respectively.

RESULTS

The mean age of the participants in the present study was 53.8 ± 9.0 years. 115 participants had clinically relevant depression, and 122 participants had a minor or major depressive episode. In a multivariable logistic regression analysis adjusted for potential confounders, the association between clinically relevant depression and renal hyperfiltration remained significant in men but not in women. As compared with men without depression (PHQ <5) or depressive episodes, those with clinically relevant depression (PHQ ≥10) had a significantly higher risk of renal hyperfiltration. The fully adjusted OR (95% CI) was 4.81 (1.62-14.30, p = 0.005), those with a major depressive episode had a higher risk of renal hyperfiltration (OR 7.45; 95% CI 2.04-27.21, p = 0.002).

CONCLUSION

Depressive symptoms and major depressive episodes are associated with renal hyperfiltration in middle-aged and elderly Chinese men without CKD. Future studies are needed to verify and clarify the role of depression in the development of abnormally high eGFR and CKD.

Kidney and vascular function in adult patients with hereditary fructose intolerance

Objective: Previous studies have shown that patients with hereditary fructose intolerance (HFI) are characterized by a greater intrahepatic triglyceride content, despite a fructose-restricted diet. The present study aimed to examine the long-term consequences of HFI on other aldolase-B-expressing organs, i.e. the kidney and vascular endothelium.

Methods: Fifteen adult HFI patients were compared to healthy control individuals matched for age, sex and body mass index. Aortic stiffness was assessed by carotid-femoral pulse wave velocity (cf-PWV) and endothelial function by peripheral arterial tonometry, skin laser doppler flowmetry and the endothelial function biomarkers soluble E-selectin [sE-selectin] and von Willebrand factor. Serum creatinine and cystatin C were measured to estimate the glomerular filtration rate (eGFR). Urinary glucose and amino acid excretion and the ratio of tubular maximum reabsorption of phosphate to GFR (TmP/GFR) were determined as measures of proximal tubular function. Results: Median systolic blood pressure was significantly higher in HFI patients (127 versus 122 mmHg, p = .045). Pulse pressure and cf-PWV did not differ between the groups (p = .37 and p = .49, respectively). Of all endothelial function markers, only sE-selectin was significantly higher in HFI patients (p = .004). eGFR was significantly higher in HFI patients than healthy controls (119 versus 104 ml/min/1.73m², p = .001, respectively). All measurements of proximal tubular function did not differ significantly between the groups.

Conclusions: Adult HFI patients treated with a fructose-restricted diet are characterized by a higher sE-selectin level and slightly higher systolic blood pressure, which in time could contribute to a greater cardiovascular risk. The exact cause and, hence, clinical consequences of the higher eGFR in HFI patients, deserves further study.

Estimated Glomerular Filtration Rate as a Risk Stratification Tool for Early Complications in Revision Total Hip and Knee Arthroplasty

BACKGROUND

Establishing an association between postoperative outcomes and the spectrum of renal function would allow for more informed decisions to manage surgical risks and improved patient-specific care. Estimated glomerular filtration rate (eGFR) can be calculated from standard prescreening measurements to gauge renal function. This work investigates the effect of eGFR, as a continuous and categorical variable, on mortality and major and minor complications in patients undergoing revision total knee and hip arthroplasty.

METHODS

25,056 patients having undergone revision total hip and knee arthroplasty from 2013 to 2016 were identified using the National Quality Improvement Program database. The investigated outcomes included 30-day mortality, major complications, and minor complications. Multivariate regression models were created to evaluate the effect of eGFR on the outcomes of interest. Multivariate spline regressions were generated to assess for nonlinear relationships between eGFR as a continuous variable and the outcomes.

RESULTS

Our study revealed that as eGFR decreased <60 mL/min/1.73 m², mortality (P = .0001), any major complication (P < .001), and any minor complication (P < .001) increased. Patients with eGFR 15-30 mL/min/1.73 m² had increased risk for mortality (P = .033). There was an increased risk for any major complication at an eGFR 30-60 and <15 mL/min/1.73 m², (P < .05). There was an increased risk of minor complications for those with hyperfiltration and <60 mL/min/1.73 m².

CONCLUSION

Patients with lower preoperative eGFR generally display an increased risk for complications after revision total hip and knee arthroplasty. Proper consideration should be given to this patient population before surgical intervention to allow for preventative measures to be taken to improve patient outcomes.

Renal tubular damage and worsening renal function in chronic heart failure: Clinical determinants and relation to prognosis (Bio-SHiFT study)

Background

It is uncertain that chronic heart failure (CHF) patients are susceptible to renal tubular damage with that of worsening renal function (WRF) preceding clinical outcomes.

Hypothesis

Changes in tubular damage biomarkers are stronger predictors of subsequent clinical events than changes in creatinine (Cr), and both have different clinical determinants.

Methods

During 2.2 years, we repeatedly simultaneously collected a median of 9 blood and 8 urine samples per patient in 263 CHF patients. We determined the slopes (rates of change) of the biomarker trajectories for plasma (Cr) and urinary tubular damage biomarkers N‐acetyl‐β‐d‐glucosaminidase (NAG), and kidney‐injury‐molecule (KIM)‐1. The degree of tubular injury was ranked according to NAG and KIM‐1 slopes: increase in neither, increase in either, or increase in both; WRF was defined as increasing Cr slope. The composite endpoint comprised HF‐hospitalization, cardiac death, left ventricular assist device placement, and heart transplantation.

Results

Higher baseline NT‐proBNP and lower eGFR predicted more severe tubular damage (adjusted odds ratio, adj. OR [95%CI, 95% confidence interval] per doubling NT‐proBNP: 1.26 [1.07‐1.49]; per 10 mL/min/1.73 m² eGFR decrease 1.16 [1.03‐1.31]). Higher loop diuretic doses, lower aldosterone antagonist doses, and higher eGFR predicted WRF (furosemide per 40 mg increase: 1.32 [1.08‐1.62]; spironolactone per 25 mg decrease: 1.76 [1.07‐2.89]; per 10 mL/min/1.73 m² eGFR increase: 1.40 [1.20‐1.63]). WRF and higher rank of tubular injury individually entailed higher risk of the composite endpoint (adjusted hazard ratios, adj. HR [95%CI]: WRF 1.9 [1.1‐3.4], tubular 8.4 [2.6‐27.9]; when combined risk was highest 15.0 [2.0‐111.0]).

Conclusion

Slopes of tubular damage and WRF biomarkers had different clinical determinants. Both predicted clinical outcome, but this association was stronger for tubular injury. Prognostic effects of both appeared independent and additive.

Association of Glomerular Hyperfiltration and Cardiovascular Risk in Middle-Aged Healthy Individuals

IMPORTANCE

Glomerular hyperfiltration is associated with increased risk of cardiovascular disease in high-risk conditions, but its significance in low-risk individuals is uncertain.

OBJECTIVE

To determine whether glomerular hyperfiltration is associated with increased cardiovascular risk in healthy individuals.

DESIGN, SETTING, AND PARTICIPANTS

This was a prospective population-based cohort study, for which enrollment took place from August 2009 to October 2010, with follow-up available through March 31, 2016. Analysis of the data took place in October 2019. The cohort was composed of 9515 healthy individuals, defined as individuals without hypertension, diabetes, cardiovascular disease, estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2, or statin and/or aspirin use, identified among 20 004 patients aged 40 to 69 years with health information accessed through the CARTaGENE research platform.

EXPOSURES

Individuals with glomerular hyperfiltration (eGFR >95th percentile after stratification for sex and age) were compared with individuals with normal filtration rate (eGFR 25th-75th percentiles).

MAIN OUTCOMES AND MEASURES

Adverse cardiovascular events were defined as a composite of cardiovascular mortality, myocardial infarction, unstable angina, heart failure, stroke, and transient ischemic attack. Risk of adverse cardiovascular events was assessed using Cox and fractional polynomial regressions and propensity score matching.

