Association of age and BMI with kidney function and mortality: a cohort study

The potential causal relationship between BMI, T1D, urolithiasis, and hydronephrosis in European ancestry: A Mendelian randomization analysis

Body mass index (BMI), type 1 diabetes (T1D), urolithiasis, and hydronephrosis are interrelated. Our aim was to analyze their causal relationships at the genetic level. Mendelian randomization is an instrumental variable analysis method that follows Mendel genetic law of random allocation of parental alleles to offspring. In observational studies, genetic variants are used as instrumental variables to infer causal relationships between exposure factors and study outcomes. All the genome-wide association study data in our study were publicly available and from published genome-wide association studies, UK Biobank, and FinnGen. Random-effects inverse variance weighted was the primary analysis method, with R Egger, weighted median, and weighted mode as supplementary methods. We examined heterogeneity, horizontal pleiotropy, and the influence of individual single nucleotide polymorphisms on the analysis. We further explored the causal relationships between BMI, T1D, urolithiasis, and hydronephrosis, as well as the robustness of the analysis results. Inverse variance weighted results showed genetic causal relationships between BMI (P = .034, odds ratio [OR] 95% confidence interval [CI] = 1.273 [1.019-1.589]), T1D (P = .028, OR 95% CI = 0.921 [0.855-0.991]), urolithiasis (P < .001, OR 95% CI = 1.361 [1.175-1.576]), and hydronephrosis. Sensitivity analyses confirmed the accuracy and robustness of these findings. Our results support significant causal roles of BMI, T1D, and urolithiasis in hydronephrosis, potentially offering new intervention strategies for preventing its development.

The Kidney in Obesity: Current Evidence, Perspectives and Controversies

PURPOSE OF REVIEW

As obesity and chronic kidney disease (CKD) remain a public health issue, we aim to elaborate on their complex relationship regarding pathogenetic mechanisms and therapeutic potential as well. The purpose of this review is to enhance our understanding of the interplay between obesity and CKD in order to timely diagnose and treat obesity-related CKD.

RECENT FINDINGS

Obesity and CKD pose significant intertwined challenges to global health, affecting a substantial portion of the population worldwide. Obesity is recognized as an independent risk factor, intricately contributing to CKD pathogenesis through mechanisms such as lipotoxicity, chronic inflammation, and insulin resistance. Recent evidence highlights additional factors including hemodynamic changes and intestinal dysbiosis that exacerbate kidney dysfunction in obese individuals, leading to histologic alterations known as obesity-related glomerulopathy (ORG). This narrative review synthesizes current knowledge on the prevalence, pathophysiology, clinical manifestations, and diagnostic strategies of obesity-related kidney disease. Furthermore, it explores mechanistic insights to delineate current therapeutic approaches, future directions for managing this condition and controversies. By elucidating the multifaceted interactions between obesity and kidney health, this review aims to inform clinical practice and stimulate further research to address this global health epidemic effectively.

Association between visceral adiposity index and incidence of diabetic kidney disease in adults with diabetes in the United States

Visceral adiposity index (VAI) is a reliable indicator of visceral adiposity. However, no stu-dies have evaluated the association between VAI and DKD in US adults with diabetes. Theref-ore, this study aimed to explore the relationship between them and whether VAI is a good pr-edictor of DKD in US adults with diabetes. Our cross-sectional study included 2508 participan-ts with diabetes who were eligible for the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018. Univariate and multivariate logistic regression were used to an-alyze the association between VAI level and DKD. Three models were used to control for pot-ential confounding factors, and subgroup analysis was performed for further verification. A tot-al of 2508 diabetic patients were enrolled, of whom 945 (37.68%) were diagnosed with DKD. Overall, the VAI was 3.36 ± 0.18 in the DKD group and 2.76 ± 0.11 in the control group. VAI was positively correlated with DKD (OR = 1.050, 95% CI 1.049, 1.050) after fully adjusting for co-nfounding factors. Compared with participants in the lowest tertile of VAI, participants in the highest tertile of VAI had a significantly increased risk of DKD by 35.9% (OR = 1.359, 95% CI 1.355, 1.362). Through subgroup analysis, we found that VAI was positively correlated with the occurrence of DKD in all age subgroups, male(OR = 1.043, 95% CI 1.010, 1.080), participants wit-hout cardiovascular disease(OR = 1.038, 95% CI 1.011, 1.069), hypertension (OR = 1.054, 95% CI 1.021, 1.090), unmarried participants (OR = 1.153, 95% CI 1.036, 1.294), PIR < 1.30(OR = 1.049, 95% CI 1.010, 1.094), PIR ≧ 3 (OR = 1.085, 95% CI 1.021, 1.160), BMI ≧ 30 kg/m2 (OR = 1.050, 95% CI 1.016, 1.091), former smokers (OR = 1.060, 95% CI 1.011, 1.117), never exercised (OR = 1.033, 95% CI 1.004, 1.067), non-Hispanic white population (OR = 1.055, 95% CI 1.010, 1.106) and non-Hipanic black population (OR = 1.129, 95% CI 1.033, 1.258). Our results suggest that elevated VAI levels are closely associated with the development of DKD in diabetic patients. VAI may be a simpl-e and cost-effective index to predict the occurrence of DKD. This needs to be verified in furt-her prospective investigations.

Clinical implications of four different nutritional indexes in patients with IgA nephropathy

Background

Immunoglobulin A nephropathy (IgAN) is the most prevalent form of chronic kidney disease (CKD), marked by diverse pathological patterns and variable prognostic outcomes. Nutritional indexes are crucial for disease assessment and prognosis prediction. This study investigates associations between nutritional indexes and renal function in patients with IgAN.

Methods

A cohort of 736 adults diagnosed with IgAN, who underwent renal biopsy at the First Hospital of Jilin University between January 2010 and October 2022, was examined. Clinical and laboratory data were reviewed, and four nutritional indexes were calculated: controlling nutritional status (CONUT) score, geriatric nutritional risk index (GNRI), body mass index (BMI), and prognostic nutritional index (PNI). Cox-proportional hazard analysis evaluated factors associated with end-stage renal disease (ESRD).

Results

Patients with ESRD showed significantly lower GNRI (91.84 vs. 98.94, p < 0.001) and median PNI (41.90 vs. 46.30, p < 0.001), with higher median CONUT score (2.00 vs. 1.00, p = 0.001) compared to those without ESRD. PNI, GNRI, and CONUT scores correlated significantly with C2 in MEST-C classification. Kaplan-Meier analysis indicated increased ESRD probability in individuals with specific thresholds of PNI, GNRI, or CONUT scores. Additionally, GNRI emerged as an independent predictor of ESRD (hazard ratio: 0.963, 95% CI: 0.940-0.979, p < 0.001), along with platelet count, serum creatinine, eGFR (CKD-EPI), and triglyceride levels.

Conclusion

GNRI, PNI, and CONUT scores hold potential in reflecting IgAN severity and predicting ESRD risk. GNRI especially may serve as a valuable tool for identifying high-risk individuals for ESRD in IgAN.

The Role of Dietary Acid Load on Progression of Estimated Glomerular Filtration Rate Among Individuals Diagnosed With Chronic Kidney Disease

OBJECTIVE

Individuals with chronic kidney disease (CKD) are at an increased risk for developing metabolic acidosis. Metabolic acidosis has been shown to worsen kidney function and exacerbate systemic inflammation. Diets high in protein foods can exacerbate metabolic acidosis as protein foods tend to be more acidic, while fruits and vegetables are more alkalotic. The main objective of this systematic review was to determine if higher consumption of fruits and vegetables in adults with CKD stages 1-5 reduces the rate of decline of estimated glomerular filtration rate.

METHODS

Searches of Cumulated Index to Nursing and Allied Health Literature (CINAHL -Elton B. Stephens Company [EBSCO]), Cochrane Library (Wiley), Dissertation & Thesis Global (ProQuest), Embase (Elsevier), Medline (OVID), PubMed (National Library of Medicine), Scopus (Elsevier), and Web of Sciences (Clarivate) identified 1,451 articles published between January 2015 and June 2023.

RESULTS

After independent review, 7 total studies were included. Six of the studies found an association between dietary acid load and progression of CKD.

CONCLUSIONS

Dietary counseling focusing on decreasing dietary acid load may be beneficial for individuals with CKD.

Exploring the complex dynamics of BMI, age, and physiological indicators in early adolescents

BACKGROUND AND OBJECTIVES

To investigate the relationship between body mass index (BMI) and blood biochemical indicators in early adolescence, and to provide ideas for early prevention of diseases and explore possible disease-related predictors.

METHODS

3125 participants aged 10 ∼ 14 years were selected from China from the survey of "China Nutrition and Health Surveillance ( 2016 ∼ 2017 ) ". Employing advanced statistical methods, including generalized linear models, heatmaps, hierarchical clustering, and generalized additive models, the study delved into the associations between BMI and various biochemical indicators.

RESULTS

In early adolescence, indicators including systolic pressure, diastolic pressure, weight, height, BMI, hemoglobin, blood uric acid, serum creatinine, albumin, vitamin A presented increasing trends with the increase of age ( P < 0.05 ), whereas LDL-C, vitamin D, and ferritin showed decreasing trends with the increase of age ( P < 0.05 ). The increase in hemoglobin and blood uric acid levels with age was more pronounced in males compared to females ( P < 0.05 ). BMI was positively correlated with blood glucose, hemoglobin, triglyceride, LDL-C, blood uric acid, serum creatinine, ferritin, transferrin receptor, hs-CRP, total protein, vitamin A ( P < 0.05 ). There was a significant BMI × age interaction in the correlation analysis with LDL-C, transferrin receptor, serum creatinine, and hs-CRP ( P < 0.05 ). BMI was a risk factor for hypertension, hypertriglyceridemia, low high density lipoprotein cholesterolemia, and metabolic syndrome in all age groups ( OR > 1, P < 0.05 ).

CONCLUSIONS

High BMI was a risk factor for hypertension, hypertriglyceridemia, low high density lipoprotein cholesterolemia, and MetS in early adolescents. With the focus on energy intake beginning in early adolescence, the maintenance of a healthy weight warrants greater attention.

Collaborative Approach Toward Transplant Candidacy for Obese Patients with End-Stage Renal Disease

BACKGROUND

An elevated BMI is a major cause of transplant preclusion for patients with end-stage renal disease (ESRD). This phenomenon exacerbates existing socioeconomic and racial disparities and increases the economic burden of maintaining patients on dialysis. Metabolic bariatric surgery (MBS) in such patients is not widely available. Our center created a collaborative program to undergo weight loss surgery before obtaining a kidney transplant.

