Effects of bariatric surgery on renal function: a retrospective cohort study comparing one-year outcomes between one-anastomosis gastric bypass and Roux-en-Y gastric bypass.

BACKGROUND: Evidence on the effect of one-anastomosis gastric bypass (OAGB) on renal function is limited. OBJECTIVE: To compare the evolution of estimated renal function observed 1 year after OAGB and Roux-en-Y gastric bypass (RYGB) in individuals with obesity. DESIGN AND SETTING: Observational, analytical, and retrospective cohort study. Tertiary-level university hospital. METHODS: This study used a prospectively collected database of individuals who consecutively underwent bariatric surgery. Renal function was assessed by calculating the estimated glomerular filtration rate (eGFR), according to the Chronic Kidney Disease Epidemiology Collaboration. The one-year variation in the eGFR was compared between the procedures. RESULTS: No significant differences in age, sex, obesity-associated conditions, or body mass index were observed among individuals who underwent either OAGB or RYGB. OAGB led to a significantly higher percentage of total (P = 0.007) and excess weight loss (P = 0.026). Both OAGB and RYGB led to significantly higher values of eGFR (103.9 ± 22 versus 116.1 ± 13.3; P = 0.007, and 102.4 ± 19 versus 113.2 ± 13.3; P < 0.001, respectively). The one-year variation in eGFR was 11 ± 16.2% after OAGB and 16.7 ± 26.3% after RYGB (P = 0.3). Younger age and lower baseline eGFR were independently associated with greater postoperative improvement in renal function (P < 0.001). CONCLUSION: Compared with RYGB, OAGB led to an equivalent improvement in renal function 1 year after the procedure, along with greater weight loss.

Lean body mass in living kidney donors impacts postoperative renal function.

PURPOSE: A living donor kidney transplant is the optimal treatment for chronic renal impairment. Our objective is to assess if lean skeletal muscle mass and donor factors such as body mass index, hypertension, and age impact on renal function following donor nephrectomy. METHODS: Potential donors undergo CT angiography as part of their work-up in our institution. Using dedicated software (Horos®), standardized skeletal muscle area measured at the L3 vertebrae was calculated. When corrected for height, skeletal muscle index can be derived. Skeletal muscle mass index below predefined levels was classified as sarcopenic. The correlation of CT-derived skeletal muscle index and postoperative renal function at 12 months was assessed. Co-variables including donor gender, age, body mass index (BMI), and presence of pre-op hypertension were also assessed for their impact on postoperative renal function. RESULTS: 275 patients who underwent living donor nephrectomy over 10 years were included. Baseline pre-donation glomerular filtration rate (GFR) and renal function at one year post-op were similar between genders. 29% (n = 82) of patients met the criteria for CT-derived sarcopenia. Sarcopenic patients were more likely to have a higher GFR at one year post-op (69.3 vs 63.9 mL/min/1.73 m2, p < 0.001). The main factors impacting better renal function at one year were the presence of sarcopenia and younger age at donation. CONCLUSION: When selecting donors, this study highlights that patients with low skeletal mass are unlikely to underperform in terms of recovery of their renal function postoperatively at one year when compared to patients with normal muscle mass and should not be a barrier to kidney donation.

Recent Update on Acute Kidney Injury-to-Chronic Kidney Disease Transition.

Acute kidney injury (AKI) is characterized by an abrupt decline of excretory kidney function. The incidence of AKI has increased in the past decades. Patients diagnosed with AKI often undergo diverse clinical trajectories, such as early or late recovery, relapses, and even a potential transition from AKI to chronic kidney disease (CKD). Although recent clinical studies have demonstrated a strong association between AKI and progression of CKD, our understanding of the complex relationship between AKI and CKD is still evolving. No cohort study has succeeded in painting a comprehensive picture of these multi-faceted pathways. To address this lack of understanding, the idea of acute kidney disease (AKD) has recently been proposed. This presents a new perspective to pinpoint a period of heightened vulnerability following AKI, during which a patient could witness a substantial decline in glomerular filtration rate, ultimately leading to CKD transition. Although AKI is included in a range of kidney conditions collectively known as AKD, spanning from mild and self-limiting to severe and persistent, AKD can also occur without a rapid onset usually seen in AKI, such as when kidney dysfunction slowly evolves. In the present review, we summarize the most recent findings about AKD, explore the current state of biomarker discovery related to AKD, discuss the latest insights into pathophysiological underpinnings of AKI to CKD transition, and reflect on therapeutic challenges and opportunities that lie ahead.