RESULTS

From the 20 004 CARTaGENE participants, 9515 healthy participants (4050 [42.6%] male; median [interquartile range] age, 50.4 [45.9-55.6] years) were identified. Among these, 473 had glomerular hyperfiltration (median [interquartile range] eGFR, 112 [107-115] mL/min/1.73 m2) and 4761 had a normal filtration rate (median [interquartile range] eGFR, 92 [87-97] mL/min/1.73 m2). Compared with the normal filtration rate, glomerular hyperfiltration was associated with an increased cardiovascular risk (hazard ratio, 1.88; 95% CI, 1.30-2.74; P = .001). Findings were similar with propensity score matching. The fractional polynomial regression showed that only the highest eGFR percentiles were associated with increased cardiovascular risk. The cardiovascular risk of individuals with glomerular hyperfiltration was similar to that of the 597 participants with an eGFR between 45 and 60 mL/min/1.73 m2 (hazard ratio, 0.90; 95% CI, 0.56-1.42; P = .64).

CONCLUSIONS AND RELEVANCE

These findings suggest that glomerular hyperfiltration is independently associated with increased cardiovascular risk in middle-aged healthy individuals. This risk profile appears to be similar to stage 3a chronic kidney disease.

Implications of early diagnosis of autosomal dominant polycystic kidney disease: A post hoc analysis of the TEMPO 3:4 trial

It is unknown whether early diagnosis of autosomal dominant polycystic kidney disease (ADPKD) can enable earlier management and improve outcomes. We conducted a post hoc analysis of data from the TEMPO 3:4 trial. Subjects were stratified by ADPKD diagnosis at age ≤18 (childhood diagnosis [CD]) or>18 (adulthood diagnosis [AD]). Groups were compared for baseline characteristics and total kidney volume (TKV) growth and estimated glomerular filtration rate (eGFR) decline over 3 years. 294 CD and 1148 AD subjects were analyzed. At inclusion, CD subjects were younger (mean age 34.2 versus 39.8 years; p < 0.0001) and had better eGFR (mean ± SD 87.4 ± 23.9 versus 80.1 ± 20.7 mL/min/1.73 m²; p < 0.0001), while CD had more severe Mayo risk classification (p < 0.0001) and more PKD1 mutations (p = 0.003). No statistical differences were found in TKV or eGFR change. At study end, placebo-treated CD subjects had better eGFR than projected by a prediction equation (mean difference ±SD for observed versus predicted eGFR: 2.18 ± 10.7 mL/min/1.73 m²; p = 0.0475). However, these results are not confirmed when excluding stage 1 CKD. Whether CD subjects, despite their risk profile, have a slower disease course than predicted remains inconclusive. Future studies are needed to confirm that early diagnosis and management can alter the disease course of ADPKD.

Sodium-glucose cotransporter 2 (SGLT-2) inhibitors and microvascular outcomes in patients with type 2 diabetes: systematic review and meta-analysis

PURPOSE

The effect of the sodium-glucose 2 (SGLT-2) inhibitors on microvascular complications remains uncertain. We performed a systematic review to determine the efficacy of the SGLT-2 inhibitors on microvascular outcomes in patients with type 2 diabetes.

METHODS

A comprehensive search was performed using Ovid, MEDLINE, EMBASE, Web of Science, and Scopus from inception to May 2019. Randomized trials comparing SGLT-2 inhibitors with placebo or other medication for type 2 diabetes for ≥ 4 weeks were included. Diabetes-related microvascular complications such as nephropathy, retinopathy, neuropathy, and peripheral vascular disease were evaluated. A random-effect model using mean differences for continuous outcomes and risk ratio for dichotomous outcomes was used to synthesize data. PROSPERO (CRD 42017076460).

RESULTS

A total of 40 RCTs with overall moderate quality of evidence were included. SGLT-2 inhibitors reduced the risk of renal-replacement therapy (0.65; 95% CI 0.54-0.79), renal death (0.57; 95% CI 0.49-0.65), and progression of albuminuria (0.69; 95% CI 0.66-0.73). Conversely, they appeared ineffective in maintaining eGFR (0.33; 95% CI - 0.74 to 1.41) or reducing serum creatinine (- 0.07; 95% CI - 0.26 to 0.11), whereas urine albumin-creatinine ratio (- 23.4; 95% CI - 44.6 to - 2.2) was reduced. Risk of amputation was non-significant (1.30; 95% CI 0.93-1.83). No available data were found regarding neuropathy and retinopathy to perform a quantitative analysis.

CONCLUSION

SGLT-2 inhibitors may reduce the risk of renal patient-important outcomes but fail to improve surrogate outcomes. Apparently, no increased risk of amputations was observed with these medications. No data were available regarding other microvascular complications.

Altered renal hemodynamics is associated with glomerular lipid accumulation in obese Dahl salt-sensitive leptin receptor mutant rats

The present study examined whether development of renal injury in the nondiabetic obese Dahl salt-sensitive leptin receptor mutant (SS^LepRmutant) strain is associated with elevations in glomerular filtration rate and renal lipid accumulation. Baseline mean arterial pressure at 6 wk of age was similar between Dahl salt-sensitive wild-type (SS_WT) and SS^LepRmutant rats. However, by 18 wk of age, the SS^LepRmutant strain developed hypertension, while the elevation in mean arterial pressure was not as severe in SS_WT rats (192 ± 4 and 149 ± 6 mmHg, respectively). At baseline, proteinuria was fourfold higher in SS^LepRmutant than SS_WT rats and remained elevated throughout the study. The early development of progressive proteinuria was associated with renal hyperfiltration followed by a decline in renal function over the course of study in the SS^LepRmutant compared with SS_WT rats. Kidneys from the SS^LepRmutant strain displayed more glomerulosclerosis and glomerular lipid accumulation than SS_WT rats. Glomeruli were isolated from the renal cortex of both strains at 6 and 18 wk of age, and RNA sequencing was performed to identify genes and pathways driving glomerular injury. We observed significant increases in expression of the influx lipid transporters, chemokine (C-X-C motif) ligand 16 (Cxcl16) and scavenger receptor and fatty acid translocase (Cd36), respectively, and a significant decrease in expression of the efflux lipid transporter, ATP-binding cassette subfamily A member 2 (Abca2; cholesterol efflux regulatory protein 2), in SS^LepRmutant compared with SS_WT rats at 6 and 18 wk of age, which were validated by RT-PCR analysis. These data suggest an association between glomerular hyperfiltration and glomerular lipid accumulation during the early development of proteinuria associated with obesity.

Prognostic value of connective tissue growth factor and c-Myb expression in IgA nephropathy and Henoch-Schönlein purpura-A pilot immunohistochemical study

AIM

Adverse and advanced prognostic signs in IgA nephropathy (IgAN) are interstitial fibrosis and tubular atrophy, but early predictors of bad outcome are still lacking. We investigated expression of connective tissue growth factor (CTGF) and c-Myb in renal biopsies of IgAN and Henoch-Schönlein purpura (HSP), because these gene products are indirectly included in fibrosis and epithelial-mesenchymal transition (EMT).

METHODS

The sample included 23 patients and 8 controls who underwent nephrectomy due to renal cancer. The slides cut from the paraffin blocks were prepared for standard indirect immunoflourescence, using antibodies to CTGF and c-Myb. Ten high-power non-overlapping fields were photographed on Olympus IX51 microscope. Average percent of positive tubular cells, as well as number of positive cells per glomerulus were calculated.