STUDY DESIGN

We studied the outcomes of these patients after MBS and transplant surgery. One hundred eighty-three patients with ESRD were referred to the bariatric team by the transplant team between January 2019 and June 2023. Of these, 36 patients underwent MBS (20 underwent Roux-en-Y gastric bypass and 16 underwent sleeve gastrectomy), and 10 underwent subsequent transplantation, with another 15 currently waitlisted. Both surgical teams shared resources, including dieticians, social workers, and a common database, for easy transition between teams.

RESULTS

The mean starting BMI for all referrals was 46.4 kg/m 2 and was 33.9 kg/m 2 at the time of transplant. The average number of hypertension medications decreased from 2 (range 2 to 4) presurgery to 1 (range 1 to 3) postsurgery. Similarly, hemoglobin A1C levels improved, with preoperative averages at 6.2 (range 5.4 to 7.6) and postoperative levels at 5.2 (range 4.6 to 5.8) All transplants are currently functioning, with a median creatinine of 1.5 (1.2 to 1.6) mg/dL (glomerular filtration rate 46 [36.3 to 71]).

CONCLUSIONS

A collaborative approach between bariatric and transplant surgery teams offers a pathway toward transplant for obese ESRD patients and potentially alleviates existing healthcare disparities. ESRD patients who undergo MBS have unique complications to be aware of. The improvement in comorbidities may lead to superior posttransplant outcomes.

Central Body Fat Distribution and Kidney Function after Living Kidney Donation

BACKGROUND

In most screening guidelines, high body mass index (BMI) is considered a contraindication for kidney donation. New insights suggest that central body fat distribution might provide greater power in assessing kidney risk. This study aimed to determine whether BMI and central body fat distribution measures are associated with long-term kidney function after donor nephrectomy. We hypothesized that higher BMI, waist circumference (WC), and waist-to-height ratio (WHtR) were associated with lower kidney function long term after donation.

METHODS

The study population consisted of living kidney donors. BMI, WC, and WHtR were measured during donor screening. The outcome postdonation kidney function was assessed using measured GFR (mGFR) (mGFR, 125 I-iothalamate infusion) at 3 months ( n =1042), 5 years ( n =556), and 10 years ( n =210) of follow-up. Primary multivariable linear regression analyses were performed with BMI and WC and secondary analyses with WHtR. Linear mixed models were performed to investigate change in postdonation eGFR.

RESULTS

The donor age was 52±11 years, and 48% were male. The mean BMI was 26.1±3.6 kg/m 2 , and WC was 91±11 cm. Higher predonation BMI was associated with lower mGFR throughout follow-up: -1.35 (95% confidence interval [CI], -1.95 to -0.80), -1.55 (95% CI, -2.50 to -0.65), and -2.35 (95% CI, -4.10 to -0.60) ml/min per m 2 per 5 kg/m 2 higher BMI at 3 months, 5, and 10 years after donation, respectively, adjusted for sex, age, and predonation GFR. For WC, differences in mGFR were -1.30 (95% CI, -1.70 to -0.90), -1.50 (95% CI, -2.20 to -0.80), and -1.70 (95% CI, -3.00 to -0.50) ml/min per m 2 per 10 cm higher WC at 3 months, 5, and 10 years after donation, respectively. In male donors, BMI and WC were significantly associated with a negative postdonation change in eGFR.

CONCLUSIONS

Higher BMI and WC were independently associated with lower GFR (long term) after living kidney donation.

Association of anthropometric measures with all-cause and cause-specific mortality in US adults: revisiting the obesity paradox

OBJECTIVE

Previous studies have shown that the obesity paradox exists in a variety of clinical settings, whereby obese individuals have lower mortality than their normal-weight counterparts. It remains unclear whether the association between obesity and mortality risk varies by anthropometric measures. The purpose of this study is to examine the association between various anthropometric measures and all-cause and cause-specific mortality in US adults.

METHODS

This cohort study included data from the National Health and Nutrition Examination Survey between 2009 and 2018, with a sample size of 28,353 individuals weighted to represent 231 million US adults. Anthropometric measurements were obtained by trained technicians using standardized methods. Mortality data were collected from the date of enrollment through December 31, 2019. Weighted Cox proportional hazards models, restricted cubic spline curves, and cumulative incidence analyses were performed.

RESULTS

A total of 2091 all-cause deaths, 606 cardiovascular deaths, 519 cancer deaths, and 966 other-cause deaths occurred during a median follow-up of 5.9 years. The association between body mass index (BMI) and mortality risk was inversely J-shaped, whereas the association between waist-to-height ratio (WHtR) and mortality risk was positively J-shaped. There was a progressive increase in the association between the WHtR category and mortality risk. Compared with the reference category of WHtR < 0.5, the estimated hazard ratio (HR) for all-cause mortality was 1.004 (95% confidence interval [CI] 1.001-1.006) for WHtR 0.50-0.59, 1.123 (95% CI 1.120-1.127) for WHtR 0.60-0.69, 1.591 (95% CI 1.584-1.598) for WHtR 0.70-0.79, and 2.214 (95% CI 2.200-2.228) for WHtR ≥ 0.8, respectively. Other anthropometric indices reflecting central obesity also showed that greater adiposity was associated with higher mortality.

CONCLUSIONS

Anthropometric measures reflecting central obesity were independently and positively associated with mortality risk, eliminating the possibility of an obesity paradox.

An Evaluation of Renal Sinus Fat Accumulation Using the Anteroposterior Diameter of the Renal Sinus on a Computed Tomography Axial Image

Backgrounds and objectives Renal sinus fat (RSF) is an indicator of obesity-related complications. However, the measurement and imaging process are complicated. For a simple measurement of RSF, we focused on the kidney's shape change caused by RSF accumulation. Thus, this study aimed to investigate whether the anteroposterior diameter of the renal sinus (APDRS) on a computed tomography (CT) axial image is useful for evaluating RSF accumulation. Materials and methods The correlation between APDRS and RSF was investigated in 98 outpatients who underwent abdominal CT. In addition, the correlation between APDRS or RSF and obesity indicators (estimated glomerular filtration rate from serum creatinine levels (eGFRcreat), body mass index (BMI), and visceral adipose tissue (VAT)) was also investigated. We classified patients based on the presence or absence of at least one underlying disease (chronic kidney disease (CKD), cardiovascular diseases (CVD), hypertension, and type 2 diabetes (T2D)) and investigated significant differences between the two groups at APDRS and RSF. The intraclass correlation coefficient (ICC) was also calculated for APDRS. Results There was a strong positive correlation between RSF and APDRS (r = 0.802, P < 0.01). The obesity indicators (eGFRcreat, BMI, and VAT) were correlated with RSF and APDRS (P < 0.01). Out of 98 outpatients, 48 had at least one underlying disease. There were statistically significant differences in APDRS and RSF between the patients with and without at least one of the underlying diseases caused by obesity (P < 0.01). The inter-reader ICC for the measurement of the APDRS was 0.98. Conclusions APDRS on a CT axial image may be useful for the evaluation of RSF accumulation.

Impact of obesity on intensive care unit outcomes in older patients with critical illness: A cohort study

BACKGROUND

Although the paradoxical association between obesity and improved survival has been reported in a variety of clinical settings, its applicability to intensive care unit (ICU) outcomes in older critically ill patients remains unclear. We sought to examine the association between obesity and 30-day mortality and other adverse outcomes in this population.

METHODS

We analyzed data of older patients (≥ 60 years) in the eICU Collaborative Research Database. Body mass index (BMI) was stratified according to the World Health Organization obesity classification. Logistic regression model was used to estimate adjusted odds ratios (ORs), and cubic spline curve was used to explore the nonlinear association between BMI and 30-day ICU outcomes. Stratified analysis and sensitivity analysis were also performed.

RESULTS

Compared with class I obesity, under- and normal-weight were associated with higher all-cause, cardiovascular and noncardiovascular mortality, and class III obesity was associated with greater all-cause and cardiovascular mortality (OR, 1.18 [95% CI, 1.06-1.32], 1.28 [1.08-1.51]). Obesity classes II and III were associated with higher composite all-cause mortality, mechanical ventilation, or vasoactive drug usage risks (OR, 1.12 [95% CI, 1.04-1.20], 1.33 [1.24-1.43]). Mechanical ventilation was strongly positively associated with BMI. A significant BMI-by-sex interaction was observed for cardiovascular mortality, such that the association between severe obesity and mortality was more pronounced among older men than older women.

CONCLUSIONS

The obesity paradox does not appear to apply to short-term ICU outcomes in older patients with critical illness, mainly due to increased all-cause and cardiovascular mortality in severely obese patients, particularly in men.

Impact of body mass index on adverse kidney events in diabetes mellitus patients: A systematic-review and meta-analysis

BACKGROUND

The incidence of chronic kidney disease among patients with diabetes mellitus (DM) remains a global concern. Long-term obesity is known to possibly influence the development of type 2 diabetes mellitus. However, no previous meta-analysis has assessed the effects of body mass index (BMI) on adverse kidney events in patients with DM.

AIM

To determine the impact of BMI on adverse kidney events in patients with DM.

METHODS

A systematic literature search was performed on the PubMed, ISI Web of Science, Scopus, Ovid, Google Scholar, EMBASE, and BMJ databases. We included trials with the following characteristics: (1) Type of study: Prospective, retrospective, randomized, and non-randomized in design; (2) participants: Restricted to patients with DM aged ≥ 18 years; (3) intervention: No intervention; and (4) kidney adverse events: Onset of diabetic kidney disease [estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73 m2 and/or microalbuminuria value of ≥ 30 mg/g Cr], serum creatinine increase of more than double the baseline or end-stage renal disease (eGFR < 15 mL/min/1.73 m2 or dialysis), or death.

RESULTS

Overall, 11 studies involving 801 patients with DM were included. High BMI (≥ 25 kg/m2) was significantly associated with higher blood pressure (BP) [systolic BP by 0.20, 95% confidence interval (CI): 0.15-0.25, P < 0.00001; diastolic BP by 0.21 mmHg, 95%CI: 0.04-0.37, P = 0.010], serum albumin, triglycerides [standard mean difference (SMD) = 0.35, 95%CI: 0.29-0.41, P < 0.00001], low-density lipoprotein (SMD = 0.12, 95%CI: 0.04-0.20, P = 0.030), and lower high-density lipoprotein (SMD = -0.36, 95%CI: -0.51 to -0.21, P < 0.00001) in patients with DM compared with those with low BMIs (< 25 kg/m2). Our analysis showed that high BMI was associated with a higher risk ratio of adverse kidney events than low BMI (RR: 1.22, 95%CI: 1.01-1.43, P = 0.036).

