Obesity as a predictive factor for chronic kidney disease in adults: systematic review and meta-analysis

MASLD and MASH at the crossroads of hepatology trials and cardiorenal metabolic trials

Steatotic liver disease (SLD) is a worldwide public health problem, causing considerable morbidity and mortality. Patients with SLD are at increased risk for major adverse cardiovascular (CV) events, type 2 diabetes mellitus and chronic kidney disease. Conversely, patients with cardiometabolic conditions have a high prevalence of SLD. In addition to epidemiological evidence linking many of these conditions, there is evidence of shared pathophysiological processes. In December 2022, a unique multi-stakeholder, multi-specialty meeting, called MOSAIC (Metabolic multi Organ Science Accelerating Innovation in Clinical Trials) was convened to foster collaboration across metabolic, hepatology, nephrology and CV disorders. One of the goals of the meeting was to consider approaches to drug development that would speed regulatory approval of treatments for multiple disorders by combining liver and cardiorenal endpoints within a single study. Non-invasive tests, including biomarkers and imaging, are needed in hepatic and cardiorenal trials. They can be used as trial endpoints, to enrich trial populations, to diagnose and risk stratify patients and to assess treatment efficacy and safety. Although they are used in proof of concept and phase 2 trials, they are often not acceptable for regulatory approval of therapies. The challenge is defining the optimal combination of biomarkers, imaging and morbidity/mortality outcomes and ensuring that they are included in future trials while minimizing the burden on patients, trialists and trial sponsors. This paper provides an overview of some of the wide array of CV, liver and kidney measurements that were discussed at the MOSAIC meeting.

The risk of herpes zoster is positively associated with obesity, especially morbid obesity

This study aimed to investigate the association between obesity and herpes zoster (HZ) occurrence. This study used data covering 2 million people in Taiwan in 2000, which were obtained from the National Health Insurance Research Database. The cohort study observed aged 20-100 years with obesity from 2000 to 2017 (tracking to 2018). Obesity was indicated by the presence of two or more outpatient diagnoses or at least one admission record. And, obesity was categorized into non-morbid obesity and morbid obesity. Patients with HZ before the index date were excluded. The obesity cohort and control cohort were matched 1:1 according to age, sex, comorbidities, and index year. There were 18,855 patients in both the obesity and control cohorts. The obesity cohort [adjusted hazard ratio (aHR) 1.09] had a higher risk of HZ than the control cohort. Further analysis, the morbid obesity group (aHR 1.47), had a significantly higher risk of HZ than the non-morbid obesity group. Among the patients without any comorbidities, the patients with obesity had a significantly higher risk of developing HZ than the patients without obesity (aHR 1.18). Obese patients are at a higher risk of HZ development, especially in the patients with morbid obesity. Weight reduction is critical for preventing the onset of chronic diseases and decreasing the risk of HZ in patients with obesity.

Prevalence of Chronic Kidney Disease in a High-Risk Population in Urban Lahore, Pakistan: A Cross-sectional Study

Background Chronic kidney disease (CKD) is a globally increasing health concern, and there is a growing focus on early screening and prevention efforts. However, the availability of data on CKD prevalence in Pakistan, particularly in the urban area of Lahore district, is limited. The objective of the Kidney Early Evaluation Program (KEEP) Lahore was to assess the prevalence of CKD in a high-risk population residing in the urban area of Lahore, Pakistan. Methods A cross-sectional study was conducted involving 254 participants, who were over 18 years old and belonged to a high-risk population according to the pre-defined operational definitions. The participants were randomly selected from various towns in Lahore. Screening camps were set up to measure serum creatinine levels and urinary albumin to creatinine ratio (UACR), and then the estimated glomerular filtration rate (eGFR) was calculated using the CKD Epidemiology Collaboration 2021 (CKD EPI) equation. Results Out of the total 254 participants, a diagnosis of CKD was made in 62 (24.2%) individuals. Significant associations were found between CKD and risk factors including hypertension, diabetes, family history of CKD, ischemic heart disease (IHD) or congestive heart failure (CHF), intake of painkillers, and herbal medicines. However, no association was found between obesity (BMI ≥ 30) and CKD. Participants diagnosed with CKD had a mean age of 49.9 years and a mean serum creatinine level of 1.2 mg/dL, while non-CKD participants had a mean age of 43.7 years and a mean serum creatinine level of 0.7 mg/dL. Conclusion Our study revealed that CKD was prevalent in about one-fourth of the participants from the high-risk population of Lahore, indicating a high prevalence of the disease within society. Moreover, hypertension, diabetes, family history of CKD, heart disease, painkillers, and the use of herbal medicines were all significantly linked to CKD in the surveyed sample population.