RESULTS

The cytoplasmic tubular CTGF expression was higher in IgAN/HSP than in controls (P < 0.001), whereas no difference was found in glomeruli (P = 0.437). The nuclear c-Myb expresssion in glomeruli and tubules was higher in IgAN/HSP than in controls (P < 0.05). In the follow-up, decline in renal function correlated with glomerular and tubular c-Myb, as well as tubular CTGF expression (all P < 0.05).

CONCLUSION

Our results proposed c-Myb and CTGF as novel, early and sensitive markers of chronic kidney disease and worse renal outcome, but larger series are needed.

Kidney function in minority children and adolescents with metabolically healthy and unhealthy obesity

Metabolic syndrome and/or body mass index (BMI) ≥40 kg/m² are risk factors for kidney function decline in the general population. To compare creatinine (Cr), estimated glomerular filtration rate (eGFR) and blood urea nitrogen (BUN) between minority children and adolescents with metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO), a chart review was conducted on subjects aged 4 to 20 years with BMI ≥95^th percentile from July 2014 to April 2017. They were stratified into MHO and MUO groups. Cr, eGFR and BUN were studied. Total n = 277: MHO n = 105 vs MUO n = 172. Cr was higher and BUN was lower in MUO whereas eGFR did not differ between the groups. Using general linear model, we found that metabolic status predicted BUN (P = .009) but not Cr or eGFR. When age, sex and Tanner stage matched, BUN, Cr and eGFR were similar between the groups. Higher BUN in MHO could be due to higher dietary protein intake. Subjects were divided into BMI ≥40 vs <40 kg/m² , BUN and eGFR were not different. A trend towards higher Cr in those with BMI ≥40 kg/m² (P = .054) was found; the group being older and taller. After age and height matching, all outcomes were not different. Higher Cr was found in those with elevated blood pressures vs the MHO (P = .047). Those with diastolic blood pressure (DBP) ≥90^th percentile had higher Cr than those with systolic blood pressure ≥90^th percentile (P = .017). Children and adolescents with MUO, and those with BMI ≥40 kg/m² did not appear to have early diminished kidney function. Higher Cr, although in normal range, occurred in those with abnormal DBP.

Glomerular hyperfiltration is associated with dementia: A nationwide population-based study

Background

Glomerular hyperfiltration may be a clinical phenotype of endothelial dysfunction. Endothelial dysfunction may cause vascular dementia through the deterioration of cerebral blood flow. We aimed to identify the risk of dementia in people with glomerular hyperfiltration.

Methods

Using the Korean National Health Information Database, we included subjects aged ≥45 years who underwent national health screening examinations between 2012 and 2015 and who had no previous history of end-stage renal disease or dementia (n = 2,244,582). The primary exposure was glomerular hyperfiltration. We divided the subjects into groups by sex and five-year age intervals and categorized each group into 8 intervals according to estimated glomerular filtration (eGFR). The subjects with an eGFR ≥95^th percentile in each group were defined as the hyperfiltration group. The outcomes were development of all types of dementia, Alzheimer's dementia and vascular dementia. Multivariable Cox proportional hazards models were used to analyze the hazard ratios (HRs) for outcomes.

Results

The Hyperfiltration group showed a higher risk for the development of all types of dementia [adjusted HR 1.09 (95% CI, 1.03–1.15)] and vascular dementia [adjusted HR 1.33 (95% CI, 1.14–1.55)] than the reference group. However, the association between hyperfiltration and Alzheimer's dementia was not statistically significant.

Conclusions

Glomerular hyperfiltration may be associated with dementia. In this respect, subjects with glomerular hyperfiltration should be monitored more closely for signs and symptoms of dementia.

Associations between Triglyceride-Glucose Index and Micro- and Macro-angiopathies in Type 2 Diabetes Mellitus

The aim of this study was to investigate the associations between the triglyceride-glucose (TyG) index, a marker of insulin resistance, and microangiopathies and macroangiopathies in patients with type 2 diabetes mellitus (DM). Our study enrolled 1990 type 2 diabetic patients from local hospitals in Taiwan during the period of 2002–2004. Multivariate logistic regression analysis was used to identify the factors related to microangiopathies, macroangiopathiess and TyG index. The patients were stratified by TyG index quartile (Q1–Q4). Adjusted odds ratios (aORs) of albuminuria for Q3 versus Q1 and Q4 versus Q1 were 1.424 (95% confidence interval [CI], 1.062–1.910, p = 0.018) and 1.948 (95% CI, 1.437–2.642, p < 0.001), respectively. The aOR of cerebrovascular disease (CVA) was 2.264 for Q4 versus Q1 (95% CI, 1.243–4.122, p = 0.008), but there were no significant associations with diabetic retinopathy (DR), coronary artery disease (CAD) or peripheral artery occlusive disease (PAOD). Significant stepwise increases were found in CVA (p = 0.0013) and albuminuria ≥30 mg/g (p < 0.001) corresponding to TyG index quartiles, but not DR (p = 0.573), CAD (p = 0.880) or PAOD (p = 0.223). There was a significant association between a high TyG index and a high risk of microalbuminuria and CVA in the study cohort. Further studies to investigate the use of medications in patients with DM to prevent micro- and macro-angiopathies are thus warranted.

Insulin Sensitivity and Renal Hemodynamic Function in Metformin-Treated Adults With Type 2 Diabetes and Preserved Renal Function

OBJECTIVE

Impaired insulin sensitivity is associated with hyperfiltration (i.e., elevated glomerular filtration rate [GFR]) in adolescents with type 2 diabetes (T2D) and adults with prediabetes. Yet, these relationships are based on studies that relied on estimated GFR (eGFR), estimates of insulin sensitivity, or both. We aimed to verify the relationship between insulin sensitivity and renal hemodynamic function by gold standard methods in adults with T2D.

RESEARCH DESIGN AND METHODS

Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp (M value) (glucose infusion rate in mg/kg_lean/min) and renal hemodynamic function by urinary inulin (GFR) and para-aminohippuric acid (effective renal plasma flow [ERPF]) clearances in participants with T2D without overt kidney disease. Filtration fraction (FF) (GFR/ERPF) was calculated. Relationships between insulin sensitivity and renal hemodynamic parameters were examined by multivariable linear regression. Renal hemodynamic parameters were examined across tertiles of M values.

RESULTS

We tested 44 adults with T2D, of whom 77% were male, with mean ± SD age 63 ± 7 years, BMI 31.2 ± 4.0 kg/m², and HbA_1c 7.4 ± 0.6%. Average GFR was 110 ± 26 mL/min, with an FF of 22.1 ± 2.8% and median 24-h urinary albumin excretion of 11.3 mg (interquartile range 5.8-17.0). Average M value was 5.6 ± 2.9 mg/kg_lean/min. Insulin sensitivity inversely correlated with GFR (r = -0.44, P < 0.01) and FF (r = -0.40, P < 0.01), and these associations remained significant after multivariable adjustments for age, sex, renin-angiotensin system inhibitor use, and HbA_1c. In addition, GFR, FF, and urinary albumin excretion were highest in the participants in the lowest M value tertile.

CONCLUSIONS

For the first time, we demonstrate that impaired insulin sensitivity is associated with intrarenal hemodynamic dysfunction by gold standard techniques in adults with T2D treated with metformin monotherapy.

Baseline High Blood Pressure is Associated with Clinico-Pathologic Findings and Later Renal Progression in Chronic Glomerulonephritis

Background

Several factors had been suggested to contribute to the development of hypertension in chronic glomerulonephritis (GN). This study was conducted to find the association of baseline blood pressure (BP) with pathophysiologic findings and later renal progression in chronic GN.

Methods

Clinico-pathological findings including serum creatinine (Cr), proteinuria, pathological findings, and urinary Na excretion were analyzed in a total of 233 patients with IgA nephropathy from The Kyung-Hee Cohort of GN. Glomerular surface area (GSA) was measured by imaging analysis and urine angiotensinogen (AGT) concentrations by human ELISA kits.