CONCLUSION

The present analysis suggested that high BMI was a risk factor for adverse kidney events in patients with DM.

Comprehensive analysis of the relationship between xanthine oxidoreductase activity and chronic kidney disease

Chronic kidney disease (CKD) is a common disease that seriously endangers human health. However, the potential relationship between xanthine oxidoreductase (XOR) activity and CKD remains unclear. In this study, we used clinical data, CKD datasets from the Gene Expression Omnibus database, and untargeted metabolomics to explain the relationship between XOR activity and CKD. First, XOR activity showed high correlation with the biomarkers of CKD, such as serum creatinine, blood urea nitrogen, uric acid, and estimated glomerular filtration rate. Then, we used least absolute shrinkage and selection operator logical regression algorithm and random forest algorithm to screen CKD molecular markers from differentially expressed genes, and the results of qRT-PCR of XDH, KOX-1, and ROMO1 were in accordance with the results of bioinformatics analyses. In addition, untargeted metabolomics analysis revealed that the purine metabolism pathway was significantly enriched in CKD patients in the simulated models of kidney fibrosis.

The Triglyceride-Glucose Index is Independently Associated with Chronic Kidney Disease in the Geriatric Population, Regardless of Obesity and Sex

BACKGROUND

Insulin resistance (IR) negatively affects several risk factors of chronic kidney disease (CKD). This cross-sectional study investigated whether the triglyceride-glucose (TyG) index, which reflects IR, was independently associated with CKD in a geriatric population, regardless of obesity and sex.

METHODS

The analysis included 7,326 individuals (2,864 males and 4,462 females) aged ≥60 years. Non-obesity or obesity was evaluated using a body mass index cutoff of 25 kg/m2. The TyG index was calculated as ln [triglyceride concentration (mg/dL)×fasting plasma glucose concentration (mg/dL)]/2. All participants were categorized into three groups according to TyG tertiles. Moderate-to-severe CKD (MSCKD) was defined as an estimated glomerular filtration rate (eGFR) of <45.0 mL/min/1.73 m2.

RESULTS

In males and females with or without obesity, a trend test showed a decreasing tendency in the eGFR from the lowest to highest TyG tertiles. Males without obesity and females with obesity in the middle and highest tertiles of the TyG index were 2.342 and 2.393, and were 2.313 and 3.516 times more likely to have MSCKD, respectively. Those with or without obesity in the highest tertile of the TyG index were 1.736 and 2.374 times more likely to have MSCKD, respectively.

CONCLUSION

Geriatric populations with an increased TyG index have a high risk of MSCKD regardless of obesity and sex. Our findings suggest that increased IR is associated with CKD in the geriatric population independent of obesity and sex.

Risk Factors for Incident CKD in Black and White Americans: The REGARDS Study

RATIONALE & OBJECTIVE

Little information exists on the incidence of and risk factors for chronic kidney disease (CKD) in contemporary US cohorts and whether risk factors differ by race, sex, or region in the United States.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

4,198 Black and 7,799 White participants aged at least 45 years, recruited from 2003 through 2007 across the continental United States, with baseline estimated glomerular filtration rate (eGFR)>60mL/min/1.73m2 and eGFR assessed again approximately 9 years later.

EXPOSURES

Age, sex, race (Black or White), region ("stroke belt" or other), education, income, systolic blood pressure, body mass index, diabetes, coronary heart disease, hyperlipidemia, smoking, and albuminuria.

OUTCOMES

(1) eGFR change and (2) incident CKD defined as eGFR<60mL/min/1.73m2 and≥40% decrease from baseline or kidney failure.

ANALYTICAL APPROACH

Linear regression and modified Poisson regression were used to determine the association of risk factors with eGFR change and incident CKD overall and stratified by race, sex, and region.

RESULTS

Mean age of participants was 63±8 (SD) years, 54% were female, and 35% were Black. After 9.4±1.0 years of follow-up, CKD developed in 9%. In an age-, sex-, and race-adjusted model, Black race (β =-0.13; P<0.001) was associated with higher risk of eGFR change, but this was attenuated in the fully adjusted model (β=0.02; P=0.5). Stroke belt residence was independently associated with eGFR change (β =-0.10; P<0.001) and incident CKD (relative risk, 1.14 [95% CI, 1.01-1.30]). Albuminuria was more strongly associated with eGFR change (β of-0.26 vs-0.17; P=0.01 for interaction) in Black compared with White participants. Results were similar for incident CKD.

LIMITATIONS

Persons of Hispanic ethnicity were excluded; unknown duration and/or severity of risk factors.

CONCLUSIONS

Established CKD risk factors accounted for higher risk of incident CKD in Black versus White individuals. Albuminuria was a stronger risk factor for eGFR decrease and incident CKD in Black compared with White individuals. Living in the US stroke belt is a novel risk factor for CKD.

An investigation of low-protein diets' qualification rates and an analysis of their short-term effects for patients with CKD stages 3-5: a single-center retrospective cohort study from China

BACKGROUND

The feasibility and efficacy of low-protein diets (LPD) treatment in chronic kidney disease (CKD) is controversial. Based on the characteristics of the Chinese diet, we observe the qualification rates and short-term clinical effects of LPD for CKD patients in our center.

METHODS

This is a retrospective cohort study. CKD stages 3-5 patients who were regularly followed up 5 times (over 2 years) and treated with LPD were included. We collected clinical data to observe the changes in LPD qualification rates and divided patients into LPD and non-LPD group according to the average dietary protein intake (DPI) of 5 follow-up time points and compared the changes in primary and secondary outcome measures between the two groups.

RESULTS

We analyzed data from 161 eligible CKD stages 3-5 patients. From baseline to the 5th follow-up time point, the LPD qualification rates of all patients were 11.80%, 35.40%, 47.82%, 53.43% and 54.04%, respectively. For primary outcome measures, the urine protein/creatinine ratio (UPCR) decreased more in the LPD group than in the non-LPD group [Median (interquartile range, IQR) of the difference between the 5th follow-up time point and baseline: 0.19 (- 0.01-0.73) vs. 0.10 (- 0.08-0.27), P < 0.001]. We constructed three classes of mixed linear models (model I, II, III). The UPCR slopes were all negative in the LPD group and positive in the non-LPD group (P < 0.001). Meanwhile, in model I, the estimate glomerular filtration rate(eGFR) decline slope in the LPD group was lower than that in the non-LPD group [slope (standard error): - 1.32 (0.37) vs. - 2.35 (0.33), P = 0.036]. For secondary outcome measures, body mass index (BMI) triglycerides (TG), body weight, and fat free mass (FFM) showed stable statistical differences in the comparison of LPD and non-LPD groups, with greater declines in the former.

CONCLUSION

The results of this study suggest that LPD treatment can reduce UPCR in patients with CKD stages 3-5, and may also delay the decline in eGFR. Meanwhile, it also reduces BMI, TG, body weight, and FFM, thus the need to prevent malnutrition in clinical implementation.

Relación entre sobrepeso y obesidad con la progresión de la enfermedad renal crónica en pacientes del Centro Médico Naval en México

Introducción: La progresión de la enfermedad renal crónica podría estar asociada directa o indirectamente al sobrepeso y la obesidad; sin embargo, hasta el momento no hay evidencias suficientes para constatar esta relación. Objetivo: Determinar si el sobrepeso y obesidad son factores que contribuyen a una progresión más acelerada de la enfermedad renal crónica en una muestra de pacientes del Centro Médico Naval. Material y Método: A través de un estudio cuantitativo y observacional, de tipo comparativo, longitudinal y retrospectivo, se determinaron los cambios en el normopeso, sobrepeso y obesidad en 44 pacientes. La progresión de la enfermedad renal crónica se determinó con base en la tasa de filtración glomerular y niveles de albuminuria que presentaron estos pacientes. Los datos se recabaron con un instrumento de registro de diseño propio, durante un seguimiento de 3 años que se llevó a cabo de enero de 2019 a diciembre de 2021. Resultados: Los resultados muestran una tendencia al aumento en la progresión de la enfermedad renal crónica. Conclusiones: A pesar de que se encontró una tendencia al aumento, no se pudo probar una asociación estadísticamente significativa entre la obesidad y el sobrepeso con la progresión de esta enfermedad.

Relación entre sobrepeso y obesidad con la progresión de la enfermedad renal crónica en pacientes del Centro Médico Naval en México

Introducción: La progresión de la enfermedad renal crónica podría estar asociada directa o indirectamente al sobrepeso y la obesidad; sin embargo, hasta el momento no hay evidencias suficientes para constatar esta relación. Objetivo: Determinar si el sobrepeso y obesidad son factores que contribuyen a una progresión más acelerada de la enfermedad renal crónica en una muestra de pacientes del Centro Médico Naval. Material y Método: A través de un estudio cuantitativo y observacional, de tipo comparativo, longitudinal y retrospectivo, se determinaron los cambios en el normopeso, sobrepeso y obesidad en 44 pacientes. La progresión de la enfermedad renal crónica se determinó con base en la tasa de filtración glomerular y niveles de albuminuria que presentaron estos pacientes. Los datos se recabaron con un instrumento de registro de diseño propio, durante un seguimiento de 3 años que se llevó a cabo de enero de 2019 a diciembre de 2021. Resultados: Los resultados muestran una tendencia al aumento en la progresión de la enfermedad renal crónica. Conclusiones: A pesar de que se encontró una tendencia al aumento, no se pudo probar una asociación estadísticamente significativa entre la obesidad y el sobrepeso con la progresión de esta enfermedad.

Association of intraabdominal fat with the risk of incident chronic kidney disease according to body mass index among Korean adults

BACKGROUND

The association between abdominal visceral adipose tissue and the risk of incident chronic kidney disease according to body mass index in the Asian population, remains unclear. We evaluated the impact of abdominal adiposity stratified by body mass index on the risk of incident chronic kidney disease.

METHODS

A cohort study included 11,050 adult participants who underwent health check-ups and re-evaluated the follow-up medical examination at a single university-affiliated healthcare center. Cross-sectional abdominal adipose tissue areas were measured using computed tomography. The primary outcome was progression to chronic kidney disease (estimated glomerular filtration rate <60 ml/min/1.73m2). The highest quartile of visceral adipose tissue was used for the cut-off of central obesity.