Frail hypertensive older adults with prediabetes and chronic kidney disease: insights on organ damage and cognitive performance - preliminary results from the CARYATID study.

BACKGROUND: Hypertension and chronic kidney disease (CKD) pose significant public health challenges, sharing intertwined pathophysiological mechanisms. Prediabetes is recognized as a precursor to diabetes and is often accompanied by cardiovascular comorbidities such as hypertension, elevating the risk of pre-frailty and frailty. Albuminuria is a hallmark of organ damage in hypertension amplifying the risk of pre-frailty, frailty, and cognitive decline in older adults. We explored the association between albuminuria and cognitive impairment in frail older adults with prediabetes and CKD, assessing cognitive levels based on estimated glomerular filtration rate (eGFR). METHODS: We conducted a study involving consecutive frail older patients with hypertension recruited from March 2021 to March 2023 at the ASL (local health unit of the Italian Ministry of Health) of Avellino, Italy, followed up after three months. Inclusion criteria comprised age over 65 years, prior diagnosis of hypertension without secondary causes, prediabetes, frailty status, Montreal Cognitive Assessment (MoCA) score < 26, and CKD with eGFR > 15 ml/min. RESULTS: 237 patients completed the study. We examined the association between albuminuria and MoCA Score, revealing a significant inverse correlation (r: 0.8846; p < 0.0001). Subsequently, we compared MoCA Score based on eGFR, observing a significant difference (p < 0.0001). These findings were further supported by a multivariable regression analysis, with albuminuria as the dependent variable. CONCLUSIONS: Our study represents the pioneering effort to establish a significant correlation between albuminuria and eGFR with cognitive function in frail hypertensive older adults afflicted with prediabetes and CKD.

Urinary Cell Cycle Arrest Biomarkers and Diuretic Efficiency in Acute Heart Failure.

INTRODUCTION: This study aimed to evaluate the association between the NephroCheck® test AKIRisk® score, diuretic efficiency (DE), and the odds of worsening kidney function (WKF) within the first 72 h of admission in patients hospitalized for acute heart failure (AHF). METHODS: The study prospectively enrolled 125 patients admitted with AHF. NephroCheck® test was obtained within the first 24 h of admission. DE was defined as net fluid urine output per 40 mg of furosemide equivalents. RESULTS: The median AKIRisk® score was 0.11 (IQR 0.06-0.34), and 38 (30.4%) patients had an AKIRisk® score >0.3. The median cumulative DE at 72 h was 1,963 mL (IQR 1317-3,239 mL). At 72 h, a total of 10 (8%) patients developed an absolute increase in sCr ≥0.5 mg/dL (WKF). In a multivariable setting, there was an inverse association between the AKIRisk® score and DE within the first 72 h. In fact, the highest the AKIRisk® score (centered at 0.3), the higher the likelihood of poor DE (below the median) and WKF at 72 h (odds ratio [OR] 2.04; 95%; CI: 1.02-4.07; p = 0.043, and OR 3.31, 95% CI: 1.30-8.43; p = 0.012, respectively). CONCLUSION: In patients with AHF, a higher NephroCheck® AKIRisk® score is associated with poorer DE and a higher risk of WKF at 72 h. Further research is needed to confirm the role of urinary cell cycle arrest biomarkers in the AHF scenario.

Circulating TNF receptor levels are associated with estimated glomerular filtration rate even in healthy individuals with normal kidney function.

The association between serum tumor necrosis factor receptor (TNFRs: TNFR1, TNFR2) levels and estimated glomerular filtration rate (eGFR) observed in patients with diabetes has not been comprehensively tested in healthy subjects with normal kidney function. It also remains unclear whether TNFR levels differ by age and sex, and between healthy subjects and diabetics. We measured serum TNFR levels in 413 healthy subjects and 292 patients with type 2 diabetes. In healthy subjects, TNFR levels did not differ between men and women. Additionally, TNFR2, but not TNFR1, levels increased with age. In multivariate analysis, TNFR1 was associated only with cystatin C-based eGFR (eGFR-CysC), whereas TNFR2 was associated with systolic blood pressure in addition to eGFR-CysC. Both TNFRs were associated with lower eGFR (eGFR-Cys < 90 mL/min/1.73 m2) even after adjustment for relevant clinical factors. Upon combining healthy subjects and patients with diabetes, the presence of diabetes and elevated glycated hemoglobin level were significant factors in determining TNFR levels. TNFR levels were associated with eGFR-CysC, but were not affected by age and sex in healthy subjects with normal kidney function. TNFR levels in patients with diabetes appeared to be higher than in healthy subjects.