Results

Systolic BP was ≥130mmHg in 124 patients (53%). Systolic BP was negatively correlated with follow-up eGFR (r=−0.32, p<0.0001) and positively serum uric acid concentrations, while it had no significant relationships with initial serum Cr and eGFR. As compared with patients with systolic BP<130 mmHg, those with ≥130 mmHg were older and showed higher serum Cr, proteinuria, 24 hr urinary Na excretion, mean GSA, and T-I fibrosis, lower follow-up eGFR, and steeper decline in slope of eGFR. The results in patients with normal serum Cr concentrations were comparable to those in whole group. Systolic BP was positively correlated with age, baseline and follow-up proteinuria, serum uric acid concentrations and IgM deposit and negatively with follow-up eGFR. In subgroup analysis, systolic BP was also positively correlated with mean GSA and urinary AGT concentrations.

Conclusion

This study showed that baseline systolic BP is related to urinary Na excretion, glomerulomegaly, T-I fibrosis and later renal progression in patients with IgA nephropathy.

Coffee Consumption and Kidney Function: A Mendelian Randomization Study

RATIONALE & OBJECTIVE

Chronic kidney disease (CKD) is a leading cause of morbidity and mortality worldwide, with limited strategies for prevention and treatment. Coffee is a complex mixture of chemicals, and consumption has been associated with mostly beneficial health outcomes. This work aimed to determine the impact of coffee consumption on kidney function.

STUDY DESIGN

Genome-wide association study (GWAS) and Mendelian randomization.

SETTING & PARTICIPANTS

UK Biobank baseline data were used for a coffee consumption GWAS and included 227,666 participants. CKDGen Consortium data were used for kidney outcomes and included 133,814 participants (12,385 cases of CKD) of mostly European ancestry across various countries.

EXPOSURE

Coffee consumption.

OUTCOMES

Estimated glomerular filtration rate (eGFR), CKD GFR categories 3 to 5 (G3-G5; eGFR<60mL/min/1.73m²), and albuminuria.

ANALYTICAL APPROACH

GWAS to identify single-nucleotide polymorphisms (SNPs) associated with coffee consumption in UK Biobank and use of those SNPs in Mendelian randomization analyses of coffee consumption and kidney outcomes in CKDGen.

RESULTS

2,126 SNPs were associated with coffee consumption (P<5×10^-8), 25 of which were independent and available in CKDGen. Drinking an extra cup of coffee per day conferred a protective effect against CKD G3-G5 (OR, 0.84; 95% CI, 0.72-0.98; P=0.03) and albuminuria (OR, 0.81; 95% CI, 0.67-0.97; P=0.02). An extra cup was also associated with higher eGFR (β=0.022; P=1.6×10^-6) after removal of 3 SNPs responsible for significant heterogeneity (Cochran Q P = 3.5×10^-15).

LIMITATIONS

Assays used to measure creatinine and albumin varied between studies that contributed data and a sex-specific definition was used for albuminuria rather than KDIGO guideline recommendations.

CONCLUSIONS

This study provides evidence of a beneficial effect of coffee on kidney function. Given widespread coffee consumption and limited interventions to prevent CKD incidence and progression, this could have significant implications for global public health in view of the increasing burden of CKD worldwide.

Can childhood obesity influence later chronic kidney disease?

Childhood overweight and obesity affects more and more children. Whilst associations of childhood overweight with later outcomes such as hypertension, diabetes and cardiovascular disease have been well documented, less is known about the association of childhood overweight and obesity with kidney disease. We review the existing evidence for the association of childhood obesity with markers of childhood and adult kidney disease. Whilst there is some evidence for an association, studies have not been able to distinguish between childhood being a sensitive time to develop later kidney problems, or whether observed associations of childhood obesity with poor outcomes are driven by greater lifelong exposure to obesity.

Human nephron number, hypertension, and renal pathology

Recent studies have reported that total nephron number varies widely in human kidneys and some racial groups with low nephron number have a higher incidence of hypertension and kidney disease. Importantly, nephrogenesis normally reaches completion at about 34-36 weeks gestation, with no new nephrons formed for the lifetime in humans after this time. Although the loss of glomeruli varies among individuals due to aging, blood pressure, or additional inducers of kidney injury, much of the variation in nephron number is nowadays thought to be present at birth. According to the hyperfiltration hypothesis, this subsequent nephron loss results in compensatory hyperfiltration and/or hypertension of remaining glomeruli, thereby contributing to increased susceptibility to systemic hypertension. However, recent studies have suggested that the association between a low nephron number and systemic hypertension is not a universal finding. In most studies to date, nephron counts were performed on kidneys obtained at autopsy. Several recent studies have attempted to estimate nephron number in living human subjects, but further work is required to obtain accurate and precise estimates of nephron number using these noninvasive methods. Longitudinal studies in living humans have the potential to reveal associations between nephron number and hypertension/renal pathology.

Renal hyperfiltration defined by high estimated glomerular filtration rate: A risk factor for cardiovascular disease and mortality

Renal hyperfiltration, defined as an increased glomerular filtration rate above normal values, is associated with early phases of kidney disease in the setting of various conditions such as obesity and diabetes. Although it is recognized that glomerular hyperfiltration, that is, increased filtration per nephron unit (usually studied at low glomerular filtration levels and often referred to as single nephron hyperfiltration), is a risk factor for the progression of chronic kidney disease, the implications of having renal hyperfiltration for cardiovascular disease and mortality risk are incompletely understood. Recent evidence from diverse populations, including healthy individuals and patients with diabetes or established cardiovascular disease, suggests that renal hyperfiltration is associated with a higher risk of cardiovascular disease and all-cause mortality. In this review, we critically summarize the existing studies, discuss possible mechanisms, and describe the remaining gaps in our knowledge regarding the association of renal hyperfiltration with cardiovascular disease and mortality risk.

Association Between Body Composition and Glomerular Hyperfiltration Among Chinese Adults

High body mass index (BMI) is the most common parameter to assess excess adiposity, and has been linked to glomerular hyperfiltration (GH). However, BMI may be misleading in the estimation of body fat content due to its inability to discriminate between body fat and lean mass. In recent years, the convenient biological impedance analysis has made prediction of certain diseases somewhat feasible and accessible using body composition (BC). Accordingly, we conducted a cross-sectional study to explore the association between BC and GH among Chinese adult population. A total of 6902 adults (aged 38.6 ± 8.3 years, 70.1% males) who consecutively visited the Health Checkup Clinic were enrolled. BC including fat mass and lean body mass (LBM) was evaluated by biological impedance analysis. The upper quartile of eGFR which exceeded 117.3 mL/min/1.73 m² was defined as GH, in comparison with the lower three quartiles (control group). As a categorical outcome, GH subjects had higher fat/LBM than the control group, which was 34.7 ± 10.9 (%) vs. 34.0 ± 10.5 (%), P = 0.01; however, the BMI in GH group was lower than in the control group, which was 24.5 ± 3.7 (%) vs. 24.9 ± 3.6 (%), P < 0.001. Fat/height and Fat/BSA were not significantly different between the two groups. Moreover, after adjusting for potential confounders, fat/LBM significantly correlated with GH (OR = 2.09, 95% CI, 1.11 to 3.93). The study revealed that fat/LBM significantly correlated with GH among Chinese adult population, which highlights that adiposity might be an important and potentially modifiable determinant of GH.

Survival outcomes for patients with surgically induced end-stage renal disease

INTRODUCTION

While medically induced end-stage renal disease (m-ESRD) has been well-studied, outcomes in patients with surgically induced ESRD (s-ESRD) are unknown. We sought to quantitatively compare the non-oncological outcomes for s-ESRD and m-ESRD in a large, population-based cohort.

