Proteinuria and rate of change in kidney function in a community-based population

Dietary Magnesium Intake and Proteinuria: Is There a Relationship?

The possible relationship between dietary magnesium status and proteinuria has been suggested by a number of previous studies. However, human studies on this association are limited. Therefore, the present study aimed to investigate the independent relationship between dietary magnesium intake and urinary protein excretion. The present study was a post hoc analysis of the previous randomized clinical trial that evaluated the effect of dietary phosphorus restriction on proteinuria. The baseline data of 90 participants with proteinuria and chronic kidney disease was used to measure the association between dietary magnesium intake and proteinuria. Participants were asked to record their 24-h food intake for three days a week in a questionnaire. Urinary protein to creatinine ratio (UPCR) in a random urine sample was measured to be a marker for proteinuria. Out of 90 patients included in the study, 47 were men and 43 were women. The mean ± standard deviation of age and body mass index were 59.05 ± 14.16 years and 29.02 ± 5.54 kg/m2, respectively. The patients' average daily dietary intake of energy and magnesium were 2183 kcal and 169.44 mg, respectively. A significant inverse correlation was found between the dietary intake of magnesium and UPCR (r =  - 0.219, p = 0.042). This association remained significant even after adjusting for confounding variables (β =  - 0.222, p = 0.028). The findings of the present study showed a significant inverse relationship between the magnesium intake and proteinuria. Although, the design of the current research was cross-sectional, it has provided a basis for conducting future longitudinal studies and trials to better elucidate such a relationship.

Clinical Outcomes in Patients with CKD and Rapid or Non-rapid eGFR Decline: A Report from the DISCOVER CKD Retrospective Cohort

INTRODUCTION

This analysis examined the baseline characteristics and clinical outcomes of patients with chronic kidney disease (CKD) and rapid or non-rapid estimated glomerular filtration rate (eGFR) decline, using retrospective data from DISCOVER CKD (ClinicalTrials.gov, NCT04034992).

METHODS

Data (2008-2020) were extracted from UK Clinical Practice Research Datalink, US TriNetX, US Limited Claims and Electronic Health Record Dataset, and Japan Medical Data Vision. Patients with CKD (two consecutive eGFR measures < 75 mL/min/1.73 m2 recorded 90-730 days apart) were included. Rapid eGFR decline was defined as an annual decline of > 4 mL/min/1.73 m2 at 2 years post-index; non-rapid eGFR decline was defined as an annual decline of ≤ 4 mL/min/1.73 m2. Clinical outcomes assessed included all-cause mortality, kidney outcomes (composite risk of kidney failure [progression to CKD stage 5] or > 50% eGFR decline, and kidney failure alone), cardiovascular events-including major adverse cardiovascular events (MACE; non-fatal myocardial infarction/stroke and cardiovascular death)-and all-cause hospitalization.

RESULTS

Across databases, rapid eGFR decline occurred in 13.7% of 804,237 eligible patients. Mean annual eGFR decline ranged between - 6.21 and - 6.86 mL/min/1.73 m2 in patients with rapid eGFR decline versus between - 0.11 and - 0.77 mL/min/1.73 m2 in patients with non-rapid eGFR decline. Rapid eGFR decline was associated with increased comorbidity burden and medication prescriptions. Across databases, the composite risk of kidney failure or > 50% decline in eGFR was significantly greater in patients with rapid versus non-rapid eGFR decline (P < 0.01); all-cause mortality, kidney failure alone, MACE, and all-cause hospitalization each significantly increased in two databases (P < 0.01-0.05).

CONCLUSION

Understanding patient factors associated with rapid eGFR decline in patients with CKD may help identify individuals who would benefit from proactive management to minimize the risk of adverse outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04034992.

Proteinuria and risk of ocular motor cranial nerve palsy: a nationwide population-based study

Understanding the association between dipstick-detected proteinuria and oculomotor cranial nerve palsy (CNP) could have significant implications for understanding the mechanism of CNP development and for developing preventive strategies against CNP development in patients with proteinuria. This study aimed to determine the relationship between dipstick-determined proteinuria and ocular motor CNP using National Sample Cohort (NSC) database from Korea's National Health Insurance Service (NHIS). A nationwide population-based cohort study was conducted using data from the NSC database of Korea's NHIS. These data were collected from 2009 to 2018. A one-year time lag was established to prevent a situation in which the causal link was inverted. Participants aged 20 years or more who were diagnosed with proteinuria in 2009 were included. Individuals with specific pre-existing CNP, missing data, and those who were newly diagnosed with CNP or who died within one year of being tested were excluded. The study population was classified into six groups according to the degree of proteinuria (negative, trace, or between 1 + and 4 +) based on the urine dipstick test. A Cox proportional hazard regression analysis was performed to determine the linkage between the degree of proteinuria and ocular motor CNP. A total of 5,807 (0.14% of subjects) with ocular motor CNP were assigned to the ocular motor CNP group and 4,047,205 subjects were assigned to the control group. After full adjustment of comorbidities, hazard ratios (HRs) for 1 + , 2 + , 3 + and 4 + proteinuria groups were 1.449 (95% confidence interval [CI] 1.244-1.687), 2.081 (1.707-2.538), 1.96 (1.322-2.904), and 3.011 (1.507-6.014), respectively, for developing ocular motor CNP compared to the proteinuria-negative group. In subgroup analysis, the HR of patients with proteinuria for the development of ocular motor CNP was higher in the younger age group (less than 40 years) (P = 0.0242) and the group with DM (P = 0.04). Our population-based cohort study demonstrated a significant association between proteinuria and the incidence of CNP, suggesting that urine protein level could be a new clinical marker for predicting the development of CNP.

Efficacy of Voclosporin in Proliferative Lupus Nephritis with High Levels of Proteinuria

BACKGROUND

In a phase 3 study of adults with active lupus nephritis, addition of voclosporin to mycophenolate mofetil (MMF) and low-dose glucocorticoids led to significant improvements in the proportion of participants achieving complete and partial renal response as well as sustained reduction in proteinuria. This analysis examined the efficacy and safety of voclosporin in a subgroup of the phase 3 study with proliferative lupus nephritis and high levels of proteinuria.

METHODS

Participants were randomized to oral voclosporin (23.7 mg twice daily) or placebo for 12 months; all participants received MMF and low-dose glucocorticoids. This analysis includes participants with class III or IV (±class V) lupus nephritis and baseline urine protein-creatinine ratio (UPCR) ≥3 g/g. Efficacy end points included complete renal response (UPCR ≤0.5 g/g with stable eGFR, low-dose glucocorticoids, and no rescue medication), partial renal response (≥50% reduction from baseline UPCR), and UPCR over time. Safety outcomes were also assessed.

RESULTS

A total of 148 participants were in the voclosporin ( n =76) and control ( n =72) arms. At 12 months, 34% and 11% of participants in the voclosporin and control arms, respectively, achieved a complete renal response (odds ratio, 4.43; 95% confidence interval [CI], 1.78 to >9.99; P = 0.001). A partial renal response was achieved by 65% of the voclosporin arm and 51% of the control arm at 12 months (odds ratio, 1.60; 95% CI, 0.8 to 3.20; P = 0.18). More voclosporin- than control-treated participants achieved UPCR ≤0.5 g/g (51% versus 26%), and voclosporin-treated participants met this end point significantly earlier (hazard ratio, 2.07; 95% CI, 1.19 to 3.60; P = 0.01). The incidence of adverse events was similar between the arms; mean eGFR values remained stable and within normal range in both arms.

CONCLUSIONS

Addition of voclosporin to MMF and low-dose glucocorticoids resulted in a significantly higher proportion of participants with proliferative lupus nephritis achieving complete and partial renal responses as well as earlier reductions in proteinuria, with no evidence of worsening kidney function.

Kidney function trajectories, associated factors, and outcomes in multiethnic Asian patients with type 2 diabetes

BACKGROUND

We examined the trajectory of estimated glomerular filtrate rate (eGFR), associated risk factors, and its relationship with end-stage kidney disease (ESKD) among a multiethnic patient population with type 2 diabetes in Singapore.

METHODS

A follow-up study included 62 080 individuals with type 2 diabetes aged ≥18 years in a multi-institutional SingHealth Diabetes Registry between 2013 and 2019. eGFR trajectories were analyzed using latent class linear mixed models. Factors associated with eGFR trajectories were evaluated using multinomial logistic regression. The association of eGFR trajectories with ESKD was assessed via competing risk models.

RESULTS

Trajectory of kidney function, determined by eGFR, was nonlinear. The trajectory pattern was classified as stable initially then gradual decline (75%), progressive decline (21.9%), and rapid decline (3.1%). Younger age, female sex, Malay ethnicity, lower-income housing type, current smoking, higher glycated hemoglobin, lower low-density lipoprotein, higher triglyceride, uncontrolled blood pressure, albuminuria, cardiovascular disease, hypertension, and higher eGFR levels each were associated with progressive or rapid decline. Compared with the trajectory of stable initially then gradual eGFR decline, progressive decline increased the hazard of ESKD by 6.14-fold (95% confidence interval [CI]: 4.96-7.61)) and rapid decline by 82.55 folds (95% CI: 55.90-121.89).

CONCLUSIONS

Three nonlinear trajectory classes of kidney function were identified among multiethnic individuals with type 2 diabetes in Singapore. About one in four individuals had a progressive or rapid decline in eGFR. Our results suggest that eGFR trajectories are correlated with multiple social and modifiable risk factors and inform the risk of ESKD.