RESULTS

During the mean of 5.6 follow-up years, 104 incident chronic kidney disease cases were identified. The risk for chronic kidney disease incidence was significantly increased in the 3rd and 4th quartile ranges of visceral adipose tissue [hazard ratio (95% confidence interval)]: 4.59 (1.48-14.30) and 7.50 (2.33-24.20), respectively. In the analysis stratified by body mass index, the chronic kidney disease incidence risk was increased in the highest quartile range of visceral adipose tissue in the normal weight group: 7.06 (1.35-37.04). However, there was no significant relationship between visceral adipose tissue and chronic kidney disease in the obese group. Compared to the subjects with normal weight and absent central obesity, the hazard ratio for chronic kidney disease incidence was 2.32 (1.26-4.27) among subjects with normal weight and central obesity and 1.81 (1.03-3.15) among subjects with obesity and central obesity.

CONCLUSION

Visceral adipose tissue was a significant risk factor for subsequent chronic kidney disease progression, and the association was identified only in the normal weight group. Normal-weight central obesity was associated with excess risk of chronic kidney disease, similar to the risk in the group with obesity and central obesity.

Dietary weight loss strategies for kidney stone patients

PURPOSE

Overweight has been associated with an increased risk of incident and recurrent kidney stone disease. Weight reduction is the therapeutic consequence to decrease the risk of stone formation. This review examines the effectiveness of different weight loss strategies on weight reduction and cardiometabolic risk profile, with a particular focus on risk factors for urolithiasis.

METHODS

A selective literature search was performed using PubMed and Cochrane library.

RESULTS

Clinical evidence for the potential benefits of dietary weight loss strategies for kidney stone disease is limited. A conventional, energy-restricted diet may significantly induce weight loss and reduce urinary supersaturation of calcium oxalate in overweight individuals with or without a history of stone formation. The current data indicate that an energy-restricted diet with partial meal replacement may additionally decrease the relative supersaturation of uric acid and further improve the cardiometabolic risk profile, and, thus, may be a favourable option for overweight kidney stone patients. Studies on the Mediterranean and DASH diets on the association between weight loss and the risk of urinary stone formation are lacking.

CONCLUSION

An energy-restricted diet with or without meal replacement could be a promising weight loss strategy for overweight kidney stone patients. Further studies are needed to evaluate the impact of different weight loss strategies on urinary risk factors and cardiometabolic risk profile in urolithiasis.

Impact of obesity on all-cause and cause-specific mortality among critically ill men and women: a cohort study on the eICU database

Background

The effect of obesity on intensive care unit outcomes among critically ill patients and whether there are sex differences have not been well investigated. We sought to determine the association between obesity and 30-day all-cause and cause-specific mortality among critically ill men and women.

Methods

Adult participants who had body mass index (BMI) measurements were included from the eICU database. Participants were divided into six groups according to BMI (kg/m²) categories (underweight, <18.5; normal weight, 18.5-24.9; overweight, 25-29.9; class I obesity, 30-34.9; class II obesity, 35-39.9; class III obesity, ≥40). A multivariable adjusted logistic model was conducted with odds ratios (ORs) and 95% confidence intervals (CIs). A cubic spline curve based on the generalized additive model was used to represent the nonlinear association. Stratified analysis and sensitivity analysis were also performed.

Results

A total of 160,940 individuals were included in the analysis. Compared with the class I obesity category, the underweight and normal weight categories had higher all-cause mortality, and the multivariable adjusted ORs were 1.62 (95% CI: 1.48-1.77) and 1.20 (95% CI: 1.13-1.27) for the general population, 1.76 (95% CI: 1.54-2.01) and 1.22 (95% CI: 1.13-1.32) for men, and 1.51 (95% CI: 1.33-1.71) and 1.16 (95% CI: 1.06-1.27) for women, respectively. Accordingly, multivariable adjusted ORs for the class III obesity category were 1.14 (95% CI: 1.05-1.24) for the general population, 1.18 (95% CI: 1.05-1.33) for men, and 1.10 (95% CI: 0.98-1.23) for women. With cubic spline curves, the association between BMI and all-cause mortality was U-shaped or reverse J-shaped. Similar findings were observed for cause-specific mortality, with the underweight category associated with a higher risk of mortality. Class III obesity increased the risk of cardiovascular death among men (OR 1.51; 95% CI: 1.23-1.84) and increased the risk of other-cause death among women (OR 1.33; 95% CI: 1.10-1.61).

Conclusion

The obesity paradox appears to be suitable for all-cause and cause-specific mortality among critically ill men and women. However, the protective effect of obesity cannot be extended to severely obese individuals. The association between BMI and cardiovascular mortality was sex-specific and was more pronounced among men than among women. Graphical abstract.

Strong Negative Association of non-HDL Cholesterol Goal Achievement With Incident CKD Among Adults With Diabetes

Context

The relative importance of the control of different metabolic risk factors for the prevention of chronic kidney disease among patients with diabetes in real life conditions is insufficiently understood.

Objective

We evaluated the effect of the achievement of glycated hemoglobin A_1c (HbA_1c), systolic blood pressure (SBP), and low-density lipoprotein cholesterol (LDLc) or non-high-density lipoprotein cholesterol (non-HDLc) goals (ABC goals) on the development of incident chronic kidney disease (iCKD) among patients with diabetes.

Methods

In a nationwide registry of all individuals diagnosed with diabetes assisted by the health system in Colombia, we analyzed the association between baseline or sustained goal achievement and development of iCKD over a 4-year follow-up. iCKD was defined as a new occurrence of an estimated glomerular filtration rate less than 60 mL/min/1.73 m², hemodialysis, peritoneal dialysis, or kidney transplant.

Results

The study included 998 790 adults with diabetes (56% female, mean age 59). There were 125 626 cases of iCKD. After adjustment for multiple confounders, a baseline SBP less than 130 mm Hg (odds ratio [OR] 0.79 [0.78-0.80]) and a baseline HbA_1c less than 7.0% (OR 0.86 [0.85-0.87]) were negatively associated with iCKD. Sustained achievement showed stronger negative associations with iCKD than just baseline achievement. Considering each goal separately, sustained non-HDLc less than 130 mg/dL had the strongest negative association with iCKD (OR 0.67 [0.65-0.69]). Patients who maintained the triple ABC goal over the entire follow-up had 32% (29-34) lower odds of developing CKD, 38% (34-42) if they additionally kept a normal body mass index (BMI). Sustained ABC control including a normal BMI was more strongly associated with a lower incidence of CKD in patients of Black race (OR 0.72 vs 0.89; P for interaction = .002).

Conclusion

At the country level, sustained achievement of ABC goals and most especially non-HDLc were associated with substantial reductions in iCKD.

Impact of body mass index on in-hospital mortality in older patients hospitalized for bacterial pneumonia with non-dialysis-dependent chronic kidney disease

BACKGROUND

Low body mass index (BMI) in older individuals with decreased kidney function is important because of its association with poor prognosis and frailty. Herein, we aimed to clarify the association between BMI and in-hospital mortality among older patients with non-dialysis-dependent chronic kidney disease (CKD) stratified by kidney function.

METHODS

Using data from the Medical Vision Database, this multicentre cohort study included people aged ≥ 60 years with an estimated glomerular filtration rate of < 60 ml/min/1.73 m² but without dialysis dependency, hospitalised for bacterial pneumonia during 2014-2019. We compared the risk of in-hospital death between patients with BMI categories based on the quartiles (low, medium-low, medium-high, and high) setting medium-high BMI as a reference. We further assessed the association with BMI using a cubic spline, setting BMI as a nonlinear continuous variable and a BMI of 22 kg/m² as a reference. We also evaluated the association between BMI and kidney function using a generalised additive model adjusted for interaction terms between nonlinear continuous BMI and kidney function.

RESULTS

We obtained data for 3,952 patients, with 350 (8.9%) in-hospital deaths. When compared with medium-high BMI, low BMI was associated with an increased risk of death and longer hospital stay, whereas the other two categories were comparable. Models using a cubic spline showing an association between BMI and in-hospital death showed an L-shaped curve; BMI < 22.0 kg/m² was associated with an increased risk for mortality, and at a BMI of 18.5 kg/m², the odds ratio was 1.43 with a 95% confidence interval of 1.26-1.61 when compared with a BMI of 22.0 kg/m². Analysis of the interactive effects of kidney function using the generalised additive model showed that a protective association of high BMI tapered along with decreased kidney function.

CONCLUSIONS

This cohort study suggests not only that lower BMI and low kidney function are associated with in-hospital mortality independently but also that the protective effects of high BMI weaken as kidney function decreases via the analysis of the interaction terms. This study highlights the necessity for the prevention of underweight and demonstrates the interaction between BMI and kidney function in older patients with non-dialysis-dependent CKD.

[Nephrological management and drug dosing in patients with rheumatic diseases and renal insufficiency]

BACKGROUND

In patients with inflammatory rheumatic diseases and renal insufficiency there are two challenges for physicians: to adapt the antirheumatic medication to the renal function and to carry out a nephroprotective treatment that prevents long-term deterioration of renal function and reduces the elevated cardiovascular risk.

METHODS

A literature search (in PubMed) was carried out and the current state of knowledge on nephroprotective treatment strategies and the treatment of rheumatic diseases in the presence of renal insufficiency was collated, evaluated and summarized.

RESULTS

Lifestyle interventions, especially the cessation of smoking and drug treatment strategies form the basis of nephroprotection including the control of diabetes mellitus with metformin, sodium glucose transporter 2 (SGLT2) inhibitors, glucagon-like peptide 1 (GLP1) analogues and control of hypertension with blockade of the renin-angiotensin-aldosterone system (RAAS), hyperlipidemia, hyperphosphatemia and metabolic acidosis. The SGLT2 inhibitors are also effective for nondiabetic nephropathy. The elevated cardiovascular risk is further reduced by effective control of inflammatory rheumatic activity. Numerous conventional disease modifying antirheumatic drugs, especially methotrexate and the Janus kinase (JAK) inhibitors baricitinib and filgotinib, must mostly be adapted to the renal function. In contrast, biologics can be given in standard doses with the exception of anakinra. The increased cardiovascular risk currently limits the use of tofacitinib in patients with renal insufficiency.

CONCLUSION

The antirheumatic medication should be modified and a complex nephroprotective treatment concept is mandatory in the management of patients with rheumatic disease and renal insufficiency, that in the best-case scenario can be guaranteed by a close interdisciplinary cooperation of rheumatologists and nephrologists.