METHODS

Medicare patients >65 years old initiating hemodialysis were identified using the U.S. Renal Data System database (2000-2012). Metastatic cancer, prior transplant history, and nephrectomy for polycystic kidney disease were exclusion criteria. Patients were classified as having s-ESRD or m-ESRD based on hospital and physician claims for nephrectomy within a year preceding the onset of maintenance hemodialysis. Outcomes included non-cancer mortality (NCM), overall survival (OS), cardiovascular event (CVE), and renal transplantation. Time-to-event analyses were performed using Kaplan-Meier and cumulative incidence curves, and multivariable Cox and Fine-and-Grey regression models.

RESULTS

The cohort included 312 612 patients, of whom 1648 (0.53%) had s-ESRD. Compared to m-ESRD patients, s-ESRD patients had a significantly lower five-year cumulative incidence of NCM (68% vs. 80%; p<0.001) and CVE (62% vs. 68%; p<0.001), with a correspondingly higher probability of OS (22% vs. 17%; p<0.001) and rate of renal transplantation (3.6% vs. 2.0%; p<0.001). On multivariable analyses, s-ESRD remained associated with lower risks of NCM (p<0.001) and CVE (p<0.001), improved OS (p<0.001), and higher chance of renal transplantation (p<0.001).

CONCLUSIONS

While outcomes for s-ESRD appear more favorable than m-ESRD, s-ESRD is still associated with a substantial risk of NCM and CVE, and a low incidence of renal transplantation in Medicare patients >65 years old. These non-oncological outcomes are worth considering in patients potentially facing postoperative ESRD.

Effects of the sodium-glucose co-transporter 2 inhibitor dapagliflozin in patients with type 2 diabetes and Stages 3b-4 chronic kidney disease

Background

The sodium–glucose co-transporter 2 inhibitor dapagliflozin decreases haemoglobin A1c (HbA1c), body weight, blood pressure (BP) and urinary albumin:creatinine ratio (UACR) in patients with type 2 diabetes. The efficacy and safety of this drug have not been properly defined in patients with type 2 diabetes and Stages 3b–4 chronic kidney disease (CKD).

Methods

In a pooled analysis of 11 phase 3 randomized controlled clinical trials, we determined least square mean changes in HbA1c, body weight, BP, estimated glomerular filtration rate (eGFR) and UACR over 102 weeks in patients with type 2 diabetes and an eGFR between 12 to less than 45 mL/min/1.73 m² receiving placebo (n = 69) or dapagliflozin 5 or 10 mg (n = 151). Effects on UACR were determined in a subgroup of patients with baseline UACR ≥30 mg/g (n = 136).

Results

Placebo-corrected changes in HbA1c with dapagliflozin 5 and 10 mg were 0.03% [95% confidence interval (CI) −0.3–0.3] and 0.03% (95% CI −0.2–0.3) during the overall 102-week period. Dapagliflozin 5 and 10 mg compared with placebo reduced UACR by − 47.1% (95% CI −64.8 to − 20.6) and −38.4% (95% CI −57.6 to − 10.3), respectively. Additionally, dapagliflozin 5 and 10 mg compared with placebo reduced BP and body weight. eGFR increased with placebo during the first 4 weeks but did not change with dapagliflozin. There were no between-group differences in eGFR at the end of follow-up. Adverse events associated with renal function occurred more frequently in the dapagliflozin 10-mg group. These events were mainly asymptomatic increases in serum creatinine.

Conclusions

Dapagliflozin did not decrease HbA1c in patients with type 2 diabetes and Stages 3b–4 CKD, but decreased UACR, BP and body weight to a clinically meaningful extent. These results support a large outcome trial in this population to confirm long-term safety and efficacy in reducing adverse clinical endpoints.

Combined exposure to lead, cadmium, mercury, and arsenic and kidney health in adolescents age 12-19 in NHANES 2009-2014

BACKGROUND

Occupational and environmental exposures to toxic metals are established risk factors for the development of hypertension and kidney disease in adults. There is some evidence of developmental metal nephrotoxicity in children and from animal studies; however, to our knowledge no previous studies have examined associations between co-exposure to nephrotoxic environmental metals and children's kidney health.

OBJECTIVE

The objective of this study was to assess the association between co-exposure to lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As), measured in urine and blood, and kidney parameters in US adolescents.

METHODS

We performed a cross-sectional analysis of a subsample of 2709 children aged 12-19 participating in the National Health and Nutrition Examination Survey (NHANES) between 2009 and 2014. We analyzed urine levels of 4 nephrotoxic metals selected a priori (As, Cd, Pb and Hg), U_mix, and 3 nephrotoxic metals in blood (Cd, Pb, and Hg), B_mix, using a weighted quantile sum (WQS) approach. We applied WQS regression to analyze the association of B_mix and U_mix with estimated glomerular filtration rate (eGFR), serum uric acid (SUA), urine albumin, blood urea nitrogen (BUN), and systolic blood pressure (SBP), adjusting for sex, race/ethnicity, age, head of household's education level, height, BMI, serum cotinine, and NHANES cohort year. U_mix and urine albumin models were also adjusted for urine creatinine, and B_mix models were also adjusted for fish consumption. Subanalyses included stratification by sex and an arsenic-only model including six speciated forms of As measured in urine.

RESULTS

In WQS regression models, each decile increase of U_mix was associated with 1.6% (95% CI: 0.5, 2.8) higher BUN, 1.4% (95% CI: 0.7, 2.0) higher eGFR, and 7.6% (95% CI: 2.4, 13.1) higher urine albumin. The association between U_mix and BUN was primarily driven by As (72%), while the association with eGFR was driven by Hg (61%), and Cd (17%), and the association with urine albumin was driven by Cd (37%), Hg (33%), and Pb (25%). There was no significant relationship between U_mix and SUA or SBP. In WQS models using the combined blood metals, B_mix, each decile increase of B_mix was associated with 0.6% (95% CI: 0.0, 1.3) higher SUA; this association was driven by Pb (43%), Hg (33%), and Cd (24%) and was marginally significant (p = 0.05). No associations were observed between B_mix and urine albumin, eGFR, BUN, or SBP.

CONCLUSIONS

The findings suggest metals including As, Pb, Hg, Cd and their combinations may affect renal parameters, although potential reverse causation cannot be ruled out due to the cross-sectional study design. Implications of early life low-level exposure to multiple metals on kidney function may have far-reaching consequences later in life in the development of hypertension, kidney disease, and renal dysfunction. Longitudinal studies should further evaluate these relationships.

Glomerular hyperfiltration may be a novel risk factor of restrictive spirometry pattern: Analysis of the Korea National Health and Nutrition Examination Survey (KNHANES) 2009-2015

BACKGROUND AND OBJECTIVES

There have been limited studies regarding the association between glomerular hyperfiltration (GHF) and restrictive spirometry pattern (RSP) in Korean adults.

METHODS

We used data of 23,189 adults from the Korea National Health and Nutritional Examination Survey 2009-2015 with a complete data set including spirometry, serum creatinine, and anthropometric measurements. Spirometry data included the forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). We defined GHF as the >90th percentile of age & sex adjusted estimated glomerular filtration rate (eGFR), and RSP was defined as an FVC <80%-predicted value and an FEV1/FVC ratio ≥0.7.

RESULTS

Participants with RSP showed higher blood pressure, fasting glucose, and triglyceride, reduced high density lipoprotein cholesterol, and central obesity, which resulted in a higher prevalence of metabolic syndrome (MetS) compared to those without RSP. Multivariate logistic regression revealed that the odds for RSP were significantly increased with an increased number of MetS components. In addition, increased eGFR was associated with decreased FVC, showing an inverted J-shaped relationship in a multivariate generalized additive model analysis. In the multivariate logistic regression analysis, the adjusted odds ratio and 95% confidence interval of GHF for RSP was 1.184 (1.026-1.368, P = 0.021), which was evident in groups without metabolic disorders.