Challenges of defining renal response in ANCA-associated vasculitis: call to action?

Avoiding end-stage kidney disease in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) has a high therapeutic priority. Although renal response is a crucial measure to capture clinically relevant changes, clinal trials have used various definitions and no well-studied key surrogate markers to predict renal outcome in AAV exist. Differences in clinical features and histopathologic and therapeutic approaches will influence the course of kidney function. Its assessment through traditional surrogates (i.e. serum creatinine, glomerular filtration rate, proteinuria, hematuria and disease activity scores) has limitations. Refinement of these markers and the incorporation of novel approaches such as the assessment of histopathological changes using cutting-edge molecular and machine learning mechanisms or new biomarkers could significantly improve prognostication. The timing is favourable since large datasets of trials conducted in AAV are available and provide a valuable resource to establish renal surrogate markers and, likely, aim to investigate optimized and tailored treatment approaches according to a renal response score. In this review we discuss important points missed in the assessment of kidney function in patients with AAV and point towards the importance of defining renal response and clinically important short- and long-term predictors of renal outcome.

Screening of Chronic Kidney Disease in Adults: A 10 years' Experience in North Indian City on World Kidney Day

Chronic kidney disease (CKD) is a complex disease that is asymptomatic in its early stages. Its delayed recognition may predispose patients to adverse outcomes. Early detection and management of kidney disease through screening programs is widely recommended. In the present study, we conducted a screening program at a hospital set up on World Kidney Day for 10 years to detect patients with CKD. The current study constituted 1324 apparently healthy adults, aged >18 years. Information on age, sex, height, weight, history of diabetes mellitus (DM) and hypertension (HTN), and familial history of kidney disease was recorded. Systolic and diastolic blood pressure, random blood sugar; urinalysis, and serum creatinine (Cr) levels were measured. The study outcome was the presence of CKD. Binary logistic regression analysis was applied to find the predictors of CKD. The median age of the study subjects was 40 years. CKD was found in 35.6% of subjects. Age, DM, HTN, and abnormal Cr levels were associated with increasing risk of CKD. The main objective of the present study was to identify the extent of risk relative to the co-factors of CKD and thereby target those who are potentially modifiable, like DM, to intervene at the earliest possible stage to treat the current disease condition and prevent the future health impairment.

Effects of receiving renal biopsy on the prognosis of chronic kidney disease patients with impaired renal function

BACKGROUND

Impaired renal function was not a recognized indication for renal biopsy. The effects of receiving renal biopsy on the renal functional prognosis for chronic kidney disease (CKD) patients with impaired renal function need to be explored.

METHODS

This study retrospectively enrolled 300 renal function impaired CKD patients in Renji Hospital from January 2015 to December 2017, 150 of them received percutaneous renal biopsy while the others did not. The endpoint was ≥ 50% estimated glomerular filtration rate (eGFR) decline from baseline or development of end-stage renal disease (ESRD). Kaplan-Meier analysis with log-rank test was performed to compare the renal survival probability between patients receiving renal biopsy or not. Univariate and multivariate analysis with Cox regression were conducted with predictors of poor renal outcomes in the study cohort.

RESULTS

The median follow-up period was 37.6 months. During the follow-up period, the eGFR of the biopsy group increased from 52.2 ± 14.4 to 67.4 ± 37.8 ml/min/1.73 m², but decreased from 55.3 ± 17.1 to 29.8 ± 19.1 ml/min/1.73 m² in the non-biopsy group. Patients who received renal biopsy had significantly higher renal survival probability (P < 0.001). Cox regression analysis revealed that 24-hour urine protein excretion (24 h UPE) more than 1 g/d was an independent predictor for poor renal outcomes in the non-biopsy group but not in the renal biopsy group (HR = 1.719, P = 0.040).

CONCLUSION

CKD patients with impaired renal function are recommended to receive renal biopsy to make pathological diagnoses, especially for those with the 24-hour urine protein excretion more than 1 g/d.

The effect of the Kasuya CKD network on prevention of the progression of chronic kidney disease: successful collaboration of a public health service, primary care physicians and nephrologists-community based cohort study

BACKGROUND

In 2012, we established a CKD network in collaboration with the public health service, primary care physicians, and nephrologists in the Kasuya area. The aim of this study was to clarify if our CKD network was effective in preventing CKD progression.

METHODS

1591 subjects, who had CKD in health checks in 2012 were included in this study. The slope of estimated glomerular filtration rate (eGFR) was compared before and after 2012. Parameters at the first health check visit before 2012, visit in 2012, and the last visit after 2012, were compared. Paired t test, analysis of variance for repeated measurements, and the Friedman test were used for the analysis.

RESULTS

Mean age was 65 years. There were 781 men and 810 women. Mean eGFR was 59 ml/min/1.73 m². The mean slope of eGFR before 2012 was -1.833 ml/min/1.73 m²/year and significantly reduced to - 0.297 after 2012. Low-density lipoprotein cholesterol showed a significant serial lowering. Uric acid was significantly elevated in 2012 compared to the first visit and had decreased by the last. The dipstick urinary protein significantly increased in 2012 compared to the first visit and decreased by the last. The number of current smokers showed a significant reduction over time. On the other hand, systolic blood pressure (SBP) and HbA1c significantly elevated at the last visit.

CONCLUSION

The Kasuya CKD network may be effective in preventing CKD progression.

Findings of Sodium-Glucose Cotransporter-2 Inhibitor Kidney Outcome Trials Applied to a Canadian Chronic Kidney Disease Population: A Retrospective Cohort Study

Background

The canagliflozin and renal endpoints in diabetes with established nephropathy clinical evaluation (CREDENCE) and dapagliflozin and prevention of adverse outcomes in chronic kidney disease (DAPA-CKD) trials have demonstrated significant kidney benefits with sodium-glucose cotransporter-2 (SGLT2) inhibitors. SGLT2 inhibitors are now standard of care for patients with diabetic kidney disease and have also been shown to be effective in those with albuminuric CKD with or without diabetes.

Objective

We sought to determine how many patients in nephrology care in British Columbia, Canada, would have been eligible for those trials, to compare rates of outcomes, and to estimate cost avoidance arising from widespread use of SGLT2 inhibitors in this cohort.

Study design

Retrospective cohort study.

Setting

British Columbia, Canada.

Participants

CKD patients followed in the Kidney Care Clinics in British Columbia.

Measurements

We compared the outcomes of kidney failure, sustained estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m², dialysis, transplant, death from any cause, and doubling of serum creatinine. We also compared the composite outcome of kidney failure and doubling of serum creatinine.

Methods

The cohort was derived using a provincial database by combining the inclusion criteria of CREDENCE and DAPA-CKD trials. We included adult patients aged ≥18 years, urine albumin to creatinine ratio (UACR) ≥20 mg/mmol, and eGFR between 25 and 90 mL/min/1.73 m², between April 1, 2014 and March 31, 2017. The primary outcome was compared with the outcomes experienced in the placebo arms of CREDENCE and DAPA-CKD. The composite outcome stratified by eGFR categories were compared in the British Columbia cohort and the CREDENCE trial. Cost avoidance was estimated based on the number needed to treat to prevent one instance of kidney failure.

Results

A total of 17.5% (3138/17 963) of patients were eligible, resulting in a cohort with a mean age of 69.7 years and 38% women. The eGFR slope of the British Columbia cohort was -4.21 ± 0.47 mL/min. The mean eGFR was 37.0 mL/min/1.73 m², median UACR was 55.3 mg/mmol, and use of renin-angiotensin-aldosterone system inhibitors was 56.6%. The British Columbia cohort experienced nearly double the outcomes of kidney failure, death from any cause, and doubling of serum creatinine than the placebo arms of CREDENCE and DAPA-CKD. When stratified by eGFR, the British Columbia cohort and the CREDENCE placebo arm had similar event rates for those with an eGFR <45 mL/min but there were still higher rates of outcome in the greater than 45 mL/min eGFR groups in the British Columbia cohort. Treating the British Columbia cohort with canagliflozin could lead to net cost avoidance of $2.31 million over 2.6 years.

Limitations

The database only captures those referred to the Kidney Care Clinics by nephrologists, which may lead to selection bias of higher risk patients in the British Columbia cohort. The cost avoidance analysis was a limited high-level analysis.

Conclusions

The British Columbia cohort represents a high-risk group in whom implementation of the use of SGLT2 inhibitors may well improve outcomes and reduce health care system costs.

Aging and hypertension in kidney function decline: A 10 year population-based study

Background

Aging is associated with a physiological decline in kidney function (KFD). In this study, we aimed to describe the impact of age on the rate of KFD and its interplay with risk factors for chronic kidney disease (CKD), considering mainly hypertension (HT), in the general population.

Materials and methods

Participants of European descent, aged 35-75, were recruited from a populational cohort in Lausanne, Switzerland. Participants with a 10 year follow-up were selected. KFD was defined as the difference in estimated glomerular filtration rate (eGFR) between baseline and follow-up, divided by the observation period. Multivariate linear regressions were used with KFD as the outcome and age as the main predictor. HT was tested as a modifying factor.