Chronic Sub-Clinical Systemic Metabolic Acidosis - A Review with Implications for Clinical Practice

When arterial serum pH remains near the lower pH limit of 7.35 for protracted periods of time, a low-grade, sub-clinical form of acidosis results, referred to in this review as chronic, sub-clinical, systemic metabolic acidosis (CSSMA). This narrative review explores the scientific basis for CSSMA, its consequences for health, and potential therapeutic interventions. The major etiology of CSSMA is the shift away from the ancestral, alkaline diet which was rich in fruit and vegetables, toward the contemporary, acidogenic 'Westernized' diet characterized by higher animal protein consumption and lack of base forming minerals. Urine pH is reduced with high dietary acid load and may be a convenient marker of CSSMA. Evidence suggests further that CSSMA negatively influences cortisol levels potentially contributing significantly to the pathophysiology thereof. Both CSSMA and high dietary acid load are associated with the risk and prognosis of various chronic diseases. Clinical trials show that CSSMA can be addressed successfully through alkalizing the diet by increasing fruit and vegetable intake and/or supplementing with alkaline minerals. This review confirms the existence of a significant body of evidence regarding this low-grade form of acidosis as well as evidence to support its diverse negative implications for health, and concludes that CSSMA is a condition warranting further research.

Fatty liver disease reverses the obesity paradox in chronic kidney disease stages 3-5: A follow-up study of NHANES III

High body mass index (BMI) has been associated with better survival in patients with end-stage kidney disease. Individuals with fatty liver disease (FLD) have a higher risk of chronic kidney disease. It remains unclear whether the survival benefit of high BMI in patients with chronic kidney disease is present when there is concomitant FLD. This study used the data set from the Third American National Health and Nutrition Examination Survey and the corresponding survival data. The Cox proportional hazards model was used to evaluate the effect of BMI on mortality. A total of 12,445 participants were included. The prevalence of FLD was 39.8%. The median follow-up time (with interquartile range) was 22.8 (20.8-24.8) years. During this period, 3749 (30.1%, 14.4 of 1000 person-year) deaths were observed. Among these, 1169 (31.2%) died within the first 10 years. The Cox regression analysis showed that the BMI level was not associated with 25-year mortality in patients with decreased glomerular filtration rate (GFR < 60 ml/min/1.73 m2 ), but 10-year mortality was significantly lower in patients with BMI ≥ 25 kg/m2 than in those with BMI < 25 kg/m2 (p = 0.049). Multivariate analysis showed BMI ≥ 25 kg/m2 was an independent protective factor for 10-year mortality (hazard ratio [HR] 0.691, 95% confidence interval [CI] 0.559-0.856; p = 0.001). This protective effect of higher BMI was lost in patients with FLD (HR 0.884, 95% CI 0.585-1.335; p = 0.557) but persisted in the non-FLD group (HR 0.625, 95% CI 0.479-0.816; p = 0.001). The survival benefit of overweight/obesity for patients with decreased GFR, which was attenuated by the presence of FLD, only existed in the first decade.

Use of the Visceral Adiposity Index as an Indicator of Chronic Kidney Disease in Older Adults: Comparison with Body Mass Index

The visceral adiposity index (VAI) was recently introduced to quantify visceral fat accumulation and dysfunction. This cross-sectional study explored whether the VAI is associated with chronic kidney disease (CKD) in older adults and compared its utility with that of body mass index (BMI) for predicting CKD. In total, 7736 older adults (3479 men and 4257 women) aged ≥ 60 years were divided into normal, mild, and moderate-to-severe CKD groups. Associations of the VAI and BMI with CKD were compared among the groups, and cut-off points for moderate-to-severe CKD (MSCKD) were established. While the VAI could discriminate among all of the groups, the BMI could not. The severity of CKD was more strongly associated with the VAI than BMI. The odds ratios indicated that, in the fully adjusted model, the VAI was a significant predictor of MSCKD in both men and women, while the BMI was a significant predictor only in men. For the VAI, the area under the receiver operating characteristic curve values for men and women were 0.631 (cut-off point: ≥2.993) and 0.588 (≥4.001), compared with 0.555 (≥25.335) and 0.533 (≥24.096) for BMI, respectively. Taken together, the findings suggest that the VAI is associated with CKD and represents a better indicator for the disease than BMI.

The Beneficial Effects of Bariatric-Surgery-Induced Weight Loss on Renal Function

Obesity represents an independent risk factor for the development of chronic kidney disease (CKD), leading to specific histopathological alterations, known as obesity-related glomerulopathy. Bariatric surgery is the most effective means of inducing and maintaining sustained weight loss. Furthermore, in the context of bariatric-surgery-induced weight loss, a reduction in the proinflammatory state and an improvement in the adipokine profile occur, which may also contribute to the improvement of renal function following bariatric surgery. However, the assessment of renal function in the context of obesity and following marked weight loss is difficult, since the formulas adopted to estimate glomerular function use biomarkers whose production is dependent on muscle mass (creatinine) or adipose tissue mass and inflammation (cystatin-c). Thus, following bariatric surgery, the extent to which reductions in plasma concentrations reflect the actual improvement in renal function is not clear. Despite this limitation, the available literature suggests that in patients with hyperfiltration at baseline, GFR is reduced following bariatric surgery, whereas GFR is increased in patients with decreased GFR at baseline. These findings are also confirmed in the few studies that have used measured rather than estimated GFR. Albuminuria is also decreased following bariatric surgery. Moreover, bariatric surgery seems superior in achieving the remission of albuminuria and early CKD than the best medical treatment. In this article, we discuss the pathophysiology of renal complications in obesity, review the mechanisms through which weight loss induces improvements in renal function, and provide an overview of the renal outcomes following bariatric surgery.

Multidisciplinary residential program for the treatment of obesity: how body composition assessed by DXA and blood chemistry parameters change during hospitalization and which variations in body composition occur from discharge up to 1-year follow-up

PURPOSE

Obesity is a chronic disease characterized by a complex variable clinical presentation with comorbidities. A multidisciplinary residential program (MRP) represents one of the best options for treating obesity. The purpose of this study was to evaluate the effectiveness of 8-week MRP on weight loss, body composition assessed by DXA, and metabolic blood parameters between entry (T0) and discharge (T1). The secondary endpoint was the evaluation of the patients' adherence to diet during the check-up outpatient visits, at 2 (T2), 6 (T3), and 12 (T4) months after discharge.

METHODS

168 subjects were enrolled (61 males and 117 females, aged 58.5 ± 13 years, BMI 41.3 ± 6 kg/m²) in the study. The difference in values ​​(end of hospitalization compared to baseline) was calculated through the univariate analysis procedure, which provides regression analysis and analysis of variance for a variable dependent on one or more variables.

RESULTS

There was a statistically significant improvement of all parameters investigated: total mass (- 5.68 kg), fat mass (- 4416.85 g), fat mass index (- 1724.56), visceral adipose tissue (- 332.76 g), arm circumference (- 1.63 cm) and calf circumference (- 1.16 cm). As it is reasonable to expect, even the fat free mass has been reduced (- 1236.03 g); however, the skeletal muscle index was not affected. Statistically significant improvement in glycaemic and lipid profile were reported. The BMI average reduction continued from discharge until T4. No statistically significant changes in fat free mass and visceral adipose tissue (VAT) were reported during a year of follow-up.

CONCLUSIONS

The present study demonstrated the clinical benefits of 8-week MRP, which includes hypocaloric diet, physical exercise, and psychological support.

LEVEL OF EVIDENCE

III, evidence obtained from cohort or case-control analytic studies.

Lifestyle-Related Risk Factors for the Incidence and Progression of Chronic Kidney Disease in the Healthy Young and Middle-Aged Population

The prevalence of chronic kidney disease (CKD) increased by 88% from 1990 to 2016. Age of onset of lifestyle-related diseases (such as hypertension, diabetes mellitus, obesity, dyslipidemia, and hyperuricemia), which are risk factors for incident CKD, is lower now compared with the past. Thus, we aimed to evaluate the risk factors for the incidence and progression of CKD in the young and middle-aged population. There are differences in the risk for CKD among the young, middle-aged, and elderly populations. We aimed to assess obesity (which is basic component of metabolic syndrome), waist circumference, and abdominal adiposity, which are predictive factors of CKD in the younger population. Furthermore, we described the management and clinical evidence of hypertension, diabetes mellitus, dyslipidemia, and hyperuricemia for young and middle-aged patients, along with diet management and nutrients associated with kidney function. Kidney function in the young and middle-aged population is mostly normal, and they are considered a low-risk group for incident CKD. Thus, we expect this review to be useful in reducing the prevalence of CKD.

Metabolic Syndrome and Obesity-Related Indices Are Associated with Rapid Renal Function Decline in a Large Taiwanese Population Follow-Up Study

A rapid decline in renal function can cause many complications, and therefore it is important to detect associated risk factors. Few studies have evaluated the associations among obesity-related indices and metabolic syndrome (MetS) with renal function decline. This longitudinal study aimed to explore these relationships in a large cohort of Taiwanese participants. The studied obesity-related indices were waist-to-height ratio (WHtR), A body shape index (ABSI), visceral adiposity index (VAI), lipid accumulation product (LAP), waist-to-hip ratio (WHR), body roundness index (BRI), conicity index (CI), body mass index (BMI), body adiposity index (BAI) and abdominal volume index (AVI). We included 122,068 participants in the baseline study, of whom 27,033 were followed for a median of four years. The baseline prevalence of MetS was 17.7%. Multivariable analysis showed that the participants with MetS and high VAI, WHtR, WHR, LAP, CI, BRI, BMI, BAI, AVI, and ABSI values were significantly associated with a high baseline estimated glomerular filtration rate (eGFR) (all p < 0.001). In addition, the participants with MetS (p < 0.001), high WHtR (p = 0.007), low LAP (p < 0.001), high BRI (p = 0.002), high CI (p = 0.002), high AVI (p = 0.001), high VAI (p = 0.017), and high ABSI (p = 0.013) were significantly associated with a low △eGFR, indicating a rapid decline in renal function. These results showed associations between MetS and high values of obesity-related indices except LAP with high baseline eGFR and rapid decline in kidney function. These findings suggest that screening for MetS and obesity may help to slow the decline in renal function in high-risk populations.

Association of Longitudinal Trajectories of Insulin Resistance With Adverse Renal Outcomes

OBJECTIVE

To analyze the relationship between time-serial changes in insulin resistance and renal outcomes.

RESEARCH DESIGN AND METHODS

A prospective cohort of subjects from the general population without chronic kidney disease (CKD) underwent a biennial checkup for 12 years (n = 5,347). The 12-year duration was divided into a 6-year exposure period, where distinct HOMA for insulin resistance (HOMA-IR) trajectories were identified using latent variable mixture modeling, followed by a 6-year event accrual period, from which the renal outcome data were analyzed. The primary end point was adverse renal outcomes, defined as a composite of estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 in two or more consecutive checkups or albumin ≥1+ on urine strip.