Development of a formula for estimated glomerular filtration rate in pregnant women from physiological hyperfiltration of serum creatinine.

Increased body fluids during pregnancy complicates the application of estimated glomerular filtration rate (eGFR) formulas that are based on body surface area. Furthermore, gestational renal dysfunction cannot be identified if the serum creatinine (SCr) concentration is within the non-pregnant reference interval (RI) despite inadequate pregnancy-related renal hyperfiltration. 1484 SCr measurements from 957 healthy pregnant women were collected. The average SCr value of gestational week (GW) 0-3 was the representative SCr value of non-pregnant status. While the distribution of SCr measurements varied across GWs, it was transformed into a normal distribution using the bootstrap resampling method. A polynomial linear regression method was applied to achieve a continuous and smooth transformation of values. The normally distributed SCr values of each GW were compared to the non-pregnant status, leading to the calculation of SCr hyperfiltration. The final equation, (2 - SCr (µmol/L) / 55.25) × 103.1 × 55.25/(56.7 - 0.223 × GW - 0.113 × GW2 + 0.00545 × GW3 - 0.0000653 × GW4), and reference intervals for both SCr and eGFR for each GW were obtained. These RIs and novel equations can be effectively used to monitor renal dysfunction in pregnant women.

Risk factors for lower renal compensation after nephrectomy: an analysis of living kidney donors in an Amazonian cohort.

INTRODUCTION: Living donor kidney transplantation is considered the ideal renal replacement therapy because it has a lower complication rate and allows an efficient response to the high demand for grafts in the healthcare system. Careful selection and adequate monitoring of donors is a key element in transplantation. Individuals at greater risk of developing kidney dysfunction after nephrectomy must be identified. OBJECTIVE: To identify risk factors associated with a renal compensation rate (CR) below 70% 12 months after nephrectomy. METHODS: This observational retrospective longitudinal study included living kidney donors followed up at the Lower Amazon Regional Hospital between 2016 and 2022. Data related to sociodemographic variables, comorbid conditions and kidney function parameters were collected. RESULTS: The study enrolled 32 patients. Fourteen (43.75%) had a CR < 70% 12 months after kidney donation. Logistic regression found obesity (Odds Ratio [95%CI]: 10.6 [1.7-65.2]), albuminuria (Odds Ratio [95%CI]: 2.41 [1.2-4.84]) and proteinuria (Odds Ratio [95%CI]: 1.14 [1.03-1.25]) as risk factors. Glomerular filtration rate was a protective factor (Odds Ratio [95% CI]: 0.92 [0.85-0.99]). CONCLUSION: Obesity, albuminuria and proteinuria adversely affected short-term renal compensation rate. Further studies are needed to uncover the prognostic implications tied to these risk factors. Our findings also supported the need for careful individualized assessment of potential donors and closer monitoring of individuals at higher risk.

Limitations of Parenchymal Volume Analysis for Estimating Split Renal Function and New Baseline Glomerular Filtration Rate After Radical Nephrectomy.