Results

We included 4,163 participants with mean age 52.2 ± 10.4, 44.7% men, 31.9% HT, and 5.0% diabetics. Mean baseline eGFR was 85.9 ± 14.6 ml/min/1.73 m². Mean KFD was -0.49 ± 1.08 ml/min/1.73 m² per year with 70% of participants decreasing their eGFR during follow-up. The relationship between age and KFD was non-linear and age was divided in tertiles. Old participants had faster rates of KFD as compared to young and middle-age participants (p < 0.001). A significant interaction was found between age and HT on KFD prediction (p < 0.001). In HT participants, KFD was significantly different across tertiles of age (p < 0.001). On contrary, KFD was not different across tertiles of age in non-HT participants.

Conclusion

A physiological KFD is present over time in the general population. Age contributes non-linearly to the rate of this decline with older subjects declining the fastest. The presence of HT is a major contributing factor in this setting as KFD worsened with age only in hypertensive participants. Thus, HT represents an important pathological factor aggravating the age-related physiological decline in eGFR in the general population.

Thyroid hormone increases oxygen metabolism causing intrarenal tissue hypoxia; a pathway to kidney disease

The proposed mechanisms for the development of nephropathy are many, complex and often overlapping. Although recent literature strongly supports a role of kidney hypoxia as an independent pathway to nephropathy, the evidence remains inconclusive since the role of hypoxia is difficult to differentiate from confounding factors such as hyperglycemia, hypertension and oxidative stress. By increasing kidney oxygen consumption using triiodothyronine (T₃) and, thus, avoiding these confounding factors, the aim of the present study was to investigate renal hypoxia per se as a causal pathway for the development of nephropathy. Healthy Sprague-Dawley rats were treated with T₃ (10 μg/kg/day) and the angiotensin II AT₁-receptor antagonist candesartan (1 mg/kg in drinking water) to eliminate effects of T₃-induced renin release; and compared to a candesartan treated control group. After 7 weeks of treatment in vivo kidney function, oxygen metabolism and mitochondrial function were evaluated. T₃ did not affect glomerular filtration rate or renal blood flow, but increased total kidney oxygen consumption resulting in cortical hypoxia. Nephropathy, demonstrated as albuminuria and tubulointerstitial fibrosis, developed in T₃-treated animals. Mitochondria uncoupling mediated by uncoupling protein 2 and the adenosine nucleotide transporter was demonstrated as a mechanism causing the increased kidney oxygen consumption. Importantly, blood glucose levels, mean arterial blood pressure and oxidative stress levels were not affected by T₃. In conclusion, the present study provides further evidence for increased kidney oxygen consumption causing intrarenal tissue hypoxia, as a causal pathway for development of nephropathy.

Vasohibin-1 has α-tubulin detyrosinating activity in glomerular podocytes

Podocytes are highly specialized epithelial cells in glomeruli, with a complex morphology composed of a cell body, primary processes, and foot processes, which maintain barrier function in glomerular filtration. The microtubule-based cytoskeleton is necessary for podocyte morphology. Microtubule structure and function can be affected by post-translational modification of tubulin, including detyrosination. Recent studies have shown that vasohibin-1 (VASH1), an antiangiogenic factor, has tubulin carboxypeptidase activity that causes detyrosination of α-tubulin. We aimed to examine the role of VASH1 in regulating α-tubulin detyrosination in podocytes and the potential involvement of VASH1 deficiency in renal morphology. In normal mouse kidneys, detyrosinated α-tubulin was mainly identified in glomeruli, especially in podocytes; meanwhile, in cultured immortalized podocytes, α-tubulin detyrosination was promoted with cell differentiation. Notably, α-tubulin detyrosination in glomeruli was diminished in Vash1 homozygous knockout (Vash1-/-) mice, and knockdown of VASH1 in cultured podocytes prevented α-tubulin detyrosination. Although VASH1 deficiency-induced downregulation of detyrosination caused no remarkable glomerular lesions, urinary albuminuria excretion and glomerular volume were significantly higher in Vash1-/- mice than in wild-type mice. Furthermore, decreased glomerular nephrin expression and narrower slit diaphragms width were observed in Vash1-/- mice. Taken together, we demonstrated that α-tubulin detyrosination in podocytes was mainly regulated by VASH1 and that VASH1 deficiency-mediated decreases in α-tubulin detyrosination led to minor alterations in podocyte morphology and predisposition to albuminuria. VASH1 expression and α-tubulin detyrosination may be novel targets for maintaining glomerular filtration barrier integrity.

Sex-Based Differences in Risk Factors and Complications of Chronic Kidney Disease

Globally, females are ∼30% more likely to have pre-dialysis chronic kidney disease (CKD) than males for reasons that are not fully understood. CKD is associated with numerous adverse health outcomes which makes understanding and working to eradicating sex based disparities in CKD prevalence essential. This review maps both what is known, and what is unknown, about the way sex and gender impacts (1) the epidemiology and risk factors for CKD including age, diabetes, hypertension, obesity, smoking, and cerebrovascular disease, and (2) the complications from CKD including kidney disease progression, cardiovascular disease, CKD mineral and bone disorders, anaemia, quality-of-life, cancer and mortality. This mapping can be used to guide future research.

Effect of Normalizing eGFR to Standard Body Surface Area on Rates of Obesity-Related Hyperfiltration among Diverse Female Adolescents

INTRODUCTION

Obesity is more prevalent among African American individuals, increasing the risk for cardiorenal morbidity. We explored interactions between race, BMI, and the risk of hyperfiltration associated with obesity-related glomerulopathy (ORG).

METHODS

We created a cohort of female adolescents from electronic health records. Glomerular filtration rate (GFR) was estimated in two ways: (A) using standard age recommended formulae and (B) absolute eGFR - adjusted to individual body surface area (BSA). Multivariate logistic regression was used to analyze the contribution of risk factors for ORG-associated hyperfiltration defined as 135 mL/min/1.73 m2 or 135 mL/min, according to BMI group. Pearson's coefficient was used to assess correlation with creatinine clearance (CrCl).

RESULTS

The final cohort included 7,315 African American and 15,102 non-African American adolescent females, with CrCl available for internal validation in 207 non-African American and 107 African American individuals. Compared with non-African American ethnicity, African American ethnicity was independently associated with a lower risk of hyperfiltration with standard eGFR calculations (odds ratio [OR] = 0.57, 95% confidence intervals [CIs] 0.45-0.71), associations were enhanced for absolute eGFR (OR = 0.81, 95% CI 0.69-0.95). Absolute eGFR values agreed better with CrCl (r = 0.63), compared to standard indexed eGFR formulae. Proportions classified as hyperfiltration changed with standard versus absolute eGFR; they were similar across BMI groups with the first and reflected obesity with the later.

CONCLUSION

Adjusting to individual BSA improves estimation of GFR and identification of obesity-related hyperfiltration. More accurate and earlier ascertainment of obesity-related hyperfiltration may have important consequences for preservation of kidney function.

Changes in Renal Function in Patients with Recurrence of Atrial Arrhythmia after an Initial Catheter Ablation

BACKGROUND

Impaired renal function and atrial fibrillation (AF) can form a vicious cycle. Although there have been reports on improved renal function in patients who undergo successful AF ablation, renal function in patients with recurrence of AF has not been studied separately. We explored the changes in renal function in recurrent AF patients after catheter ablation with mild renal dysfunction and the influencing factors.

METHODS

We retrospectively recruited nonvalvular AF (NVAF) patients with mildly impaired renal function admitted for catheter ablation and readmitted due to recurrence of AF. The estimated glomerular filtration rate (eGFR) was calculated before the index procedure and during readmission. △eGFR was defined as the difference between eGFR _readmission and eGFR _baseline. The same calculation applied for △CHA₂DS₂-VASc score. The primary endpoint was improved renal function (△eGFR >0) after AF catheter ablation in patients with atrial arrhythmia recurrence.

RESULTS

A total of 132 NVAF patients were included in this study. The mean eGFR at readmission was significantly increased compared with the eGFR at baseline before the index ablation procedure (81.5 ± 1.1 vs. 78.0 ± 0.7 ml/min/1.73 m², P < 0.001). The multivariable Cox regression analysis showed that a lower △CHA₂DS₂-VASc score (HR: 0.42, P=0.003) and paroxysmal recurrent atrial arrhythmia (HR: 2.97, P=0.001) were associated with better renal function.

CONCLUSION

In NVAF patients with mildly impaired renal function, even those with recurrence after the initial catheter ablation, we observed improvements in renal function, which was associated with a lower △CHA₂DS₂-VASc score and paroxysmal recurrent arrhythmia.

Albuminuria predicts worsening renal function after transcatheter aortic valve replacement

BACKGROUND

The impact of albuminuria on worsening renal function (WRF) and clinical outcomes after transcatheter aortic valve replacement (TAVR) is unknown.

METHODS

Overall, 142 patients who underwent TAVR for severe aortic stenosis were divided into two groups based on the preoperative urinary albumin-to-creatinine ratio (ACR): high (ACR ≥30 mg/g) and low (ACR <30 mg/g). The incidence of WRF (an absolute increase in serum creatinine level of ≥0.3 mg/dL or ≥1.5-fold from baseline or dialysis initiation) at 6 months after TAVR and the incidence of all-cause death and heart failure readmission during follow-up were investigated.