Effects of Metabolic Syndrome and Its Components on Chronic Kidney Disease and Renal Function: A Two-Sample Mendelian Randomization Study

Objective: The association of metabolic syndrome (MetS) and its components with chronic kidney disease (CKD) and renal function remains controversial in observational studies. To comprehensively investigate the association between MetS and its components with CKD and renal function, a Mendelian randomization (MR) study was performed. Methods: The inverse variance weighting (IVW) of random effects was used as the main estimation method, while MR-Egger and weighted median analysis results were used for auxiliary judgments. Cochran's Q test, MR-Egger intercept test, leave-one-out analysis, and funnel plots were used to assess heterogeneity and pleiotropy. Results: The MR analyses of genetically predicted MetS and its components' association with CKD risk and renal function showed the following causal associations: hypertension with CKD risk; MetS and obesity with increased blood urea nitrogen and decreased estimated glomerular filtration rate based on cystatin C; hypertension and diabetes with increased urine albumin-creatinine ratio and increased risk of microalbuminuria; and CKD with increased triglyceride. Conclusion: Based on genetic data, this study demonstrated an association between hypertension and CKD risk and a causal association between other MetS components and renal function. The early diagnosis and prevention of MetS and its components might be essential for CKD management.

Assessment of the impact of glyphosate and 2,4-D herbicides on the kidney injury and transcriptome changes in obese mice fed a Western diet

The development of chronic kidney disease has been associated with comorbidities resulting from the consumption of Westernized dietary (WD) patterns, including obesity and other metabolic dysfunctions. Kidneys also have a crucial role in the metabolism and excretion of xenobiotics, including herbicides. There is limited knowledge regarding the simultaneous exposure to WD and glyphosate (glypho) and 2,4-D, the most used herbicides globally. Thus, this study examined whether exposure to glypho and/or 2,4-D, either individually or in mixed, could impact the early effects of WD intake on kidney histology and gene expression in a rodent model. Male C57BL6J mice were fed a WD containing 20% lard, 0.2% cholesterol, 20% sucrose, and high sugar solution with 23.1 and 18.9 g/L of D-fructose and D-glucose for six months. During this period, the mice also received glypho (0.05 or 5 mg/kg/day), 2,4-D (0.02 or 2 mg/kg/day), or a mixture of both (0.05 +0.02, 5 +2 mg/kg/day) via intragastric administration five times per week. The doses were within or below the established regulatory limits. While single or mixed exposures did not alter WD-induced obesity, tubular lipid vacuolation, or increased serum creatinine levels; the exposure to higher doses of the mixture (5 +2) reduced the mesangial matrix area and tubular cell proliferation, while increasing the density of F4/80 macrophages in the renal interstitium. In terms of transcriptomic analysis, the herbicide mixture altered the expression of 415 genes in the kidney, which were found to be associated with immune response processes, particularly those related to phagocyte activity. While discrete, findings indicate that herbicide mixtures, rather than single exposures, might induce minor deleterious effects on the kidneys of obese mice under WD intake.

Nonalcoholic Fatty Liver Disease and Chronic Kidney Disease Cross Talk

Nonalcoholic fatty liver disease is a multisystem condition with effects beyond the liver. The identification of chronic kidney disease as an independent mediator of nonalcoholic fatty liver disease or associated entity with shared cardiometabolic risk factors remains controversial and continues to draw scientific interest. With increasing prevalence of nonalcoholic fatty liver disease and lack of Food and Drug Administration approved therapies, these shared cardiometabolic risk factors have drawn significant attention. In this article, we review shared pathophysiological mechanisms between nonalcoholic fatty liver disease and chronic kidney disease along with current treatment strategies that might be useful for both disease processes.