PURPOSE: Accurately predicting new baseline glomerular filtration rate (NBGFR) after radical nephrectomy (RN) can improve counseling about RN vs partial nephrectomy. Split renal function (SRF)-based models are optimal, and differential parenchymal volume analysis (PVA) is more accurate than nuclear renal scans (NRS) for this purpose. However, there are minimal data regarding the limitations of PVA. Our objective was to identify patient-/tumor-related factors associated with PVA inaccuracy. MATERIALS AND METHODS: Five hundred and ninety-eight RN patients (2006-2021) with preoperative CT/MRI were retrospectively analyzed, with 235 also having NRS. Our SRF-based model to predict NBGFR was: 1.25 × (GlobalGFRPre-RN × SRFContralateral), where GFR indicates glomerular filtration rate, with SRF determined by PVA or NRS, and with 1.25 representing the median renal functional compensation in adults. Accuracy of predicted NBGFR within 15% of observed was evaluated in various patient/tumor cohorts using multivariable logistic regression analysis. RESULTS: PVA and NRS accuracy were 73%/52% overall, and 71%/52% in patients with both studies (n = 235, P < .001), respectively. PVA inaccuracy independently associated with pyelonephritis, hydronephrosis, renal vein thrombosis, and infiltrative features (all P < .03). Ipsilateral hydronephrosis and renal vein thrombosis associated with PVA underprediction, while contralateral hydronephrosis and increased age associated with PVA overprediction (all P < .01). NRS inaccuracy was more common and did not associate with any of these conditions. Even among cohorts where PVA inaccuracy was observed (22% of our patients), there was no significant difference in the accuracies of NRS- and PVA-based predictions. CONCLUSIONS: PVA was more accurate for predicting NBGFR after RN than NRS. Inaccuracy of PVA correlated with factors that distort the parenchymal volume/function relationship or alter renal functional compensation. NRS inaccuracy was more common and unpredictable, likely reflecting the inherent inaccuracy of NRS. Awareness of cohorts where PVA is less accurate can help guide clinical decision-making.

Trajectories of Kidney Function in Heart Failure Over a 15-Year Follow-Up: Clinical Profiling and Mortality.

BACKGROUND: Limited data are available on the long-term trajectory of estimated glomerular filtration rate (eGFR) in patients with chronic heart failure. OBJECTIVES: The authors evaluated eGFR dynamics using the 2009 Chronic Kidney Disease Epidemiology Collaboration equation and its prognostic significance in a real-world cohort over a 15-year follow-up. METHODS: A prospective observational registry of ambulatory heart failure outpatients was conducted, with regular eGFR assessments at baseline and on a 3-month schedule for ≤15 years. Urgent kidney function assessments were excluded. Locally weighted error sum of squares curves were plotted for predefined subgroups. Multivariable longitudinal Cox regression analyses were conducted to assess associations with all-cause and cardiovascular death. RESULTS: A total of 2,672 patients were enrolled consecutively between August 2001 and December 2021. The average age was 66.8 ± 12.6 years, and 69.8% were men. Among 40,970 creatinine measurements, 28,634 were used for eGFR analysis, averaging 10.7 ± 8.5 per patient. Over the study period, a significant decline in eGFR was observed in the entire cohort, with a slope of -1.70 mL/min/1.73 m2 per year (95% CI: -1.75 to -1.66 mL/min/1.73 m2 per year). Older patients, those with diabetes, a preserved ejection fraction, a higher baseline eGFR, elevated hospitalization rates, and those who died during follow-up experienced more pronounced decreases in the eGFR. Moreover, the decrease in kidney function correlated independently with all-cause mortality and cardiovascular death. CONCLUSIONS: These findings highlight the sustained decline in eGFR over 15 years in patients with heart failure, with variations based on clinical characteristics, and emphasize the importance of regular eGFR monitoring in this population.

Urinary Prostaglandin E2 Excretion and the Risk of Cardiovascular and Kidney Disease.

BACKGROUND: Inhibition of prostaglandin synthesis by nonsteroidal anti-inflammatory drugs is associated with cardiovascular mortality and kidney disease. This study hypothesizes that urinary prostaglandin E2 (PGE2) and PGE2 metabolite (PGEM) excretions are markers of cardiovascular and kidney health, because they reflect both systemic and kidney-derived PGE2 production. METHODS AND RESULTS: PGE2 and PGEM were measured in spot urine samples from 2291 participants (≥55 years old) of the population-based Rotterdam Study. Urinary PGE2 and PGEM excretions were analyzed using linear regression analyses to identify cross-sectional associations with cardiovascular risk factors and baseline estimated glomerular filtration rate (eGFR). Longitudinal associations with cardiovascular mortality and kidney outcomes (eGFR <60 or <45 mL/min per 1.73 m2 and the composite outcome 40% eGFR loss or kidney failure) were assessed with Cox regression. Urinary PGE2 and PGEM excretions were higher with increasing age, lower eGFR, smoking, diabetes, and albuminuria. A 2-fold higher urinary PGE2 and PGEM excretion was associated with a higher risk of cardiovascular mortality (28 825 patient-years; 160 events; PGE2 hazard ratio [HR], 1.27, [95% CI, 1.06-1.54]; PGEM HR, 1.36 [95% CI, 1.10-1.67]). Higher PGE2 excretions were also associated with a higher risk of incident eGFR <60 mL/min per 1.73 m2 (31 530 person-years; 691 events; HR, 1.13 [95% CI, 1.02-1.25]) with similar HRs for the other kidney outcomes. CONCLUSIONS: Urinary PGE2 and PGEM excretions are novel markers for the presence and progression of cardiovascular and kidney disease. Future studies should address whether these associations are causal and can be targeted to improve cardiovascular and kidney outcomes.