RESULTS

Half of the examined patients [n=71/142 (50.0%)] had a high ACR. Patients with a high ACR more frequently had WRF at 6 months than those with a low ACR (17.6% vs. 2.9%, p=0.004). Multivariate analysis showed a high ACR was independently associated with WRF (odds ratio, 7.76; 95% confidence interval, 1.62-37.30; p=0.01), whereas baseline estimated glomerular filtration rate <60 mL/min/1.73m² was not (odds ratio, 0.34; 95% confidence interval, 0.08-1.50; p=0.15). Patients with a high ACR had a higher risk of composite outcomes of all-cause death and heart failure readmission (p=0.002).

CONCLUSIONS

Preoperative albuminuria (ACR ≥30 mg/g) was independently associated with WRF at 6 months after TAVR. Furthermore, patients with an ACR ≥30 mg/g had higher risks of all-cause death and heart failure readmission than those with an ACR <30 mg/g.

Proteinuria and venous thromboembolism in pregnancy: a population-based cohort study

Background

Pregnancy-associated venous thromboembolism (VTE) is associated with high morbidity and mortality. Identification of risk factors of VTE may lead to improved maternal and foetal outcomes. Proteinuria confers a pro-thrombotic state, however, its association with VTE in pregnancy remains unknown. We set out to assess the association of proteinuria and VTE during pregnancy.

Methods

We conducted a population-based, retrospective cohort study of all pregnant women (≥16 years of age) with a proteinuria measure within 20 weeks of conception (n = 306 244; mean age 29.8 years) from Ontario, Canada. Proteinuria was defined by any of the following: urine albumin:creatinine ratio ≥3 mg/mmol, urine protein:creatinine ratio ≥5 mg/mmol or urine dipstick proteinuria ≥1. The main outcome measure was a diagnosis of VTE up to 24-weeks post-partum.

Results

A positive proteinuria measurement occurred in 8508 (2.78%) women and was more common with a history of kidney disease, gestational or non-gestational diabetes mellitus and hypertension. VTE events occurred in 625 (0.20%) individuals, with a higher risk among women with positive proteinuria [32 events (0.38%)] compared with women without proteinuria [593 events (0.20%); inverse probability-weighted risk ratio 1.79 (95% confidence interval 1.25-2.57)]. The association was consistent using a more specific VTE definition, in the post-partum period, in high-risk subgroups (hypertension or diabetes) and when the sample was restricted to women with preserved kidney function.

Conclusions

The presence of proteinuria in the first 20 weeks of pregnancy is associated with a significantly higher risk of VTE.

Association between thyroid-stimulating hormone (TSH) and proteinuria in relation to thyroid cyst in a euthyroid general population

Background

High normal levels of thyroid-stimulating hormone (TSH) have been reported to be associated with chronic kidney disease (CKD) among euthyroid individuals. However, there has been only limited research on the association between TSH and proteinuria, a major risk factor for the progression of renal disease.

Methods

A cross-sectional study of 1595 euthyroid individuals was conducted. All participants were within the normal range for free triiodothyronine (T3), free thyroxine (T4), and TSH. Analyses were stratified by thyroid cyst status to test the hypothesis that the absence of thyroid cysts, an indicator of latent thyroid damage, is associated with declining ability to synthesis thyroid hormone.

Results

For participants with thyroid cysts, a significant inverse association between TSH and proteinuria was observed (adjusted odds ratio (95% confidence intervals) of log-transformed TSH for proteinuria 0.40 (0.18, 0.89)). In participants without thyroid cysts, a significant positive association between those two factors was observed (2.06 (1.09, 3.90)).

Conclusions

Among euthyroid individuals in the general population, being in the normal range of TSH was found to have an ambivalent association with proteinuria. Thyroid cyst status could be an effect modifier for those associations.

Associations Between Kidney Function, Proteinuria, and the Risk of Kidney Cancer: A Nationwide Cohort Study Involving 10 Million Participants

Chronic kidney disease in its later stages is associated with increased risk of kidney cancer. We investigated whether chronic kidney disease at milder stages is associated with increased kidney cancer risk, using a retrospectively selected cohort of 9,809,317 adults in the Republic of Korea who participated in a nationwide health screening (2009-2016). We examined the impact of estimated glomerular filtration rate (eGFR), dipstick proteinuria, and interactive associations between the 2 factors on the risk of incident kidney cancer. During a median follow-up period of 7.3 years, 10,634 kidney cancers were identified. After adjustment for multiple confounders, participants with a reduced eGFR had an increased risk of kidney cancer (for eGFR <30 mL/minute/1.73 m2, adjusted hazard ratio = 1.18 (95% confidence interval: 1.01, 1.39); for eGFR 30-59 mL/minute/1.73 m2, adjusted hazard ratio = 1.22 (95% confidence interval: 1.14, 1.31)) compared with those with an eGFR of 60-89 mL/minute/1.73 m2. A dose-response relationship between the severity of proteinuria and incident kidney cancer was observed. Analyses of joint effects of eGFR and dipstick proteinuria showed that with the presence of proteinuria, kidney cancer incidence was markedly increased along with decreasing eGFR. Reduced eGFR and proteinuria are significantly associated with subsequent risk of kidney cancer, possibly in a synergistic manner.

Metabolic associated fatty liver disease is a risk factor for chronic kidney disease

Background and Aims

To clarify the relationship between metabolic dysfunction‐associated fatty liver disease (MAFLD) and chronic kidney disease (CKD).

Methods

The participants were divided into four groups by the presence or absence of fatty liver disease (FLD) and metabolic dysfunction (MD). MAFLD was defined as having both FLD and MD, whereas CKD was defined as having an estimated glomerular filtration rate of <60 mL/min/1.73 m² and/or proteinuria.

Results

In this cross‐sectional study of 27,371 participants, the proportions of those in the non‐FLD without MD, non‐FLD with MD, FLD without MD, and MAFLD groups were 48.7, 28.2, 2.3, and 20.8%, respectively. Compared with non‐FLD without MD, MAFLD was associated with the risk of CKD (adjusted odds ratio 1.83 [1.66–2.01], P < 0.001), whereas FLD without MD was not (1.02 [0.79–1.33], P = 0.868). Moreover, compared with FLD without MD, MAFLD was associated with the risk of CKD (1.19 [1.09–1.31], P < 0.001). In this retrospective cohort study, 16,938 of 27,371 participants underwent a median 4.6 (2.0–8.1) years follow‐up, and incident data of non‐FLD without MD, non‐FLD with MD, FLD without MD, and MAFLD were 21.0, 31.1, 26.1, and 31.1 cases per 1,000 person‐years, respectively. Compared with the non‐FLD without MD, MAFLD was associated with the risk of incident CKD (adjusted hazard ratio 1.24 [1.14–1.36], P < 0.001), whereas FLD without MD was not (1.11 [0.85–1.41], P = 0.433).

Conclusions

MAFLD was associated with a risk of CKD, whereas FLD without MD was not a risk for CKD.

The RNA binding protein hnRNPK protects against adriamycin-induced podocyte injury

Background

Podocytes maintain the integrity of the glomerular filtration barrier and serve as the final barrier to protein loss. Podocyte injury may induce severe apoptosis, which can result in serious kidney damage and disease. Therefore, it is necessary to explore how podocyte injury can be prevented and to thereby discover a feasible therapy for kidney disease. However, the mechanism of podocyte injury is still unclear.

Methods

The mRNA and protein expression levels of synaptopodin and nephrin in MPC5 podocytes with adriamycin (ADR)-induced injury were detected by quantitative real-time PCR and western blot. The expression levels of heterogeneous nucleotide protein K (hnRNPK), caspase-3, Bax, and Bcl-2 protein in cells and tissues were measured using western blot. Proliferation were measured in treated MPC5 podocytes by Cell Counting Kit-8 (CCK-8) assay, EdU assay, and apoptosis was measured by Hoechst 32258 staining. Mitochondrial membrane potential disruption, lactate dehydrogenase (LDH) leakage, and reactive oxygen species (ROS) generation were measured using JC-1 staining, an LDH reagent kit, and a ROS detection kit. Hematoxylin and eosin (HE) staining was used to observe histological changes in mouse tissues.

Results

Synaptopodin and nephrin were downregulated in ADR-treated podocytes. Overexpression of hnRNPK ameliorated the inhibitive effect of ADR treatment on podocyte proliferation and reduced its promotion of podocyte apoptosis. LDH leakage and ROS generation were increased in ADR-treated podocytes, but were reduced by hnRNPK treatment.

Conclusions

ADR-induced podocyte injury is ameliorated by hnRNPK both in vivo and in vitro. This observation provides a basis for a feasible therapy to prevent podocyte injury and subsequent kidney disease.

Evidence-Based Decision Making 6: Administrative Databases as Secondary Data Source for Epidemiologic and Health Service Research

Health-care systems require reliable information on which to base health-care planning and make decisions, as well as to evaluate their policy impact. Administrative data, predominantly captured for non-research purposes, provide important information about health services use, expenditures, and clinical outcomes and may be used to assess quality of care. With increased digitalization and accessibility of administrative databases, this data is more readily available for health service research purposes, aiding evidence-based decision making. This chapter discusses the utility of administrative data for population-based studies of health and health care.

Healthy lifestyle reduces incidence of trace/positive proteinuria and rapid kidney function decline after 2 years: from the Japan Ningen Dock study

BACKGROUND

Lifestyle modification is recommended for subjects with trace proteinuria during health checkups. However, whether overall healthy lifestyle reduces the incidence of trace/positive proteinuria or rapid decline in estimated glomerular filtration rate (eGFR) is not clarified.