RESULTS

Two distinct groups of HOMA-IR trajectories were identified during the exposure period: stable (n = 4,770) and increasing (n = 577). During the event accrual period, 449 patients (8.4%) developed adverse renal outcomes, and the risk was higher in the increasing HOMA-IR trajectory group than in the stable group (hazard ratio 2.06, 95% CI 1.62-2.60, P < 0.001). The results were similar after adjustment for baseline clinical characteristics, comorbidities, anthropometric and laboratory findings, eGFR, and HOMA-IR. The clinical significance of increasing HOMA-IR trajectory was similar in three or four HOMA-IR trajectories. The increasing tendency of HOMA-IR was persistently associated with a higher incidence of adverse renal outcomes, irrespective of the prevalence of diabetes.

CONCLUSIONS

An increasing tendency of insulin resistance was associated with a higher risk of adverse renal outcomes. Time-serial tracking of insulin resistance may help identify patients at high risk for CKD.

Obesity, Weight Loss, Lifestyle Interventions, and Autosomal Dominant Polycystic Kidney Disease

Obesity remains a growing public health concern in industrialized countries around the world. The prevalence of obesity has also continued to rise in those with chronic kidney disease. Epidemiological data suggests those with overweight and obesity, measured by body mass index, have an increased risk for rapid kidney disease progression. Autosomal dominant polycystic kidney disease causes growth and proliferation of kidney cysts resulting in a reduction in kidney function in the majority of adults. An accumulation of adipose tissue may further exacerbate the metabolic defects that have been associated with ADPKD by affecting various cell signaling pathways. Lifestyle interventions inducing weight loss might help delay disease progression by reducing adipose tissue and systematic inflammation. Further research is needed to determine the mechanistic influence of adipose tissue on disease progression.

A longitudinal examination of objective neighborhood walkability, body mass index, and waist circumference: the REasons for Geographic And Racial Differences in Stroke study

Background

Studies have shown neighborhood walkability is associated with obesity. To advance this research, study designs involving longer follow-up, broader geographic regions, appropriate neighborhood characterization, assessment of exposure length and severity, and consideration of stayers and movers are needed. Using a cohort spanning the conterminous United States, this study examines the longitudinal relationship between a network buffer-derived, duration-weighted neighborhood walkability measure and two adiposity-related outcomes.

Methods

This study included 12,846 Black/African American and White adults in the REasons for Geographic And Racial Differences in Stroke study. Body mass index (BMI) and waist circumference (WC) were assessed at baseline and up to 13.3 years later (M (SD) = 9.4 (1.0) years). BMI and WC were dichotomized. Walk Score® was duration-weighted based on time at each address and categorized as Very Car-Dependent, Car-Dependent, Somewhat Walkable, Very Walkable, and Walker’s Paradise. Unadjusted and adjusted logistic regression models tested each neighborhood walkability-adiposity association. Adjusted models controlled for demographics, health factors, neighborhood socioeconomic status, follow-up time, and either baseline BMI or baseline WC. Adjusted models also tested for interactions. Post-estimation Wald tests examined whether categorical variables had coefficients jointly equal to zero. Orthogonal polynomial contrasts tested for a linear trend in the neighborhood walkability-adiposity relationships.

Results

The odds of being overweight/obese at follow-up were lower for residents with duration-weighted Walk Score® values in the Walker’s Paradise range and residents with values in the Very Walkable range compared to residents with values in the Very Car-Dependent range. Residents with duration-weighted Walk Score® values classified as Very Walkable had significantly lower odds of having a moderate-to-high risk WC at follow-up relative to those in the Very Car-Dependent range. For both outcomes, the effects were small but meaningful. The negative linear trend was significant for BMI but not WC.

Conclusion

People with cumulative neighborhood walkability scores in the Walker’s Paradise range were less likely to be overweight/obese independent of other factors, while people with scores in the Very Walkable range were less likely to be overweight/obese and less likely to have a moderate-to-high risk WC. Addressing neighborhood walkability is one approach to combating obesity.

Impact of Obesity in Kidney Diseases

The clinical consequences of obesity on the kidneys, with or without metabolic abnormalities, involve both renal function and structures. The mechanisms linking obesity and renal damage are well understood, including several effector mechanisms with interconnected pathways. Higher prevalence of urinary albumin excretion, sub-nephrotic syndrome, nephrolithiasis, increased risk of developing CKD, and progression to ESKD have been identified as being associated with obesity and having a relevant clinical impact. Moreover, renal replacement therapy and kidney transplantation are also influenced by obesity. Losing weight is key in limiting the impact that obesity produces on the kidneys by reducing albuminuria/proteinuria, declining rate of eGFR deterioration, delaying the development of CKD and ESKD, and improving the outcome of a renal transplant. Weight reduction may also contribute to appropriate control of cardiometabolic risk factors such as hypertension, metabolic syndrome, diabetes, and dyslipidemia which may be protective not only in renal damage but also cardiovascular disease. Lifestyle changes, some drugs, and bariatric surgery have demonstrated the benefits.

Association between Body Mass Index and Chronic Kidney Disease in Asian Populations: A Participant-level Meta-Analysis

Obesity and chronic kidney disease (CKD) are major public health problems worldwide. However, the association between body mass index (BMI) and CKD is inconclusive in Asians. In this meta-analysis, eight population-based studies, from China, India, Russia (Asian), Singapore and South Korea, provided individual-level data (n=50037). CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². BMI was analyzed both as a continuous variable and in three categories: <25kg/m², normal; 25-29.9kg/m², overweight; and ≥30kg/m², obese. The association between BMI and CKD was evaluated in each study using multivariable logistic regression models and individual estimates were pooled using random-effect meta-analysis to obtain the pooled odds ratio (OR) and 95% confidence interval (CI). Associations were also evaluated in subgroups of age, gender, smoking, diabetes, and hypertension status. Of 50037 adults, 4258 (8.5%) had CKD. 13328 (26.6%) individuals were overweight while 4440 (8.9%) were obese. The prevalence of any CKD ranged from 3.5% to 29.1% across studies. In pooled analysis, both overweight and obesity were associated with increased odds of CKD, with pooled OR (95% CI) of 1.15 (1.03-1.29) and 1.23 (1.06-1.42), respectively. In subgroup analyses, significant associations between BMI and CKD were observed in adult males, non-smokers, and those with diabetes and arterial hypertension (all p<0.05). When evaluated as a continuous variable, BMI was not significantly associated with CKD. If confirmed in longitudinal studies, these results may have clinical implications in risk stratification and preventive measures, given that obesity and CKD are two major chronic diseases with substantial public health burden worldwide.

Obesity Management and Chronic Kidney Disease

Obesity is one of the risk factors for the development and progression of chronic kidney disease (CKD). Several studies have shown the association between increased body mass index and kidney function decline. Obesity leads to CKD directly by acting as an independent risk factor and indirectly through increasing risks for diabetes, hypertension, and atherosclerosis, a group of well-established independent risk factors for CKD. Alterations in renal hemodynamics, inflammation, and in hormones and growth factors results in hyperfiltration injury and focal segmental glomerulosclerosis. In recent years, many studies have shown that the gut microbiome may play a role in the pathogenesis of obesity. Dysbiosis has been noted in obese subjects in both human and animal studies. Changes in the gut microbiome in obese patients promote weight gain by effectively extracting energy from diet, and induction of low-grade inflammation. Evidence also points to the role of inflammation within the adipose tissue in obesity as a key factor in the pathogenesis of obesity-related complications. Thus, obesity is the net result of complex interactions between behavioral, genetic, and environmental factors. In terms of management, conservative approaches are often the first option, but they often are unsuccessful in achieving and/or maintaining weight loss, particularly in severe obesity. Consequently, nonmedical management with bariatric surgery is the most effective treatment option for morbid obesity and has shown mitigation of multiple risk factors for the progression of CKD. The most frequently performed interventions are vertical sleeve gastrectomy and Roux-en-Y gastric bypass. Studies have shown that bariatric surgery is associated with beneficial effects on CKD by mitigating its risk factors by weight loss, reducing insulin resistance, hemoglobin A1c, and proteinuria, in addition to positive long-term outcomes. Because of the epidemic of obesity, the prevalence of obesity in kidney transplant recipients also is increasing. The maximal body mass index (BMI) threshold for kidney transplantation is not clear. The Organ Procurement Transplant Network/Scientific Registry of Transplant Recipients 2019 annual data report showed that the proportion of kidney transplant recipient candidates with a BMI of 30 kg/m² or greater is increasing steadily. Morbid obesity is linked to adverse graft outcomes including delayed graft function, primary nonfunction, and decreased graft survival. Obesity is also an independent risk factor for cardiovascular death in kidney transplant recipients, suggesting that these patients should not be excluded from transplantation based on their BMI because transplantation is associated with lower mortality compared with dialysis. However, many centers exclude obese patients (with different BMI cut-off values) from transplantation to avoid postoperative complications. To minimize the surgical complications of kidney transplantation in obese patients, our center has adopted the robot-assisted kidney transplantation procedure. Our data show that this approach is comparable with historical nonobese controls in the United Network for Organ Sharing database in terms of patient and graft survival. Another surgical option for this group of patients at our center is a combined robotic sleeve gastrectomy and robotic-assisted kidney transplant. In a recent study, this approach showed promising results in terms of weight loss, patient survival, and graft survival, and might become more common in the future.

[Prevalence of chronic kidney disease in France, Esteban study 2014-2016]

BACKGROUND

The epidemiology of chronic kidney disease remains poorly described in France despite its burden. The objective of our study was to provide an estimate of the prevalence of chronic kidney disease stades 3-5 (without replacement therapy) in France.

METHOD

The data come from the Esteban study carried out in France between 2014 and 2016 on a representative sample of the French population. This study included 3,021 adults between 18 and 74 years old. Of these, 2422 adults (80.2%) had serum creatinine assay and were included in this analysis. Renal function was estimated by calculating glomerular filtration rate using the Chronic kidney disease epidemiology collaboration (CKD-Epi) and European Kidney function consortium (EKFC) equations.

RESULTS

The means glomerular filtration rate in our population were respectively 97.5 and 89.0 mL/min/1.73 m² with the CKD-EPI and EKFC equations. The prevalence of chronic renal failure, defined by a glomerular filtration rate less than 60 mL/min/1.73 m² was 1.5% with the CKD-EPI formula and 2.1% with the EKFC formula in adults aged 18 to 74 years. The prevalence was higher in women than in men and increased with age, reaching 6.5% and 9.9% in 65-74 years with the CKD-EPI and EKFC equations, respectively. After extrapolation to the French population, the number of adults with chronic kidney disease stades 3-5 without renal replacement therapy was around 1.6 million.