Biological variation in the estimated glomerular filtration rate of healthy individuals within 24 h calculated using 2021CKD-EPI equations.

BACKGROUND AND AIMS: Use the MDRD (Modification of Diet in Renal Disease) and 2021 CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation void of race coefficients (CKD-EPICrea, CKD-EPICys-C, and CKD-EPICrea+Cys-C) to estimate the BV (Biological variation) of eGFR (estimated glomerular filtration rate) within 24 h in a healthy population to help explain future studies using eGFR in the context of a known BV. METHODS: Blood samples were collected from 30 healthy subjects at six time points within 24 h. Serum creatinine (S-Crea) and serum cystatin C (S-Cys-C) were measured, and the BV of eGFR was calculated. Outlier and variance homogeneity analyses were performed, followed by CV-ANOVA on trend-corrected data. RESULTS: The eGFR CVI for the four equations (MDRD, CKD-EPICrea, CKD-EPICys-C, and CKD-EPICrea+Cys-C) were 8.39% (7.50-9.51%), 3.90% (3.49-4.42%), 6.58% (5.88-7.46%), and 5.03% (4.50-5.71%), respectively. The corresponding II and RCVpos/neg values were 0.69, 0.48, 0.51, and 0.31, and (29.30%, - 22.66%), (12.69%, - 11.2 6%), (20.97%, - 17.33%), and (15.88%, - 13.70%), respectively; RCVpos /neg of eGFR was highest in the MDRD equation and lowest in the CKD-EPI Crea equation. Additionally, the RCVpos/neg values of the individual was highest in the MDRD equation and lowest in the CKD-EPICrea+Cys-C equation; they are (56.51%, - 36.11%) and (5.01%, - 4.77%), respectively. CONCLUSIONS: We present data on the 24 h BV eGFR of the 2021 CKD-EPI equations. The presence of BV has impact on the interpretation of GFR results, affecting CKD disease grading. The RCVpos/neg differences were large among the individuals. When using eGFRs based on the MDRD and CKD-EPI equations, it is necessary to combine RCVpos/neg values before interpreting the results.

Cumulative blood pressure load and hypertensive nephropathy in Han Chinese hypertensive patients.

The study aims to assess the relationship between cumulative blood pressure load (cBPL) and the risk of renal function decline in hypertensive patients and determine the blood pressure (BP) threshold required to prevent hypertensive nephropathy. A single-center prospective cohort study was conducted on hypertensive patients. The cBPL was defined as the proportion of area beyond variable BP cutoffs under ambulatory BP monitoring. Renal events were defined as > 25% (minor) or > 50% (major) decline of baseline estimated glomerular filtration rate (eGFR). Cox regression analysis was conducted between cBPL, other ambulatory BP parameters, and renal events. The results revealed a total of 436 Han Chinese hypertensive patients were eligible for enrollment. During an average follow-up period of 5.1 ± 3.3 years, a decline of > 25% and > 50% in eGFR was observed in 77 and eight participants, respectively. Cox regression analysis revealed that cSBPL140 (hazard ratio [HR], 1.102; 95% confidence interval [CI], 1.017-1.193; p = .017), cSBPL130 (HR, 1.076; 95% CI, 1.019-1.137; p = .008), and cSBPL120 (HR, 1.054; 95% CI, 1.010-1.099; p = .015) were independently associated with minor renal events. Similarly, cSBPL140 (HR, 1.228; 95% CI, 1.037-1.455; p = .017), cSBPL130 (HR, 1.189; 95% CI, 1.045-1.354; p = .009), and cSBPL120 (HR, 1.155; 95% CI, 1.039-1.285; p = .008) were independently associated with major renal events. In conclusion, cBPL is associated with renal function decline in hypertensive patients. Minimizing cBPL120 may decrease the risk of hypertensive nephropathy.