METHODS

A total of 451 534 people (277 494 men and 174 040 women) ages 20-79 years with negative proteinuria were included. The number of three healthy lifestyle factors (LFs) was assessed: noncurrent smoking, healthy eating habits (late dinner, snacking and skipping breakfast <3 times/week) and body mass index <25. The incidence of trace (±) and positive (≥1+) proteinuria by the dipstick method and eGFR decline ≥20% over 2 years were compared with the number of healthy LFs.

RESULTS

The incidence of trace/positive proteinuria and rapid eGFR decline decreased with an increasing number of healthy LFs as follows: odds ratios (ORs) for trace proteinuria, 0.91 [95% confidence interval (CI) 0.86-0.96], 0.82 (0.78-0.87) and 0.72 (0.68-0.77); ORs for positive proteinuria, 0.76 (95% CI 0.67-0.86), 0.56 (0.50-0.63) and 0.46 (0.40-0.53); and ORs for an eGFR decline ≥20%, 0.93 (95% CI 0.82-1.05), 0.90 (0.79-1.02) and 0.81 (0.70-0.93) for those with one, two and three healthy LFs compared with those with none of the three healthy LFs, respectively. Overall, subjects with a healthy lifestyle showed 28, 54 and 19% reduced risk of developing trace proteinuria, positive proteinuria and eGFR decline ≥20%, respectively, compared with those with an unhealthy lifestyle after 2 years. This association was similarly observed even among subjects without hypertension (HT) or diabetes mellitus (DM).

CONCLUSIONS

Subjects with an overall healthy lifestyle showed a lower incidence of trace/positive proteinuria by dipstick test and rapid eGFR decline over 2 years in a nationwide general population. Thus lifestyle modification should be recommended for subjects with trace proteinuria during health checkups, even for subjects without HT or DM.

Ex Vivo Expanded 3D Human Kidney Spheres Engraft Long Term and Repair Chronic Renal Injury in Mice

End-stage renal disease is a worldwide epidemic requiring renal replacement therapy. Harvesting tissue from failing kidneys and autotransplantation of tissue progenitors could theoretically delay the need for dialysis. Here we use healthy and end-stage human adult kidneys to robustly expand proliferative kidney epithelial cells and establish 3D kidney epithelial cultures termed "nephrospheres." Formation of nephrospheres reestablishes renal identity and function in primary cultures. Transplantation into NOD/SCID mice shows that nephrospheres restore self-organogenetic properties lost in monolayer cultures, allowing long-term engraftment as tubular structures, potentially adding nephron segments and demonstrating self-organization as critical to survival. Furthermore, long-term tubular engraftment of nephrospheres is functionally beneficial in murine models of chronic kidney disease. Remarkably, nephrospheres inhibit pro-fibrotic collagen production in cultured fibroblasts via paracrine modulation, while transplanted nephrospheres induce transcriptional signatures of proliferation and release from quiescence, suggesting re-activation of endogenous repair. These data support the use of human nephrospheres for renal cell therapy.

Proteinuria Is Associated with the Development of Crohn's Disease: A Nationwide Population-Based Study

BACKGROUND AND AIMS

The impact of proteinuria and its severity on the incidence of inflammatory bowel disease (IBD) has not yet been studied. We aimed to determine the association between proteinuria measured by urine dipstick tests and the development of IBD.

METHODS

This nationwide population-based study was conducted using the Korean National Health Insurance Service (NHIS) database. A total of 9,917,400 people aged 20 years or older who had undergone a national health examination conducted by the NHIS in 2009 were followed up until 2017. The study population was classified into four groups-negative, trace, 1+, and ≥ 2+-according to the degree of proteinuria measured by the urine dipstick test. The primary endpoint was newly diagnosed IBD, Crohn's disease (CD), or ulcerative colitis (UC) during the follow-up period.

RESULTS

Compared with the dipstick-negative group, the incidence of CD significantly increased according to the degree of proteinuria (adjusted hazard ratio [aHR] with 95% confidence interval [CI], 1.01 [0.703-1.451], 1.515 [1.058-2.162], and 2.053 [1.301-3.24] in the trace, 1+, and ≥ 2+ dipstick groups, respectively; p for trend 0.007). However, there was no significant difference in the incidence of UC according to the degree of proteinuria (aHR with 95% CI, 1.12 [0.949-1.323], 0.947 [0.764-1.174], and 1.009 [0.741-1.373] in the trace, 1+, and ≥ 2+ dipstick groups, respectively; p for trend 0.722). In the subgroup analysis, dipstick-positive proteinuria independently increased the incidence of CD regardless of the subgroup. However, dipstick-positive proteinuria was associated with the risk of UC in those with diabetes mellitus and not in those without diabetes mellitus (aHR, 1.527 vs. 0.846; interaction p-value 0.004). The risk of CD was increased or decreased according to proteinuria changes but not associated with the risk of UC.

CONCLUSION

Proteinuria, measured by the dipstick test, is strongly associated with the development of CD.

Chronic kidney disease detection, staging and treatment in cardiovascular disease prevention

Globally, nearly 10% of the population has chronic kidney disease (CKD), defined as a glomerular filtration rate less than 60 mL/min/1.73 m² and/or a urinary albumin to creatinine ratio greater than 30 mg/g (3 mg/mmol). Persons with CKD have a substantially high risk of cardiovascular disease. Indeed, most persons with CKD are far more likely to develop a cardiovascular event than to progress to end-stage kidney disease. Although early detection and staging of CKD could help prevent its cardiovascular consequences, current rates of testing for CKD are very low, even among high-risk populations such as persons with diabetes, hypertension and cardiovascular disease. In this review, we first describe the need to test for both estimated glomerular filtration rate and albuminuria among persons at high risk of CKD in order to properly stage CKD and enhance cardiovascular risk stratification. We then discuss how detection and staging for CKD could help prioritise patients at high risk of atherosclerotic cardiovascular disease and heart failure who could derive the largest benefit from cardiovascular preventive interventions. In addition, we discuss the central role of CKD detection and staging in the initiation of cardiorenal preventive therapies, such as the sodium-glucose cotransporter 2 inhibitors, which have shown overwhelming evidence of cardiorenal protection. We conclude by discussing strategies to overcome historical barriers to CKD detection and treatment.

Semaphorin3A-Inhibitor Ameliorates Doxorubicin-Induced Podocyte Injury

Podocyte injury is an independent risk factor for the progression of renal diseases. Semaphorin3A (SEMA3A), expressed in podocytes and tubular cells in the mammalian adult kidneys, has been reported to regulate diverse biological functions and be associated with renal diseases. Here, we investigated pathological roles of SEMA3A signaling on podocyte injury using a doxorubicin (Dox)-induced mouse model and examined the therapeutic effect of SEMA3A-inhibitor (SEMA3A-I). We demonstrated that Dox caused massive albuminuria and podocyte apoptosis as well as an increase of SEMA3A expression in podocytes, all of which were ameliorated with SEMA3A-I treatment. In addition, c-Jun N-terminal kinase (JNK), known as a downstream of SEMA3A signaling, was activated in Dox-injected mouse podocytes while SEMA3A-I treatment partially blocked the activation. In vitro, SEMA3A-I protected against Dox-induced podocyte apoptosis and recombinant SEMA3A caused podocyte apoptosis with activation of JNK signaling. JNK inhibitor, SP600125, attenuated SEMA3A-induced podocyte apoptosis, indicating that the JNK pathway would be involved in SEMA3A-induced podocyte apoptosis. Furthermore, the analysis of human data revealed a positive correlation between levels of urinary SEMA3A and protein, suggesting that SEMA3A is associated with podocyte injury. In conclusion, SEMA3A has essential roles in podocyte injury and it would be the therapeutic target for protecting from podocyte injury.

Changes in kidney function follow living donor nephrectomy

Better understanding of kidney function after living donor nephrectomy and how it differs by donor characteristics can inform patient selection, counselling, and follow-up care. To evaluate this, we conducted a retrospective matched cohort study of living kidney donors in Alberta, Canada between 2002-2016, using linked healthcare administrative databases. We matched 604 donors to 2,414 healthy non-donors from the general population based on age, sex, year of cohort entry, urban residence and the estimated glomerular filtration rate (eGFR) before cohort entry (nephrectomy date for donors and randomly assigned date for non-donors). The primary outcome was the rate of eGFR change over time (median follow-up seven years; maximum 15 years). The median age of the cohort was 43 years, 64% women, and the baseline (pre-donation) eGFR was 100 mL/min/1.73 m². Overall, from six weeks onwards, the eGFR increased by +0.35 mL/min/1.73 m² per year (95% confidence interval +0.21 to +0.48) in donors and significantly decreased by -0.85 mL/min/1.73 m² per year (-0.94 to -0.75) in the matched healthy non-donors. The change in eGFR between six weeks to two years, two to five years, and over five years among donors was +1.06, +0.64, and -0.06 mL/min/1.73 m² per year, respectively. In contrast to the steady age-related decline in kidney function in non-donors, post-donation kidney function on average initially increased by 1 mL/min/1.73 m² per year attributable to glomerular hyperfiltration, which began to plateau by five years post-donation. Thus, the average change in eGFR over time is significantly different between donors and non-donors.