CONCLUSION

In France, the prevalence of chronic kidney disease stades 3-5 without renal replacement therapy was between 1.5 and 2.1% of the adult population aged 18 to 74.

Associations between obesity, weight change and decreased renal function in Korean type 2 diabetic patients: a longitudinal follow-up study

BACKGROUND

We aimed to examine the associations between the risk of decreased renal function, obesity, and weight changes in Korean type 2 diabetic patients with normal renal function.

METHODS

Type 2 diabetic patients (n = 1060) who visited the diabetic clinic at Soonchunhyang University Bucheon Hospital between 2001 and 2007 with follow up surveys completed in 2016 to 2017 were recruited into the study. Decreased renal function was defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m². Weight change was calculated between baseline and each follow-up survey. Multivariate analysis was used to evaluate the longitudinal association of baseline obesity and weight changes with the risk of decreased renal function.

RESULTS

This study revealed that baseline obesity was associated with the risk of decreased renal function after adjusting for clinical variables in type 2 diabetic patients (odds ratio [OR] 1.40; 95% confidence intervals [CI] 1.08-2.04; p = 0.025). Follow-up (mean = 12 years) revealed that weight gain > 10% was associated with the risk of decreased renal function after adjusting for clinical variables in type 2 diabetic patients with normal renal function at baseline (OR 1.43; CI 1.11-2.00; p = 0.016). Weight loss was not associated with the risk of decreased renal function in type 2 diabetic patients with normal renal function at baseline.

CONCLUSIONS

Baseline obesity was associated with the increased risk of decreased renal function in Korean type 2 diabetic patients with normal renal function. Weight gain > 10% independently predicted the risk of decreased renal function. Large prospective studies are needed to clarify causal associations between obesity, weight change, and decreased renal function in patients with type 2 diabetes.

Impact of body mass index on primary immunoglobulin A nephropathy prognosis: a systematic review and meta-analysis

PURPOSE

The impacts of body mass index (BMI) on the prognosis of primary IgA nephropathy (IgAN) remain controversial. This systematic review and meta-analysis aimed to solve these issues.

METHODS

We searched the PubMed, EMBASE, and Cochrane Library to screen articles investigating the BMI and primary IgAN. BMI was classified according to the World Health Organization as high (≥ 25.0 kg/m²) and low (< 25.0 kg/m²). The baseline renal indexes and the incidences of adverse renal outcomes were focused on.

RESULTS

Six studies with a total of 1723 patients were included in this study. High BMI was demonstrated to be associated with increased baseline levels of serum creatinine (weighted mean difference (WMD) 9.54, 95% confidence interval (CI) 0.63-18.45), blood uric acid (WMD 19.85, 95% CI 10.11-29.59) and urine protein (WMD 0.37, 95% CI 0.21-0.53). Patients with high BMI also showed compromised eGFR at diagnosis (WMD - 8.39, 95% CI - 11.62 to - 5.16) with a higher incidence rate of hypertension (odds ratios (OR) 2.59, 95% CI 1.44-4.66) and higher global optical scores (WMD 1.22, 95% CI 0.70-1.74). Regarding the prognosis, high BMI was significantly associated with the incidence of adverse renal outcomes (OR 2.43, 95% CI 1.66-3.55, P < 0.001) and deteriorated eGFR at the last follow-up (WMD - 11.10, 95% CI - 16.96 to - 5.25, P < 0.001), with non-significantly poorer renal disease-free survival (hazard ratio 1.79, 95% CI 0.58-5.50, P = 0.31).

CONCLUSION

High BMI was associated with severe onset and poor prognosis of primary IgAN. The management of BMI could be a novel method to promote the therapeutic outcomes of primary IgAN.

Modification of the effects of intensive systolic blood pressure control on kidney outcomes by baseline body mass index

AIM

Obesity and intensive systolic blood pressure (SBP) control are independently associated with greater risk of acute kidney injury (AKI) and incident chronic kidney disease (CKD). We examined whether baseline body mass index (BMI) modifies the effects of intensive SBP lowering on AKI or incident CKD.

METHODS

The systolic blood pressure intervention trial (SPRINT) randomized 9361 participants with high blood pressure to an SBP target of either <120 mm Hg or < 140 mm Hg. In a secondary analysis of 9210 SPRINT participants with a baseline BMI of ≥18.5 and < 50 kg/m² , we examined the interactions of baseline BMI and SPRINT SBP intervention on subsequent AKI and incident CKD.

RESULTS

Each 5 kg/m² increase in baseline BMI was associated with higher risk of AKI (hazard ratio [HR] 1.12, 95% confidence interval [CI] 1.01 to 1.25) and incident CKD (HR 1.17, 95% CI 1.01 to 1.32). Intensive SBP control increased the risk of AKI (HR 1.68, 95% CI 1.22-2.11) and incident CKD (HR 3.49, 95% CI 2.47-4.94). The increased risk of AKI with intensive SBP control was consistent across the baseline BMI spectrum (linear interaction p = 0.55); however, the risk of incident CKD with SPRINT intervention increased with higher BMI (linear interaction p = 0.043).

CONCLUSION

The increased risk of adverse kidney events seen with intensive SBP control in the SPRINT persisted across the baseline BMI spectrum. A higher baseline BMI was associated with an augmented risk of incident CKD with intensive SBP control.

Body mass index combined with waist circumference can predict moderate chronic kidney disease: A retrospective study

Overweight and obesity may be associated with poor clinical outcome, including chronic kidney disease (CKD). However, whether body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference (WC) are related to CKD is yet to be elucidated.A total of 7593 adults were divided into 4 groups based on the estimated glomerular filtration rate (eGFR) quartile. The eGFR was calculated with the CKD Epidemiology Collaboration. Multiple linear regression analyzed the association between eGFR and WHR, BMI, and WC. Logistic regression analysis determined whether the CKD patients were associated with WHR, BMI, and WC after adjusting for other variables.The mean age of the cohort was 72.34 ± 7.30 years. Multiple linear regression analysis showed that WC (P = .006) was associated with eGFR, although adjusted by lifestyle factor and biochemical indicators. The individuals in the underweight, overweight, and obese groups had significantly lower eGFR value than those in the healthy weight group in moderate CKD. The eGFR in the overweight group with WHR ≤0.894 was higher than in the healthy weight group with WHR >0.894 group (P = .036). Overweight with WHR ≤0.894 group had a longer WC with a pronounced increase in the hip circumference. Logistic regression analysis showed that the WC (OR = 1.362, P < .001) and BMI (OR = 1.227, P = .031) were independent risk factors for moderate CKD patients. Each standard deviation (SD) of high BMI and WC level was associated with 23.0% and 17.3% higher odds of moderate CKD (OR = 1.230, P = .017 and OR = 1.173, P = .021, respectively).WC is an independent risk factor for eGFR. Combined BMI and WC are important factors that would predict moderate CKD patients.

Obesity related risk for chronic kidney disease progression and cardiovascular disease after propensity score matching

INTRODUCTION

Obesity is a major health problem worldwide. It carries a markedly increased risk for multiple diseases such as type 2 diabetes mellitus, hypertension, cardiovascular disease (CVD) and chronic kidney disease (CKD). To complicate an already difficult topic a new subtype of obesity has been defined lately, the metabolically healthy obese. Our study aimed to clarify the association between obesity, metabolic syndrome and kidney disease progression.

METHODS

Observational retrospective single centre study including 212 patients with stage 3-4 CKD with no previous history of rapid kidney disease progression. Patients were divided according to BMI status and presence of metabolic syndrome. Anthropometric, clinical and laboratory data were collected to follow-up. Propensity score matching was performed for age, albuminuria and baseline renal function. During follow-up renal and cardiovascular events were recorded.

RESULTS

After a mean follow-up of 88.44±36.07 months a total of 18 patients reached the renal outcome in the non-obese group and 21 in the obese group. Differences were not statistically significant (log rank=0.21: p=0.64). Multiple Cox regression analysis showed that obesity was not predictor for worse renal outcomes [HR 1.01, 95% CI 0.45-2.24; p=0.97]. When stratifying the sample according to baseline metabolic syndrome and obesity presence there was no difference in renal survival (log rank=0.852; p=0.35) A total of 48 cardiovascular events were registered: seventeen in the non-obese group and thirty-one in the obese group. Differences in event-free time between both groups were statistically significant (log rank=4.44;p=0.035), especially after four years of follow-up. After stratifying for MS and obesity presence at baseline the event-free time differences where again statistically significant (log rank=16.86;p=0.001), specially for the obese patients with metabolic syndrome.

CONCLUSIONS

Obesity has little impact on chronic kidney disease progression despite the presence or absence of metabolic syndrome in a cohort matched for age, baseline renal function and albuminuria. Obesity conferred greater cardiovascular risk when combined with metabolic syndrome.

Strategies to Treat Obesity in Patients With CKD

Obesity prevalence continues to increase worldwide, accompanied by a rising tide of hypertension, diabetes, and chronic kidney disease (CKD). Although body mass index is typically used to assess obesity in clinical practice, altered body composition (eg, reduced muscle mass and increased visceral adiposity) are common among patients with CKD. Weight loss achieved through behavioral modification or medications reduces albuminuria and in some cases slows the decline in estimated glomerular filtration rate. Use of medications that promote weight loss with favorable cardiovascular risk profiles should be promoted, particularly in patients with type 2 diabetes, obesity, and CKD. For those who fail to achieve weight loss through lifestyle modification, bariatric surgery should be considered because observational studies have shown reductions in risk for estimated glomerular filtration rate decline and kidney failure. Uncertainty persists on the risk to benefit ratio of intentional weight loss in patients with kidney failure due to the lack of prospective trials and limitations of observational data. Regardless, sleeve gastrectomy is increasingly being used for patients with kidney failure and severe obesity, with success in achieving sustained weight loss, improved access to kidney transplantation, and favorable posttransplantation outcomes. More research is needed assessing long-term cardiovascular and kidney outcomes of most weight loss medications.

The Triglyceride-Glucose Index and Obesity-Related Risk of End-Stage Kidney Disease in Austrian Adults

IMPORTANCE

It is unknown whether the triglyceride-glucose (TyG) index as a measure of insulin resistance is associated with the risk of developing end-stage kidney disease (ESKD). Because individuals who are overweight or obese often develop insulin resistance, mediation of the association between body mass index (BMI) and ESKD risk through the TyG index seems plausible but has not been investigated.

OBJECTIVE

To evaluate whether the TyG index is associated with ESKD risk and, if so, to what extent the TyG index mediates the association between BMI and ESKD.