CONCLUSIONS

We concluded that GHF was associated with increased odds for RSP, particularly in groups without metabolic disorders. Further prospective studies are needed to confirm our study results.

The diabetes pandemic suggests unmet needs for 'CKD with diabetes' in addition to 'diabetic nephropathy'-implications for pre-clinical research and drug testing

Curing 'diabetic nephropathy' is considered an unmet medical need of high priority. We propose to question the concept of 'diabetic nephropathy' that implies diabetes as the predominant cause of kidney disease, which may not apply to the majority of type 2 diabetics approaching end-stage kidney disease. With the onset of diabetes, hyperglycaemia/sodium-glucose co-transporter-2-driven glomerular hyperfiltration promotes nephron hypertrophy, which, however, on its own, causes proteinuria not before a decade later, probably because podocyte hypertrophy can usually accommodate an increase in the filtration surface. In contrast, precedent chronic kidney disease (CKD), that is, few nephrons per body mass, e.g. due to poor nephron endowment from birth, obesity, pregnancy, or renal ageing or injury-related nephron loss, usually precedes the onset of type 2 diabetes. This applies in particular in older adults, and each on its own, but especially in combination, further aggravates single nephron hyperfiltration and glomerular hypertrophy. Whenever this additional hyperglycaemia-driven enlargement of the glomerular filtration surface exceeds the capacity of podocytes for hypertrophy, podocytes detachment leads to glomerulosclerosis and nephron loss, i.e. CKD progression. Animal models of 'diabetic nephropathy' based only on hyperglycaemia do not mimic this aspect and therefore poorly predict outcomes of clinical trials usually performed on elderly CKD patients with type 2 diabetes. Thus, we advocate the use of renal mass (nephron) ablation in type 2 diabetic animals to better mimic the pathophysiology of 'CKD with diabetes' in the target patient population and the use of the glomerular filtration rate as a primary endpoint to more reliably predict trial outcomes.

High levels of fasting glucose and glycosylated hemoglobin values are associated with hyperfiltration in a Spanish prediabetes cohort. The PREDAPS Study

AIM

This study aimed to investigate whether different levels of fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) in prediabetes are associated with hyperfiltration.

METHODS

A prospective cohort of 2,022 individuals aged 30-74 years took part in the PREDAPS Study. One cohort of 1,184 participants with prediabetes and another cohort of 838 participants with normal FPG and normal HbA1c were followed for 5 years. Hyperfiltration was defined as an estimated glomerular filtration rate (eGFR) above the age- and gender-specific 95th percentile for healthy control participants, while hypofiltration was defined as an eGFR below the 5th percentile. The prevalence of hyperfiltration was compared for different levels of prediabetes: level 1 of prediabetes: FPG <100 mg/dL plus HbA1c 5.7-6.0% or FPG 100-109 mg/dL plus HbA1c < 5.7%; level 2 of prediabetes: FPG <100 mg/dL plus HbA1c 6.1-6.4% or FPG 100-109 mg/dL plus HbA1c 5.7-6.0% or FPG 110-125 mg/dL plus HbA1c <5.7% and level 3 of prediabetes: FPG 100-109 mg/dL plus HbA1c 6.1-6.4% or FPG 110-125 mg/dL plus HbA1c 5.7-6.4%.

RESULTS

The participants with hyperfiltration were significantly younger, had a higher percentage of active smokers, and lower levels of hemoglobin and less use of ACEIs or ARBs. Only level 3 prediabetes based on FPG 100-109 mg/dL plus HbA1c 6.1-6.4% or FPG 110-125 mg/dL plus HbA1c 5.7-6.4% had a significantly higher odds ratio (OR) of hyperfiltration (OR 1.69 (1.05-2.74); P < 0.001) compared with no prediabetes (FPG < 100 mg/dL and HbA1c < 5.7%) after adjustment for different factors. The odds ratios for different levels of HbA1c alone in prediabetes increased progressively, but not significantly.

CONCLUSIONS

Level 3 of prediabetes based on FPG 100-109 mg/dL plus HbA1c 6.1-6.4% or FPG 110-125 mg/dL plus HbA1c 5.7-6.4% had a significantly higher OR of hyperfiltration compared with participants without prediabetes.

Self-Reported Incident Hypertension and Long-Term Kidney Function in Living Kidney Donors Compared with Healthy Nondonors

BACKGROUND AND OBJECTIVES

The risk of hypertension attributable to living kidney donation remains unknown as does the effect of developing postdonation hypertension on subsequent eGFR. We sought to understand the association between living kidney donation, hypertension, and long-term eGFR by comparing donors with a cohort of healthy nondonors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We compared 1295 living kidney donors with median 6 years of follow-up with a weighted cohort of 8233 healthy nondonors. We quantified the risk of self-reported hypertension using a parametric survival model. We examined the association of hypertension with yearly change in eGFR using multilevel linear regression and clustering by participant, with an interaction term for race.

RESULTS

Kidney donation was independently associated with a 19% higher risk of hypertension (adjusted hazard ratio, 1.19; 95% confidence interval, 1.01 to 1.41; P=0.04); this association did not vary by race (interaction P=0.60). For white and black nondonors, there was a mean decline in eGFR (-0.4 and -0.3 ml/min per year, respectively) that steepened after incident hypertension (-0.8 and -0.9 ml/min per year, respectively; both P<0.001). For white and black kidney donors, there was a mean increase in eGFR after donation (+0.4 and +0.6 ml/min per year, respectively) that plateaued after incident hypertension (0 and -0.2 ml/min per year, respectively; P=0.07 and P=0.01, respectively, after hypertension).

CONCLUSIONS

Kidney donors are at higher risk of hypertension than similar healthy nondonors, regardless of race. Donors who developed hypertension had a plateau in the usual postdonation increase of eGFR.

Inverse correlation between vascular endothelial growth factor back-filtration and capillary filtration pressures

Background

Vascular endothelial growth factor A (VEGF) is an essential growth factor during glomerular development and postnatal homeostasis. VEGF is secreted in high amounts by podocytes into the primary urine, back-filtered across the glomerular capillary wall to act on endothelial cells. So far it has been assumed that VEGF back-filtration is driven at a constant rate exclusively by diffusion.

Methods

In the present work, glomerular VEGF back-filtration was investigated in vivo using a novel extended model based on endothelial fenestrations as surrogate marker for local VEGF concentrations. Single nephron glomerular filtration rate (SNGFR) and/or local filtration flux were manipulated by partial renal mass ablation, tubular ablation, and in transgenic mouse models of systemic or podocytic VEGF overexpression or reduction.

Results

Our study shows positive correlations between VEGF back-filtration and SNGFR as well as effective filtration rate under physiological conditions along individual glomerular capillaries in rodents and humans.

Conclusion

Our results suggest that an additional force drives VEGF back-filtration, potentially regulated by SNGFR.

Comparison of HbA1c levels and body mass index for prevention of diabetic kidney disease: A retrospective longitudinal study using outpatient clinical data in Japanese patients with type 2 diabetes mellitus

AIM

This study examined the association among the onset of diabetic kidney disease (DKD), blood glucose levels (HbA1_C), and body mass index (BMI) in Japanese patients with type 2 diabetes mellitus.

METHODS

Patients eligible for this study included those with type 2 diabetes who visited the outpatient clinic at Kawasaki Medical School Hospital between 2000 and 2018 and were followed up for more than two years. The Cox proportional hazards model was used in four categories of subjects: at the beginning of the follow-up period, "controlled" or "uncontrolled" glycemic control based on HbA1c and "overweight" or "non-overweight" based on BMI.