Housing Insecurity and Risk of Adverse Kidney Outcomes

Background

Housing insecurity is characterized by high housing costs or unsafe living conditions that prevent self-care and threaten independence. We examined the relationship of housing insecurity and risk of kidney disease.

Methods

We used longitudinal data from the Healthy Aging in Neighborhoods of Diversity across the Life Span study (Baltimore, MD). We used multivariable regression to quantify associations between housing insecurity and rapid kidney function decline (loss of >5 ml/min per 1.73 m² of eGFR per year) and, among those without kidney disease at baseline, incident reduced kidney function (eGFR <60 ml/min per 1.73 m²) and incident albuminuria (urine albumin-creatinine ratio [ACR] ≥30 mg/g).

Results

Among 1262 participants, mean age was 52 years, 40% were male and 57% were black. A total of 405 (32%) reported housing insecurity. After a median of 3.5 years of follow-up, rapid kidney function decline, incident reduced kidney function, and incident albuminuria occurred in 199 (16%), 64 (5%), and 74 (7%) participants, respectively. Housing insecurity was associated with increased odds of incident albuminuria (unadjusted OR, 2.04; 95% CI, 1.29 to 3.29; adjusted OR, 3.23; 95% CI, 1.90 to 5.50) but not rapid kidney function decline or incident reduced kidney function.

Conclusions

In this urban population, housing insecurity was associated with increased risk of subsequent albuminuria. Increased recognition of housing insecurity as a social determinant of kidney disease is needed, and risk-reduction efforts that specifically target populations experiencing housing insecurity should be considered.

Factors Associated with a Large Decline in Renal Function or Progression to Renal Insufficiency in Hospitalized Atrial Fibrillation Patients with Early-Stage CKD

Clinicians must consider renal function when administering anticoagulants for atrial fibrillation (AF). Determination of risk factors for renal function decline may enable identification of patients who require closer monitoring. We investigated the characteristics associated with renal function decline in patients with AF. The study cohort consisted of 631 AF patients who had at least one readmission during the follow-up period and stages 1-3 chronic kidney disease (CKD). The primary outcome measure was large renal function decline (≥30% decrease from baseline estimated glomerular filtration rate [eGFR]). The secondary outcome measure was a final eGFR < 60 mL/minute/1.73 m² for those with a baseline eGFR above this level. The mean eGFR was 74.4 ± 18.5 mL/minute/1.73 m², and the mean follow-up time was 30.2 ± 13.2 months. The primary outcome occurred in 155 patients (24.6%) and was associated with congestive heart failure (CHF), proteinuria, type of AF, and left atrial diameter (LAD) ≥ 45 mm. Among 478 patients with a baseline eGFR ≥ 60 mL/minute/1.73 m², 137 (28.7%) progressed to renal failure (eGFR < 60 mL/minute/1.73 m²). A decreasing eGFR was associated with age ≥ 75 years, CHF, lower baseline eGFR, and LAD ≥ 45 mm. CHF, proteinuria, type of AF, and LAD ≥ 45 mm were associated with eGFR decline ≥ 30% in AF patients with CKD stages 1-3. Advanced age, CHF, lower baseline eGFR, and LAD ≥ 45 mm were associated with progression to renal insufficiency. These results should be considered when identifying patients who require more frequent monitoring of eGFR.

The epidemiology of chronic kidney disease (CKD) in rural East Africa: A population-based study

Background

Chronic kidney disease (CKD) may be common among individuals living in sub-Saharan Africa due to the confluence of CKD risk factors and genetic predisposition.

Methods

We ascertained the prevalence of CKD and its risk factors among a sample of 3,686 participants of a population-based HIV trial in rural Uganda and Kenya. Prevalent CKD was defined as a serum creatinine-based estimated glomerular filtration rate <60 mL/min/1.73m² or proteinuria (urine dipstick ≥1+). We used inverse-weighting to estimate the population prevalence of CKD, and multivariable log-link Poisson models to assess the associations of potential risk factors with CKD.

Results

The estimated CKD prevalence was 6.8% (95% CI 5.7–8.1%) overall and varied by region, being 12.5% (10.1–15.4%) in eastern Uganda, 3.9% (2.2–6.8%) in southwestern Uganda and 3.7% (2.7–5.1%) in western Kenya. Risk factors associated with greater CKD prevalence included age ≥60 years (adjusted prevalence ratio [aPR] 3.5 [95% CI 1.9–6.5] compared with age 18–29 years), HIV infection (aPR 1.6 [1.1–2.2]), and residence in eastern Uganda (aPR 3.9 [2.6–5.9]). However, two-thirds of individuals with CKD did not have HIV, diabetes, or hypertension as risk factors. Furthermore, we noted many individuals who did not have proteinuria had dipstick positive leukocyturia or hematuria.

Conclusion

The prevalence of CKD is appreciable in rural East Africa and there are considerable regional differences. Conventional risk factors appear to only explain a minority of cases, and leukocyturia and hematuria were common, highlighting the need for further research into understanding the nature of CKD in sub-Saharan Africa.

Chronic Kidney Disease among Middle-Aged and Elderly Population: A cross-sectional screening in a Hospital Camp in Varanasi, India

Chronic kidney disease (CKD) is no longer considered just a health burden, but a major health priority owing to its high treatment costs and poor outcome. The lack of community-based screening programs has led to the detection of CKD patients at advanced stages. This study aims to estimate the prevalence of CKD and patterns of known risk factors among the general population (middle-aged and elderly) attending a screening camp in a community-based setting. The study participants constituted a part of the general population of Varanasi (aged ≥45 years) who volunteered in a screening camp that was organized as part of the World Kidney Day Initiative at Opal Hospital. Information on age, sex, height, weight, smoking and drug history, history of diabetes, hypertension, and family history of kidney disease was extensively interrogated, while laboratory investigations such as urinalysis and serum creatinine levels were recorded. More than three-fifths of the participants were middle-aged adults (i.e., 45-64 years) and the remaining 34.8% were elderly population, i.e., ≥65 years. The overall prevalence of CKD in the 198 studied participants was 29.3%. Higher number of participants (40.6%) of elderly population had CKD (P = 0.011). The serum creatinine, albuminuria, and estimated glomerular filtration rate levels were strongly associated with CKD (P <0.05). Our study suggests that elderly individuals are at risk with higher serum creatinine levels and would benefit from early detection of CKD to prevent disease progression and associated morbidity and mortality.

Impact of gender and gender disparities in patients with kidney disease

PURPOSE OF REVIEW

Despite evidence of gender-specific differences in epidemiology and outcomes in all stages of chronic kidney disease (CKD), most studies ignore the issue of gender. This review addresses this knowledge gap by evaluating data on gender disparity in this population.

RECENT FINDINGS

Population-based studies indicate a higher prevalence of CKD in women; however, there are fewer women on renal replacement therapy than men. Men may progress to end-stage kidney disease more rapidly. Gender differences in rates of CKD progression may be influenced by potential antifibrotic and antiapoptotic effects of estrogen or proinflammatory deleterious effects of testosterone. Women are referred later for kidney replacement therapy and receive fewer arteriovenous fistulas than men receive, irrespective of race. Women are also less likely to receive kidney transplants as compared with men but are more likely to donate a kidney.

SUMMARY

Recommendations for medical management of CKD patients are currently made in a gender-blind manner, despite the fact that women have differing underlying physiology. Addressing gender differences and disparities is an important and overlooked area in the care of patients with kidney disease.

Sonic hedgehog connects podocyte injury to mesangial activation and glomerulosclerosis

Glomerular disease is characterized by proteinuria and glomerulosclerosis, two pathologic features caused by podocyte injury and mesangial cell activation, respectively. However, whether these two events are linked remains elusive. Here, we report that sonic hedgehog (Shh) is the mediator that connects podocyte damage to mesangial activation and glomerulosclerosis. Shh was induced in glomerular podocytes in various models of proteinuric chronic kidney diseases (CKD). However, mesangial cells in the glomeruli, but not podocytes, responded to hedgehog ligand. In vitro, Shh was induced in podocytes after injury and selectively promoted mesangial cell activation and proliferation. In a miniorgan culture of isolated glomeruli, Shh promoted mesangial activation but did not affect the integrity of podocytes. Podocyte-specific ablation of Shh in vivo exhibited no effect on proteinuria after adriamycin injection but hampered mesangial activation and glomerulosclerosis. Consistently, pharmacologic blockade of Shh signaling decoupled proteinuria from glomerulosclerosis. In humans, Shh was upregulated in glomerular podocytes in patients with CKD and its circulating level was associated with glomerulosclerosis but not proteinuria. These studies demonstrate that Shh mechanistically links podocyte injury to mesangial activation in the pathogenesis of glomerular diseases. Our findings also illustrate a crucial role for podocyte-mesangial communication in connecting proteinuria to glomerulosclerosis.