The Effect of Metabolic Syndrome and Its Individual Components on Renal Function: A Meta-Analysis

BACKGROUND

Observational studies have reported inconsistent findings in the relationship between metabolic syndrome (MetS), its components, and loss of renal function, mainly including eGFR decline, new-onset CKD, and ESRD. This meta-analysis was performed to investigate their potential associations.

METHODS

PubMed and EMBASE were systematically searched from their inception to 21 July 2022. Observational cohort studies in English assessing the risk of renal dysfunction in individuals with MetS were identified. Risk estimates and their 95% confidence intervals (CIs) were extracted and pooled using the random-effects approach.

RESULTS

A total of 32 studies with 413,621 participants were included in the meta-analysis. MetS contributed to higher risks of renal dysfunction (RR = 1.50, 95% CI = 1.39-1.61) and, specifically, rapid decline in eGFR (RR 1.31, 95% CI 1.13-1.51), new-onset CKD (RR 1.47, 95% CI 1.37-1.58), as well as ESRD (RR 1.55, 95% CI 1.08-2.22). Moreover, all individual components of MetS were significantly associated with renal dysfunction, while elevated BP conveyed the highest risk (RR = 1.37, 95% CI = 1.29-1.46), impaired fasting glucose with the lowest and diabetic-dependent risk (RR = 1.20, 95% CI = 1.09-1.33).

CONCLUSIONS

Individuals with MetS and its components are at higher risk of renal dysfunction.

Irisin protects against obesity-related chronic kidney disease by regulating perirenal adipose tissue function in obese mice

Background

Compared with typical visceral fat deposits in obesity and metabolic syndrome, perirenal adipose tissue (PRAT) dysfunction is more closely linked to obesity-related chronic kidney disease (OB-CKD). The myokine irisin reportedly promotes positive outcomes in metabolic disease. This study investigated whether irisin could reduce urinary albumin excretion and demonstrate renoprotective effects through the regulation of PRAT function in obese mice.

Methods

C57BL/6 J mice received a high-fat diet (HFD) with or without concurrent administration of irisin. Glucose tolerance, plasma levels of free fatty acids, and urinary albumin excretion were assessed, along with renal morphology. The vascular endothelial growth factor and nitric oxide in glomeruli were also analyzed, in addition to PRAT function-associated proteins.

Results

Irisin administration significantly reduced the final body weight, fat mass, and free fatty acids, without reducing PRAT mass, in HFD mice. Furthermore, irisin decreased urinary albumin excretion and attenuated both renal fibrosis and lipid accumulation. Irisin administration led to increases in PRAT function-associated proteins, including sirtuin1, uncoupling protein-1, and heme-oxygenase-1. Ex vivo treatment of PRAT and glomeruli with irisin also restored PRAT function. Finally, irisin treatment restored the vascular endothelial growth factor–nitric oxide axis.

Conclusions

Irisin attenuated metabolic disorders and protected against OB-CKD by normalizing the PRAT–kidney axis. These results suggest that agents targeting PRAT activation might be useful for treatment of OB-CKD.

Pharmacological Management of Obesity: A Century of Expert Opinions in Cecil Textbook of Medicine

BACKGROUND

Innovations in drug therapy for obesity have had a limited impact on the body mass index, prevalence of medical complications, quality of life, and work potential of a substantial majority of affected persons.

STUDY QUESTION

What are the milestones of the changes in the expert approach to the pharmacological management of obesity in the past century?

STUDY DESIGN

To determine the changes in the experts' approach to the management of obesity, as presented in a widely used textbook in the United States.

DATA SOURCES

The primary sources were chapters describing the management of obesity in the 26 editions of Cecil Textbook of Medicine published from 1927 through 2020. Secondary sources were publications retrieved from Medline that clarified technical issues related to the development, regulatory approval, and use of the drugs mentioned in the Cecil Textbook of Medicine.