RESULTS

After dividing the participants into four categories according to HbA1c (lower than 7.0% (C) or higher (U)), and BMI (25 kg/m² or higher (O) or lower (N)), hazard ratios for groups CO, UN, and UO were 1.40 (95% CI 1.03-1.90, P = 0.030), 1.40 (1.04-1.88, P = 0.027), and 1.54 (1.12-2.11, P = 0.008), respectively, compared with the CN reference group, after adjustment was made for age, sex, duration of diabetes, and medication for hypertension or dyslipidemia.

CONCLUSION

Maintenance of both an HbA1c level lower than 7.0% and a BMI lower than 25 kg/m² was important for the prevention of DKD in Japanese patients with type 2 diabetes mellitus. Both factors had a similar effect on DKD in this study.

The Role of Fibroblast Growth Factor 23 in Inflammation and Anemia

In patients with chronic kidney disease (CKD), adverse outcomes such as systemic inflammation and anemia are contributing pathologies which increase the risks for cardiovascular mortality. Amongst these complications, abnormalities in mineral metabolism and the metabolic milieu are associated with chronic inflammation and iron dysregulation, and fibroblast growth factor 23 (FGF23) is a risk factor in this context. FGF23 is a bone-derived hormone that is essential for regulating vitamin D and phosphate homeostasis. In the early stages of CKD, serum FGF23 levels rise 1000-fold above normal values in an attempt to maintain normal phosphate levels. Despite this compensatory action, clinical CKD studies have demonstrated powerful and dose-dependent associations between FGF23 levels and higher risks for mortality. A prospective pathomechanism coupling elevated serum FGF23 levels with CKD-associated anemia and cardiovascular injury is its strong association with chronic inflammation. In this review, we will examine the current experimental and clinical evidence regarding the role of FGF23 in renal physiology as well as in the pathophysiology of CKD with an emphasis on chronic inflammation and anemia.

CKD in diabetes: diabetic kidney disease versus nondiabetic kidney disease

The increasing global prevalence of type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) has prompted research efforts to tackle the growing epidemic of diabetic kidney disease (DKD; also known as diabetic nephropathy). The limited success of much of this research might in part be due to the fact that not all patients diagnosed with DKD have renal dysfunction as a consequence of their diabetes mellitus. Patients who present with CKD and diabetes mellitus (type 1 or type 2) can have true DKD (wherein CKD is a direct consequence of their diabetes status), nondiabetic kidney disease (NDKD) coincident with diabetes mellitus, or a combination of both DKD and NDKD. Preclinical studies using models that more accurately mimic these three entities might improve the ability of animal models to predict clinical trial outcomes. Moreover, improved insights into the pathomechanisms that are shared by these entities - including sodium-glucose cotransporter 2 (SGLT2) and renin-angiotensin system-driven glomerular hyperfiltration and tubular hyper-reabsorption - as well as those that are unique to individual entities might lead to the identification of new treatment targets. Acknowledging that the clinical entity of CKD plus diabetes mellitus encompasses NDKD as well as DKD could help solve some of the urgent unmet medical needs of patients affected by these conditions.

Association Between Acute Fall in Estimated Glomerular Filtration Rate After Treatment for Primary Aldosteronism and Long-Term Decline in Renal Function

Primary aldosteronism causes renal structural damage after glomerular hyperfiltration, and primary aldosteronism-specific treatment leads to an acute fall in estimated glomerular filtration rate (eGFR). We investigated whether this change affected the long-term eGFR slope in a retrospective cohort from the multicenter Japan Primary Aldosteronism Study. We allocated patients with primary aldosteronism to the adrenalectomy (n=202) and MR (mineralocorticoid receptor) antagonist (n=303) groups based on their treatment history and analyzed the association between the initial eGFR fall and long-term eGFR slope. The increased age, low serum potassium levels, high eGFR, and high plasma aldosterone levels were independent predictors for a large initial eGFR fall in both groups. Our analysis of tertiles based on the initial eGFR fall revealed that in the MR antagonist group, patients with a small initial eGFR fall had a significantly steeper long-term eGFR slope than those with a large initial fall (tertile 1 versus 2, P=0.025; tertile 1 versus 3, P=0.017). These associations were not identified in the adrenalectomy group. Thus, the smaller the acute fall in eGFR by initiation of MR antagonists, the greater was the rate of long-term eGFR decline. While the acute fall in eGFR induced by primary aldosteronism-specific treatment is occasionally a clinical concern, our findings highlight the favorable implications of the acute fall with respect to long-term renal outcomes.

Chronic kidney disease in patients with obstructive sleep apnea. A narrative review

Prevalence of both chronic kidney disease (CKD) and obstructive sleep apnea (OSA) is continuously increasing. Moreover, the prevalence of OSA increases as kidney function declines and is higher among patients with end-stage renal disease (ESRD). In addition, OSA is recognized as a potential nontraditional risk factor for development and progression of CKD. Continuous positive airway pressure (CPAP) plays a pivotal role in the management of OSA, eliminating patients' symptoms and improving their quality of life. Recent studies suggested that CPAP treatment may have beneficial effects on kidney function among patients with OSA. This narrative review summarizes the existing knowledge on the association between CKD and OSA, with emphasis on the epidemiology, the pathophysiology of the development of CKD in OSA and vice versa, as well as the effect of CPAP on renal function.

Preeclampsia and risk of end stage kidney disease: A Swedish nationwide cohort study

BACKGROUND

Preeclampsia has been suggested to increase the risk of end-stage kidney disease (ESKD); however, most studies were unable to adjust for potential confounders including pre-existing comorbidities such as renal disease and cardiovascular disease (CVD). We aimed to examine the association between preeclampsia and the risk of ESKD in healthy women, while taking into account pre-existing comorbidity and potential confounders.

METHODS AND FINDINGS

Using data from the Swedish Medical Birth Register (MBR), women who had singleton live births in Sweden between 1982 and 2012, including those who had preeclampsia, were identified. Women with a diagnosis of chronic kidney disease (CKD), CVD, hypertension, or diabetes prior to the first pregnancy were excluded. The outcome was a diagnosis of ESKD, identified from the Swedish Renal Registry (SRR) from January 1, 1991, onwards along with the specified cause of renal disease. We conducted Cox proportional hazards regression analysis to examine the association between preeclampsia and ESKD adjusting for several potential confounders: maternal age, body mass index (BMI), education, native country, and smoking. This analysis accounts for differential follow-up among women because women had different lengths of follow-up time. We performed subgroup analyses according to preterm preeclampsia, small for gestational age (SGA), and women who had 2 pregnancies with preeclampsia in both. The cohort consisted of 1,366,441 healthy women who had 2,665,320 singleton live births in Sweden between 1982 and 2012. At the first pregnancy, women's mean (SD) age and BMI were 27.8 (5.13) and 23.4 (4.03), respectively, 15.2% were smokers, and 80.7% were native Swedish. The overall median (interquartile range [IQR]) follow-up was 7.4 years (3.2-17.4) and 16.4 years (10.3-22.0) among women with ESKD diagnosis. During the study period, 67,273 (4.9%) women having 74,648 (2.8% of all pregnancies) singleton live births had preeclampsia, and 410 women developed ESKD with an incidence rate of 1.85 per 100,000 person-years. There was an association between preeclampsia and ESKD in the unadjusted analysis (hazard ratio [HR] = 4.99, 95% confidence interval [CI] 3.93-6.33; p < 0.001), which remained in the extensively adjusted (HR = 4.96, 95% CI 3.89-6.32, p < 0.001) models. Women who had preterm preeclampsia (adjusted HR = 9.19; 95% CI 5.16-15.61, p < 0.001) and women who had preeclampsia in 2 pregnancies (adjusted HR = 7.13, 95% CI 3.12-16.31, p < 0.001) had the highest risk of ESKD compared with women with no preeclampsia. Considering this was an observational cohort study, and although we accounted for several potential confounders, residual confounding cannot be ruled out.