Geriatric Nutritional Risk Index Is Associated with Unique Health Conditions and Clinical Outcomes in Chronic Kidney Disease Patients

Malnutrition is prevalent in patients with chronic kidney disease (CKD). However, current nutrition screening tools are not specific to the CKD population. In the present study, we aimed to investigate whether the geriatric nutritional risk index (GNRI), a simple tool designed for assessing nutrition-related risks in the elderly population, is associated with unique aspects of CKD such as fluid status, residual renal function, proteinuria, and inflammation, and whether it predicts clinical outcomes. The GNRI was calculated by incorporating serum albumin and anthropometric measurements in 326 patients with nondialysis stage 3–5 CKD who were followed up from September 2011 to March 2017 for end-stage renal disease (ESRD) and the composite outcome of all-cause death and cardiovascular events. Patients were stratified into tertiles according to baseline GNRI levels. Patients in the lowest GNRI tertile were more likely to have significantly higher levels of overhydration, proteinuria, and serum inflammatory markers and tended to have lower lean body mass and estimated glomerular filtration rate when compared with patients in the middle and upper GNRI tertiles. In multivariate linear regression analyses, the GNRI was independently associated with overhydration, proteinuria, and interleukin-6. During a median follow-up of 4.9 years, 101 patients developed ESRD; 40 deaths, and 68 cardiovascular events occurred. Patients in the lowest GNRI tertile had significantly increased risks of ESRD (hazard ratio (HR): 3.15, 95% confidence interval (CI): 1.95–5.07, p < 0.001) and the composite outcome (HR: 1.79, 95% CI: 1.10–2.92, p = 0.019) in fully adjusted models (reference: middle and upper GNRI tertiles). The GNRI takes CKD-specific health conditions into account. In addition, CKD patients with lower GNRI scores had a significantly higher risk of adverse clinical outcomes. Our findings suggest that the GNRI is an appropriate tool for nutrition screening and a prognostic predictor among patients with nondialysis stage 3–5 CKD.

A review of renal GH/IGF1 family gene expression in chronic kidney diseases

Despite decades of study on the contribution of growth hormone (GH) to the development of kidney disease, there remains the question of the relative contribution of elevated levels of GH to kidney damage in humans, particularly in diabetic nephropathy occurring in type 1 patients. In this study, we reviewed several publicly available datasets to examine transcription of twelve genes associated with the GH/IGF1 axis in several types of human and rodent kidney diseases. Our analyses revealed downregulation of renal GHR and IGF1 gene expression in several different chronic human kidney diseases, including diabetic nephropathy, with general upregulation of IGFBP6 in the same tissues and diseases. These findings were generally supported by a review of studies in rodent models. In healthy and diseased human kidneys, increased GHR gene expression was associated with increases in glomerular filtration rate (GFR) and decreases in serum creatinine. IGFBP6 gene expression demonstrated the opposite clinical correlation. Our results suggest the kidney may exhibit GH insensitivity due to low GHR gene expression during most chronic kidney diseases.

Usefulness of ambulatory blood pressure monitoring in chronic kidney disease: The moroccan experience

Among patients with chronic kidney disease (CKD), hypertension (HTN) is very common and widely recognized to accelerate the progression of CKD and increase the risk for cardiovascular events. Accumulated data indicate that ambulatory blood pressure monitoring (ABPM) is better in detecting HTN than office blood pressure (BP) measurement. The goal of this study is to describe the ABPM characteristics in a group of CKD and hypertensive patients. A transversal study was conducted over a period of six months, to evaluate the ABPM patterns among a group of hypertensive patients with CKD (Group 1) and compared the data with a control group (Group 2). ABPM was performed with measurement rate every 15 min during daytime and 30 min at night. Nondipping BP patterns were defined as the absence of fall in nocturnal systolic and diastolic BP >10% of daytime values. Masked HTN was defined as controlled office BP (<140/90 mm Hg) with an elevated overall average BP by 24-h ABPM (>125/75 mm Hg), and white-coat HTN was defined as association of elevated BP readings (>140/90 mm Hg) in a clinical setting and normal 24-h average BP levels (<130/80 mm Hg). Fifty patients were included in each group. HTN was much longer in duration among hypertensive patients with CKD and frequently associated with obesity, dyslipidemia, and diabetes (64% vs. 39.60%). Positive proteinuria was present in 82% of CKD patients with HTN. CKD patients with HTN received more antihypertensive drugs than Group 2 patients. HTN was much more uncontrolled among CKD patients (60% vs. 24%), more serious with higher daytime and nighttime SBP, and loss of physiologic dipping during nighttime BP measurement (80%). Out-of-office BP monitoring by ABPM may improve the assessment and the successful management of HTN in patients with CKD. Standardized definitions for the diagnosis of masked and white-coat HTN would facilitate research.

Associated factors related to chronic kidney disease progression in elderly patients

Background

Chronic Kidney Disease (CKD) is a worldwide public health problem. The prevalence of CKD is rising especially in elderly, as consequence of population-ageing related to socioeconomic development and better life expectancy. There are scarce studies evaluating CKD progression and its associated factors in elderly patients.

Methods

This is a retrospective observational study including 340 patients (≥ 65 years old) CKD stages 3a–5 non-dialysis, incidents in an outpatient CKD clinic, followed by 2.1 years. CKD progression was assessed by the slope of eGFR calculated by CKD-EPI and BIS 1 equations. The patients were divided in progressor and non-progressor groups (eGFR slope < or ≥ 0 mL/min/1.73 m²/year, respectively).

Results

Kidney function declined in 193 (57%) patients. In this group, the progression rate was -2.83 (-5.1 / -1.1) mL /min /1.73 m² /year. Compared to non progressor, the progressor patients were younger [72 (69–78) vs. 76 (69–80) years; p = 0.02]; had higher proportion of diabetic nephropathy, higher serum phosphorus [3.8 (3.3–4.1) vs. 3.5 (3.9–4.1) mg/dL; p = 0.04] and proteinuria [0.10 (0–0.9 vs. 0 (0–0.3)] g/L; p = 0.007)] at the admission. In the logistic regression analysis adjusted for gender and eGFR, proteinuria was independently associated with CKD progression [OR (Odds Ratio) (1.83; 95% CI, 1.17–2.86; p < 0.01)].

Conclusion

CKD progression was observed in the majority of elderly CKD patients and proteinuria was the most important factor associated to the decline of kidney function in this population.

Association between Plasma Levels of Growth Differentiation Factor-15 and Renal Function in the Elderly: Korean Frailty and Aging Cohort Study

BACKGROUND/AIMS

Growth differentiation factor-15 (GDF-15) expression has been reported to increase in response to tissue damage and has recently emerged as a useful biomarker for various diseases. Although emerging evidence supports the clinicopathological value of GDF-15 in renal impairment, few studies have analyzed it in the elderly. Thus, we conducted a cross-sectional study to investigate the association of plasma GDF-15 with renal function and the presence of chronic kidney disease (CKD) in community-dwelling elderly.

MATERIALS

The present study was based on the baseline data of the Korean Frailty and Aging Cohort Study (KFACS), a nationwide cohort study that began in 2016. Of the 1,559 participants assessed in the first year, 443 with available plasma GDF-15 data were enrolled in this study. We investigated the association of plasma GDF-15 levels with clinical and biochemical parameters. The study population was divided into two groups according to renal function (CKD and non-CKD groups) to investigate whether GDF-15 can determine the presence of renal dysfunction in the elderly. Plasma GDF-15 was measured by enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

In a simple regression analysis, the levels of plasma GDF-15 were negatively correlated with estimated glomerular filtration rate (eGFR; r = -0.383, p < 0.001). In multiple linear regression analysis, GDF-15 levels were still significantly correlated with eGFR, even after adjusting for other parameters (r = -0.259, p < 0.001). Plasma GDF-15 levels were significantly higher in the elderly with CKD than in those without CKD (2,364.025 ± 1,052.23 ng/L and 1,451.23 ± 835.79 ng/L, respectively; p < 0.001). The optimal cut-off value of plasma GDF-15 for detecting the presence of CKD was 1,699.4 ng/L (76.5% sensitivity and 76.0% specificity), as determined by the receiver operating characteristic curve. The area under the curve was 0.793 ± 0.033 (95% CI 0.729-0.857, p < 0.001).

CONCLUSION

Plasma GDF-15 levels were negatively associated with eGFR and were significantly increased in the elderly with CKD. Our results suggested that plasma GDF-15 might be a useful marker for discriminating renal impairment in the elderly. Further large and prospective outcome studies of extended duration are needed.

Research-based versus clinical serum creatinine measurements and the association of acute kidney injury with subsequent kidney function: findings from the Chronic Renal Insufficiency Cohort study

Background

Observational studies relying on clinically obtained data have shown that acute kidney injury (AKI) is linked to accelerated chronic kidney disease (CKD) progression. However, prior reports lacked uniform collection of important confounders such as proteinuria and pre-AKI kidney function trajectory, and may be susceptible to ascertainment bias, as patients may be more likely to undergo kidney function testing after AKI.

Methods

We studied 444 adults with CKD who participated in the prospective Chronic Renal Insufficiency Cohort (CRIC) Study and were concurrent members of a large integrated healthcare delivery system. We estimated glomerular filtration rate (eGFR) trajectories using serum creatinine measurements from (i) the CRIC research protocol (yearly) and (ii) routine clinical care. We used linear mixed effects models to evaluate the associations of AKI with acute absolute change in eGFR and post-AKI eGFR slope, and explored whether these varied by source of creatinine results. Models were adjusted for demographic characteristics, diabetes status and albuminuria.

Results

During median follow-up of 8.5 years, mean rate of eGFR loss was −0.31 mL/min/1.73 m²/year overall, and 73 individuals experienced AKI (55% Stage 1). A significant interaction existed between AKI and source of serum creatinine for acute absolute change in eGFR level after discharge; in contrast, AKI was independently associated with a faster rate of eGFR decline (mean additional loss of −0.67 mL/min/1.73 m²/year), which was not impacted by source of serum creatinine.