RESULTS

Pharmacological interventions aimed at increasing caloric expenditures through thermogenesis were recommended from 1927 through 1943. Thyroid extracts were prescribed even in the absence of demonstrated hypothyroidism or decreased basal metabolic rate throughout this period. Dinitrophenol was mentioned in 1937, but was banned soon thereafter. Appetite suppression with amphetamine was considered useful from 1943 through 1988, after which the drug was replaced with other centrally acting molecules, such as fenfluramine in 1988, sibutramine in 2000, and rimonabant in 2008, which were in turn withdrawn because of major adverse effects. In the past decade, obesity has been treated with the appetite suppressants phentermine-topiramate, bupropion-naltrexone, lorcaserin, and liraglutide, and with orlistat, a drug promoting fat malabsorption. The change in weight produced by these drugs is generally modest and transient.

CONCLUSIONS

The pharmacological management of obesity has remained frustratingly inefficient. The reasons for the relative lack of success may reside in the ever-growing access to dense, palatable, and relatively inexpensive food, coupled with the decrease in energy expenditure created by a sedentary lifestyle.

Trends in obesity across Canada from 2005 to 2018: a consecutive cross-sectional population-based study

BACKGROUND

Obesity is increasingly prevalent worldwide and is becoming an epidemic in many countries, including Canada. We sought to describe and analyze temporal obesity trends in the Canadian adult population from 2005 through 2018 at the national and provincial or territorial levels.

METHODS

We conducted a consecutive, cross-sectional study using data from 7 sequential Canadian Community Health Survey (CCHS) cycles (2005 to 2017/18). We included data from Canadian adults (age ≥ 18 yr) who participated in at least 1 of the 7 consecutive CCHS cycles and who had body mass index values (calculated by Statistics Canada based on respondents' self-reported weight and height). Obesity prevalence (adjusted body mass index ≥ 30) was a primary outcome variable. We analyzed temporal trends in obesity prevalence using Pearson χ² tests with Bonferroni adjustment, and the Cochran-Armitage test of trend.

RESULTS

We included data from 746 408 (403 582 female and 342 826 male) CCHS participants. Across Canada, the prevalence of obesity increased significantly between 2005 and 2017/18, from 22.2% to 27.2% (p < 0.001). We observed increases across both sexes, all age groups and all Canadian provinces and territories (p < 0.001). In 2017/18, the prevalence of obesity was higher among males than females (28.9% v. 25.4%; p < 0.001); the prevalence among adults aged 40-69 years exceeded 30%. In 2017/18, Newfoundland and Labrador had the highest prevalence (39.4%), and British Columbia had the lowest (22.8%) prevalence of obesity. Over the 14-year study period, Quebec and Alberta exhibited the largest relative increases in obesity.

INTERPRETATION

In 2017/18, more than 1 in 4 adult Canadians lived with obesity, and from 2005 to 2017/18, the prevalence of obesity among adults in Canada increased substantially across sexes, age groups and all Canadian provinces and territories to 27.2%. Our findings call for urgent actions to identify, implement and evaluate solutions for obesity prevention and management in all Canadian provinces and territories.

Role of gut-kidney axis in renal diseases and IgA nephropathy

PURPOSE OF REVIEW

Growing evidence show the importance of gut/kidney axis in renal diseases. Advances in gut microbiome sequencing, associated metabolites, detection of gut permeability and inflammation provide new therapeutic strategies targeting gut for kidney diseases and particularly for Immunoglobulin A (IgA) nephropathy (IgAN).

RECENT FINDINGS

The diversity and composition of gut flora have been recently deeply explored in kidney diseases. Modulation and depletion of microbiota in animal models allowed the understanding of molecular mechanisms involved in the crosstalk between gut, immune system and kidney. New clinical trials in order to positively modulate microbiota result in improvement of gastrointestinal disorders and inflammation in patients suffering with kidney diseases.

SUMMARY

The investigation of gut alterations in kidney diseases open new therapeutic strategies. In IgAN, targeted treatments for intestinal inflammation and modifications of gut microbiota seem promising.