CONCLUSIONS

The present findings suggest that women with preeclampsia and no major comorbidities before their first pregnancy are at a 5-fold increased risk of ESKD compared with parous women with no preeclampsia; however, the absolute risk of ESKD among women with preeclampsia remains small. Preeclampsia should be considered as an important risk factor for subsequent ESKD. Whether screening and/or preventive strategies will reduce the risk of ESKD in women with adverse pregnancy outcomes is worthy of further investigation.

Comparison of the Serum Metabolic Fingerprint of Different Exercise Modes in Men with and without Metabolic Syndrome

Exercise plays a beneficial role in the treatment of metabolic syndrome (MetS). Metabolomics can provide new insights and facilitate the optimization of exercise prescription. This study aimed to investigate whether the response of the human serum metabolic fingerprint to exercise depends on exercise mode or the presence of MetS. Twenty-three sedentary men (nine with MetS and fourteen healthy) completed four trials: Resting, high-intensity interval exercise (HIIE), continuous moderate-intensity exercise (CME), and resistance exercise (RE). Blood samples were collected pre-exercise, immediately after exercise, and 1 h post-exercise for targeted metabolomic analysis in serum by liquid chromatography–mass spectrometry. Time exerted the strongest differentiating effect, followed by exercise mode. The largest changes from baseline were found in the immediate post-exercise samples. RE caused the strongest responses overall, followed by HIIE, while CME had minimal effect. Unlike previous results in urine, no valid model could separate the two groups in serum. Exercise exerted a beneficial effect on prominent serum biomarkers of metabolic risks, such as branched-chain amino acids, alanine, acetylcarnitine, choline, and betaine. These findings contribute to the ongoing research efforts to map the molecular responses to exercise and to optimize exercise guidelines for individuals at cardiometabolic risk.

High-protein diet with renal hyperfiltration is associated with rapid decline rate of renal function: a community-based prospective cohort study

Background

The effect of a high-protein diet with renal hyperfiltration (RHF) on decline of kidney function has rarely been explored. We investigated the association between a high-protein diet, RHF and declining kidney function.

Methods

A total of 9226 subjects from the Korean Genome and Epidemiology Study, a community-based prospective study (2001–14), were enrolled and classified into quartiles according to daily amount of protein intake based on food frequency questionnaires. RHF was defined as estimated glomerular filtration rate (eGFR) with residuals of >95th percentile after adjustment for age, sex, history of hypertension or diabetes, height and weight. Rapid decline of renal function was defined as decline rate of eGFR >3 mL/min/1.73 m2/year.

Results

The relative risk of RHF was 3.48-fold higher in the highest than in the lowest protein intake quartile after adjustment for confounding factors [95% confidence interval (CI) 1.39–8.71]. The mean eGFR decline rate was faster as quartiles of protein intake increased. Furthermore, the highest quartile was associated with 1.32-fold increased risk of rapid eGFR decline (95% CI 1.02–1.73). When subjects were divided into two groups with or without RHF, the highest quartile was associated with a rapid decline in renal function only in RHF subjects (odds ratio 3.35; 95% CI 1.07–10.51). The sensitivity analysis using the Korean National Health and Nutrition Examination Survey (2008–15) data with 40 113 subjects showed that higher quartile was associated with increased risk for RHF.

Conclusions

A high-protein diet increases the risk of RHF and a rapid renal function decline in the general population. These findings suggest that a high-protein diet has a deleterious effect on renal function in the general population.

Increased Glomerular Filtration Rate in Early Stage of Balkan Endemic Nephropathy

Background: A previous study indicated that Balkan endemic nephropathy (BEN) patients in the early stage of the disease had significantly higher creatinine clearance (Ccr) than healthy persons. The aim of the study was to assess whether tubular creatinine secretion affects Ccr in early stages of BEN and to check the applicability of serum creatinine-based glomerular filtration rate (GFR) equations in these patients. Methods: The study involved 21 BEN patients with estimated GFR (eGFR) above 60 mL/min/1.73 m2, excluding any conditions that could affect GFR or tubular creatinine secretion, and 15 healthy controls. In all participants Ccr with and without cimetidine and iohexol clearance (mGFR) were measured and eGFR calculated using Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease Study (MDRD) equations. Glomerular hyperfiltration cutoff (GFR-HF) was calculated. Results: There was no significant difference between the groups in Ccr before and after cimetidine or for eGFR, but mGFR was significantly higher in BEN patients than in controls (122.02 ± 28.03 mL/min/1.73 m2 vs. 101.15 ± 27.32 mL/min/1.73 m2; p = 0.032). Cimetidine administration reduced Ccr by 10% in both groups. The ratio of Ccr to mGFR was significantly above one in seven BEN patients and five controls and their mGFR values were similar. Seven other patients and eight controls had this ratio equal to one, while values below one were recorded for seven more patients and two controls. mGFR of all these 14 patients was significantly higher than that of healthy controls (129.88 ± 27.52 mL/min/1.73 m2 vs. 107.43 ± 19.51 mL/min/1.73 m2; p = 0.009). Mean GFR-HF was significantly higher than mGFR in controls, but these two values were similar in BEN patients. eGFR underestimated mGFR in both BEN patients and controls. Conclusion: The ratio of Ccr to mGFR and mGFR to GFR-HF indicated that elevated mGFR in early stages of BEN could be explained by increased glomerular filtration, but tubular creatinine secretion augmented Ccr in a smaller proportion of patients, who did not differ from healthy subjects.

Elevated triglycerides rather than other lipid parameters are associated with increased urinary albumin to creatinine ratio in the general population of China: a report from the REACTION study

Background

Dyslipidaemia has always been regarded as the cornerstone of arteriosclerosis and is related to the pathogenesis of renal insufficiency. However, it is unclear which routinely available lipid parameter is related to urinary albumin to creatinine ratio (UACR). The purpose of this study was to examine the lipid abnormalities associated with UACR in the general population in China.

Methods

The present study was nested in an ongoing Risk Evaluation of cAncers in Chinese diabetic Individuals: A lONgitudinal (REACTION) study, which was designed to demonstrate the association of abnormal glucose metabolism with the risk of cancer in the Chinese population. This cross-sectional study included 34, 569 subjects (11, 390 males and 23, 179 females) from 8 different regional community cohorts, with an average age of 57.9 years. The UACR data were divided into the < 25% group, the 25–49% group, the 50–74% group, and the ≥ 75% group according to the quartile division of the centre where the subjects visited. The lipid classes were defined according to the guidelines for the prevention and treatment of dyslipidaemia in Chinese adults. Multiple logistic regression analysis was used to evaluate the association of the lipid parameters and UACR.

Results

Multivariable regression analysis revealed that compared with the other lipid parameters, triglycerides (TG) showed an adjusted odds ratio that was significant in model 1–4. This relationship was attenuated after adjusting for Haemoglobin A1c (HbA1c) and blood pressure (BP), but TG ≥ 2.3 mmol/L was still significantly associated with UACR in total subjects and in both men and women (OR: 1.131, 95% CI 1.065–1.203, P < 0.001 in total subjects; OR: 1.134, 95% CI 1.022–1.258, P = 0.017 in men; OR: 1.129, 95% CI 1.046–1.219, P = 0.002 in women). In the stratified analysis, elevated TG was significantly associated with increased urinary albumin in subjects with eGFR ≥ 90 mL/min per 1.73 m², 5.6 ≤ FBG < 7.0 or 7.8 ≤ PBG < 11.1 mmol/L, 24 ≤ BMI < 28 kg/m², 120 ≤ SBP < 140 and/or 80 ≤ DBP < 90 mmHg.

Conclusions

We conclude that high TG levels rather than total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or non-high-density lipoprotein cholesterol levels are associated with UACR in the general population in China.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0863-8) contains supplementary material, which is available to authorized users.