Conclusions

AKI is independently associated with subsequent steeper eGFR decline regardless of the serum creatinine source used, but the strength of association is smaller than observed in prior studies after taking into account key confounders such as pre-AKI eGFR slope and albuminuria.

Reduced Kidney Function in Tenofovir Disoproxil Fumarate Based Regimen and Associated Factors: A Hospital Based Prospective Observational Study in Ethiopian Patients

Purpose

Tenofovir disoproxil fumarate (TDF), a drug broadly used in combination antiretroviral therapy, is associated with renal dysfunction but the prevalence varied from country to country and it is not known in Ethiopia. The objectives of this study were to assess the prevalence of renal dysfunction and risk factors associated with it and the mean change in estimated glomerular filtration rate in human immunodeficiency virus infected patients receiving TDF based antiretroviral regimen at Tikur Anbessa Specialized Hospital.

Method

It was a hospital based prospective cohort study. The study participants were treatment naïve HIV infected patients initiating TDF containing combination antiretroviral therapy or switched to it because of adverse events. Multivariable logistic analysis was used to identify variables which have significant association.

Result

A total of 63 study participants were studied, 16 (25.4%) of whom had fall in eGFR greater than 25% relative to baseline. Only age greater than 50 years, baseline CD4 count less than 200 cells/mm³, and baseline proteinuria were significantly associated with renal dysfunction in multivariable logistic regression. There was -8.4 ml/min/1.73m² mean change in estimated glomerular filtration rate relative to baseline at six months of study.

Conclusion

The renal dysfunction (defined as decline in eGFR greater than 25%) was found in a quarter of the study population. The long term impact and the clinical implication of it are not clear. Future prospective study is required with large sample size and long duration to ascertain the prevalence of decline greater than 25% in estimated glomerular filtration rate and its progression to chronic kidney disease.

Correlation Between Baseline GFR and Subsequent Change in GFR in Norwegian Adults Without Diabetes and in Pima Indians

RATIONALE & OBJECTIVE

An elevated glomerular filtration rate (GFR), or renal hyperfiltration, may predispose individuals to subsequent rapid GFR decline in diabetes, obesity, and metabolic syndrome. Although this hypothesis is supported by results of experimental studies, the importance of hyperfiltration at the population level remains controversial. We investigated whether higher baseline GFR predicts a steeper decline in GFR.

STUDY DESIGN

Longitudinal cohort studies.

SETTING & PARTICIPANTS

1,594 middle-aged Norwegians without diabetes (the Renal Iohexol Clearance Survey [RENIS]) and 319 Pima Indians (83% with type 2 diabetes).

PREDICTOR

Baseline measured GFR using exogenous clearance methods.

OUTCOMES

Change in measured GFR over time.

ANALYTICAL APPROACH

Linear mixed regression models fit to assess the correlation between the random intercept (reflecting baseline GFR) and random slope (change in GFR over time).

RESULTS

Mean baseline GFRs were 104.0 ± 20.1 (SD) and 149.4 ± 43.3 mL/min, and median follow-up durations were 5.6 (IQR, 5.2-6.0) and 9.1 (IQR, 4.0-15.0) years in the RENIS and Pima cohorts, respectively. Correlation between baseline GFR (random intercept) and slope of GFR decline was -0.31 (95% CI, -0.40 to -0.23) in the RENIS cohort and -0.41 (95% CI, -0.55 to -0.26) in the Pima cohort, adjusted for age, sex, height, and weight, suggesting that higher baseline GFRs were associated with steeper GFR decline rates.

LIMITATIONS

Different methods for measuring GFR in the 2 cohorts. Renal hyperfiltration may not reflect higher single-nephron GFR. GFR decline is assumed to be linear, which may not match the actual pattern; observed correlations may arise from natural variation.

CONCLUSIONS

Higher baseline GFR is associated with faster decline in GFR over time. If this relationship were causal, elevated GFR would represent a potentially modifiable risk factor for medium- to long-term GFR decline.

The burden of hypertension in the emergency department and linkage to care: A prospective cohort study in Tanzania

OBJECTIVES

Globally, hypertension affects one billion people and disproportionately burdens low-and middle-income countries. Despite the high disease burden in sub-Saharan Africa, optimal care models for diagnosing and treating hypertension have not been established. Emergency departments (EDs) are frequently the first biomedical healthcare contact for many people in the region. ED encounters may offer a unique opportunity for identifying high risk patients and linking them to care.

METHODS

Between July 2017 and March 2018, we conducted a prospective cohort study among patients presenting to a tertiary care ED in northern Tanzania. We recruited adult patients with a triage blood pressure ≥ 140/90 mmHg in order to screen for hypertension. We explored knowledge, attitudes and practices for hypertension using a questionnaire, and assessed factors associated with successful follow-up. Hypertension was defined as a single blood pressure measurement ≥ 160/100 mmHg or a three-time average of ≥ 140/90 mmHg. Uncontrolled hypertension was defined as a three-time average measurement of ≥ 160/100 mmHg. Successful follow-up was defined as seeing an outpatient provider within one month of the ED visit.

RESULTS

We enrolled 598 adults (mean age 59.6 years), of whom 539 (90.1%) completed the study. The majority (78.6%) of participants were aware of having hypertension. Many (223; 37.2%) had uncontrolled hypertension. Overall, only 236 (43.8%) of participants successfully followed-up within one month. Successful follow-up was associated with a greater understanding that hypertension requires lifelong treatment (RR 1.11; 95% CI 1.03,1.21) and inversely associated with greater anxiety about the future (RR 0.80; 95% CI 0.64,0.99).

CONCLUSION

In a northern Tanzanian tertiary care ED, the burden of hypertension is high, with few patients receiving optimal outpatient care follow-up. Multi-disciplinary strategies are needed to improve linkage to care for high-risk patients from ED settings.

hnRNP K plays a protective role in TNF-α-induced apoptosis in podocytes

Apoptosis of podocytes contributes to proteinuria in many chronic kidney diseases. The cytokine, tumor necrosis factor-α (TNF-α) is thought to be involved in podocyte apoptosis, but the underlying mechanism is not understood. In our study, we established a model of TNF-α-induced apoptosis by isolating primary podocytes from mice. After exposing cells to TNF-α, we determined the expression levels of heterogeneous nuclear ribonucleoprotein K (hnRNP K) and cellular FLICE-inhibitory protein (c-FLIP) and the phosphorylation levels of glycogen synthase kinase β (GSK3β) and extracellular signal-regulated kinase (ERK). We then knocked down or overexpressed the levels of hnRNP K and observed its effects on the expressions of c-FLIP, caspase-8, caspase-3, and the phosphorylation of GSK3β and ERK. In addition, we examined the percentage of cells undergoing apoptosis and studied cell cycle distribution. We found that TNF-α induced apoptosis in podocytes and that the expressions of hnRNP K and c-FLIP were significantly decreased, whereas the phosphorylations of GSK3β and ERK were significantly increased. Both gene knockdown and overexpression of hnRPN K resulted in varied expressions/phosphorylations of c-FLIP, GSK3β, and ERK. Moreover, decreased hnRPN K expression contributed to increased levels of caspase-8 and capase-3, as well as an increase in cell apoptosis and G0/G1 arrest. In conclusion, down-regulated expression of hnRNP K by TNF-α resulted in a decrease in the expression of c-FLIP as well as increases in phosphorylated GSK3β, ERK, caspase-8, and caspase-3, and then critically contributed to the podocyte apoptosis.

Time-Centered Approach to Understanding Risk Factors for the Progression of CKD

BACKGROUND AND OBJECTIVES

Traditional approaches to modeling risk of CKD progression do not provide estimates of the time it takes for disease progression to occur, which could be useful in guiding therapeutic interactions between patients and providers. Our objective was to estimate median time spent in each of CKD stages 3a-5 and how the time differs according to risk factors associated with progression of disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We included 3682 participants of the Chronic Renal Insufficiency Cohort in mixed models to estimate person-specific trajectories of function, and used these trajectories to estimate time spent in each CKD stage.

RESULTS

During 9.5 years of median follow-up, participants spent longer in earlier rather than later CKD stages, ranging from a median of 7.9 years (interquartile range, 2.3 to >12 years) in stage 3a to 0.8 years (interquartile range, 0.3-1.6) in stage 5. Known risk factors for CKD progression were also associated with larger differences in time until progression to the next CKD stage in earlier versus later stages of disease. For example, compared with systolic BP <140 mm Hg, systolic BP ≥140 mm Hg was associated with 6.1 years shorter time (95% confidence interval [95% CI], 4.5 to 7.5) spent in stage 3a, 3.3 years shorter time (95% CI, 2.7 to 4.0) in stage 3b, but only 2.4 months shorter time (95% CI, 0.8 to 3.6) in stage 5. Compared with those with proteinuria <1 g/g, proteinuria ≥1 g/g was associated with 8 years shorter time spent (95% CI, 6.8 to 9.6) in stage 3a, 5.6 years shorter time (95% CI, 5.0 to 6.4) in stage 3b, but only 6 months shorter time (95% CI, 3.8 to 8) in stage 5.

CONCLUSIONS

There are marked variations in the time spent in the different stages of CKD, according to risk factors and stage of disease.