DESIGN, SETTING, AND PARTICIPANTS

A total of 176 420 individuals were recruited during routine health examinations to participate in the Austrian Vorarlberg Health Monitoring and Promotion Program (VHM&PP), a prospective, population-based cohort study with participant enrollment between January 1, 1988, and June 30, 2005, and a mean follow-up of 22.7 years. Data analysis was conducted from March 1, 2020, to September 30, 2020.

EXPOSURES

Body mass index and the logarithmized product of fasting triglyceride and glucose concentrations (TyG index), as determined during the baseline health examination.

MAIN OUTCOMES AND MEASURES

End-stage kidney disease, as indicated by initiation of kidney replacement therapy, either dialysis or kidney transplantation.

RESULTS

Of the 176 420 participants, 94 885 were women (53.8%); mean (SD) age was 42.5 (15.4) years. During a mean (SD) follow-up of 22.7 (6.9) years, 454 (0.3%) participants developed ESKD and 35 234 (20.0%) died. In multivariable-adjusted Cox proportional hazards models, the TyG index was significantly associated with the risk of ESKD, both with (hazard ratio [HR] per 1-SD increase, 1.68; 95% CI, 1.56-1.82) and without (HR per 1-SD increase, 1.79; 95% CI, 1.66-1.93) the inclusion of BMI as a covariate. Mediation analysis using a newly proposed 2-stage regression method for survival data showed that a 5-point increase in BMI increased the risk of ESKD by 58% (HR [total association], 1.58; 95% CI, 1.43-1.75), and that 41.7% of the total association (95% CI, 31.6%-51.8%) was mediated through the TyG index (HR [indirect association], 1.21; 95% CI, 1.18-1.25).

CONCLUSIONS AND RELEVANCE

This study found that the TyG index appeared to be associated with ESKD risk and mediates nearly half of the total association between BMI and ESKD in the general population. Public health efforts aiming at the reduction of body weight might decrease the kidney sequelae of insulin resistance and the burden of ESKD.

Conventional and Genetic Evidence on the Association between Adiposity and CKD

BACKGROUND

The size of any causal contribution of central and general adiposity to CKD risk and the underlying mechanism of mediation are unknown.

METHODS

Data from 281,228 UK Biobank participants were used to estimate the relevance of waist-to-hip ratio and body mass index (BMI) to CKD prevalence. Conventional approaches used logistic regression. Genetic analyses used Mendelian randomization (MR) and data from 394 waist-to-hip ratio and 773 BMI-associated loci. Models assessed the role of known mediators (diabetes mellitus and BP) by adjusting for measured values (conventional analyses) or genetic associations of the selected loci (multivariable MR).

RESULTS

Evidence of CKD was found in 18,034 (6.4%) participants. Each 0.06 higher measured waist-to-hip ratio and each 5-kg/m² increase in BMI were associated with 69% (odds ratio, 1.69; 95% CI, 1.64 to 1.74) and 58% (1.58; 1.55 to 1.62) higher odds of CKD, respectively. In analogous MR analyses, each 0.06-genetically-predicted higher waist-to-hip ratio was associated with a 29% (1.29; 1.20 to 1.38) increased odds of CKD, and each 5-kg/m² genetically-predicted higher BMI was associated with a 49% (1.49; 1.39 to 1.59) increased odds. After adjusting for diabetes and measured BP, chi-squared values for associations for waist-to-hip ratio and BMI fell by 56%. In contrast, mediator adjustment using multivariable MR found 83% and 69% reductions in chi-squared values for genetically-predicted waist-to-hip ratio and BMI models, respectively.

CONCLUSIONS

Genetic analyses suggest that conventional associations between central and general adiposity with CKD are largely causal. However, conventional approaches underestimate mediating roles of diabetes, BP, and their correlates. Genetic approaches suggest these mediators explain most of adiposity-CKD-associated risk.

Incremental Effect of Aging on Obesity-Related Incident Chronic Kidney Disease in the Korean General Population

OBJECTIVES

Obesity may increase the risk of kidney function decline. However, few studies have addressed how age modifies obesity-associated risk of chronic kidney disease (CKD) in the Asian general population.

DESIGN

A community-based prospective cohort study.

SETTING AND PARTICIPANTS

6538 Korean general population with normal kidney function from the Korean Genome and Epidemiology Study Database.

METHODS

Participants were stratified according to age (40-49, 50-59, and 60-69 years old) and body mass index [≥18.5-<23 (normal-weight), ≥23-<27.5 (overweight), and ≥27.5 (obese)]. We conducted Kaplan-Meier and multivariable-adjusted Cox regression analyses to investigate the association of aging and obesity with incident CKD.

RESULTS

During the 12-year follow-up, an overall incidence rate of CKD was 6.1 cases per 1000 person-years. Obese, but not overweight, people had an increased risk of incident CKD compared with normal-weight people in multivariable models adjusted for metabolic factors. When analyzed by 10-year increments, this association was significant only in 60-69-year-old individuals. Kaplan-Meier analysis showed that the incidence of CKD associated with overweight or obesity showed an accentuated increase with age. With reference to normal-weight individuals aged 40-49 years, the adjusted hazard ratio of CKD increased with age regardless of body mass index, and the positive association between obesity and incident CKD was more prominent with increasing age.

CONCLUSIONS AND IMPLICATIONS

Obesity-associated risk of incident CKD was accentuated in older people, and this association was independent of metabolic abnormalities.

Age differences in the relationships between risk factors and loss of kidney function: a general population cohort study

BACKGROUND

Annual decline in kidney function is a widely applied surrogate outcome of renal failure. It is important to understand the relationships between known risk factors and the annual decline in estimated glomerular filtration rate (eGFR) according to baseline age; however, these remain unclear.

METHODS

A community-based retrospective cohort study of adults who underwent annual medical examinations between 1999 and 2013 was conducted. The participants were stratified into different age groups (40-49, 50-59, 60-69, 70-79, and ≥ 80 years) to assess the risk for loss of kidney function. A mixed-effects model was used to estimate the association between risk factors and annual changes in eGFR.

RESULTS

In total, 51,938 participants were included in the analysis. The age group of ≥80 years included 8127 individuals. The mean annual change in eGFR was - 0.39 (95% confidence interval: - 0.41 to - 0.37) mL/min/1.73 m² per year. Older age was related to faster loss of kidney function. In the older age group, higher systolic blood pressure, proteinuria, and current smoking were related to faster loss of kidney function (p trend < 0.01, 0.03, and < 0.01, respectively). Conversely, each age group showed similar annual loss of kidney function related to lower hemoglobin levels and diabetes mellitus (p trend 0.47 and 0.17, respectively).

CONCLUSIONS

Higher systolic blood pressure, proteinuria, and smoking were related to faster loss of kidney function, and a greater effect size was observed in the older participants. More risk assessments for older people are required for personalized care.

Determinants of Virologic Failure among Adult HIV Patients on First-Line Antiretroviral Therapy at Waghimra Zone, Northern Ethiopia: A Case-Control Study

Introduction. The primary goal of antiretroviral therapy (ART) is to reduce the viral load in HIV-infected patients to promote quality of life, as well as to reduce HIV-related morbidity and mortality. A high rate of virologic failure was reported in Waghimra Zone, Northwest Ethiopia, in viral load assessment conducted among HIV-infected patients on ART in the Amhara region. However, there is limited evidence on the determinants of virological failure in the study area. This study aimed to identify the determinants of virological failure among HIV-infected patients on antiretroviral therapy in Waghimra zone, Northern Ethiopia, 2019. Methods. An institutional-based unmatched case-control study was conducted from May 21 to June 30, 2019. Cases were people living with HIV (PLHIV) on ART who had already experienced virological failure; controls were those without virological failure. Data were extracted from 92 cases and 184 controls through chart review using a pretested and structured checklist. The data were entered using Epi Info version 7 and exported to SPSS version 20 for analysis. A multivariate logistic regression analysis was carried out to identify factors associated with virological failure, and variables with a P value <0.05 were considered statistically significant. Results. This study revealed that poor adherence to ART (adjusted odds ratio (AOR) = 4.24, 95% confidence interval (CI): 2.17, 8.31), taking ART for longer than five years (AOR = 3.11, 95% CI: 1.17, 8.25), having drug toxicity (AOR = 3.34, 95% CI: 1.54, 7.23), age of PLHIV ≥ 35 years (AOR = 2.45, 95% CI: 1.29,4.64), and recent CD4 count <200 cells/mm³ (AOR = 3.06, 95% CI: 1.52, 6.13) were factors associated with virologic failure. Conclusion and Recommendation. This study showed that poor adherence to treatment, longer duration on ART, experiencing drug toxicity, older age, and recent CD4 <200 cell/mm³ are factors that increase the risk of virologic failure.

Mortality Risk in Chronic Kidney Disease Patients Transitioning to Dialysis: Impact of Opiate and Non-Opiate Use

BACKGROUND

Population-based studies show there is a high prevalence of chronic kidney disease (CKD) patients suffering from chronic pain. While opiates are frequently prescribed in non-dialysis-dependent CKD (NDD-CKD) patients, there may be toxic accumulation of metabolites, particularly among those progressing to end-stage renal disease (ESRD). We examined the association of opiate versus other analgesic use during the pre-ESRD period with post-ESRD mortality among NDD-CKD patients transitioning to dialysis.

METHODS

We examined a national cohort of US Veterans with NDD-CKD who transitioned to dialysis over 2007-14. Among patients who received ≥1 prescription(s) in the Veterans Affairs (VA) Healthcare System within 1 year of transitioning to dialysis, we examined associations of pre-ESRD analgesic status, defined as opiate, gabapentin/pregabalin, other non-opiate analgesic, versus no analgesic use, with post-ESRD mortality using multivariable Cox models.

RESULTS

Among 57,764 patients who met eligibility criteria, pre-ESRD opiate and gabapentin/pregabalin use were each associated with higher post-ESRD mortality (ref: no analgesic use), whereas non-opiate analgesic use was not associated with higher mortality in expanded case-mix analyses: HRs (95% CIs) 1.07 (1.05-1.10), 1.07 (1.01-1.13), and 1.00 (0.94-1.06), respectively. In secondary analyses, increasing frequency of opiate prescriptions exceeding 1 opiate prescription in the 1-year pre-ESRD period was associated with incrementally higher post-ESRD mortality (ref: no analgesic use).

CONCLUSIONS

In NDD-CKD patients transitioning to dialysis, pre-ESRD opiate and gabapentin/pregabalin use were associated with higher post-ESRD mortality, whereas non-opiate analgesic use was not associated with death. There was a graded association between increasing frequency of pre-ESRD opiate use and incrementally higher mortality.