Cohort Study and Bias Analysis of the Obesity Paradox Across Stages of Chronic Kidney Disease

Stigma, Bias, and the Shortfalls of Body Mass Index: A Reflection on the State of Weight Management

Obesity is a complex, multifactorial chronic disease. With the development of novel endoscopic techniques and devices for the treatment of obesity, combined with expanding indications for medications, gastroenterologists are more involved in weight management than ever before. Despite the modern definition of obesity as a disease, weight bias and stigma are pervasive in the medical community and beyond. These sentiments contribute to worse outcomes for patients. Furthermore, body mass index (BMI), which is the primary metric to define obesity, does not always approximate visceral adiposity in all populations. A weight-centric model of health, which relies on BMI, misclassifies individuals who may be metabolically healthy at elevated weights. This review will summarize the history of BMI, highlight the problems that arise with a weight-centric model of health, and propose alternative weight-inclusive frameworks for assessment and intervention.

Case Study: The Weighty Issue of Treatment Options for Obese Dialysis Patients

Obesity is a complex chronic disease and common comorbidity in kidney failure and is the leading causes of death and disability in this population. Guidelines do not specifically address the preferred weight management option(s) for obesity while on dialysis. Large body size is a limiting factor for consideration of a kidney transplantation. We report on a successful bariatric surgery with a young adult after 5.5 years on dialysis with hope for a future transplant. Success was demonstrated with progressive weight loss without adverse changes in renal clinical markers accompanied by improvements in exercise tolerance and health status thereby improving her suitability for a kidney transplant. Further studies and guidelines are needed to address weight loss options for those with obesity on dialysis and want to lose weight.

The age-related obesity paradigm: results from two large prospective cohort studies

BACKGROUND

The obesity paradigm has been a health concern globally for many years, its meaning is controversial. In this study, we assess the characteristics and causes of obesity paradigm and detail the mediation of obesity and inflammation on survival.

METHODS

The original cohort included participants from the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018, a prospective cohort of a nationally representative sample of adult participants; the oncology validation cohort included patients from the Investigation on Nutrition Status and Clinical Outcome of Common Cancers (INSCOC) from 2013 to 2021, a prospective cohort of Chinese patients with cancer. Survival analysis was performed using weighted (NHANES) or unweighted (INSCOC) Cox survival analyses. The normal BMI group was used as a reference for all comparisons. Systemic inflammation was defined as neutrophil-to-lymphocyte ratio (NLR) > 3. Model-based causal mediation analysis was used to identify the mediators.

RESULTS

A total of 52 270 (weighted population: 528506229) participants of the NHANES [mean follow-up times: 10.2 years; mean age (SD): 47 (19.16) years] were included in the original cohort; and a total of 17 418 patients with cancer of INSCOC [mean follow-up times: 2.9 years; mean age (SD): 57.37 (11.66) years] were included in the validation cohort. In the subgroups of all the participants, the obesity paradigm was more apparent in older participants and participants with disease [HR (95% CI): age ≥ 65 years, 0.84 (0.76, 0.93); with cancer, 0.84 (0.71, 0.99); with CVD, 0.74 (0.65, 0.85)]. As aged, the protective effect of a high BMI on survival gradually increased and a high BMI showed the effect of a protective factor on older participants [for obese II, HR (95% CI): young adults, 1.91 (1.40, 2.62); middle age, 1.56 (1.28, 1.91); old adults, 0.85 (0.76, 0.96]). The aged-related obesity paradigm in patients with cancer from the NHANES was verified in the INSCOC cohorts [for obese, HR (95%CI): 0.65 (0.52, 0.81)]. The NLR is an important mediator of the effect of BMI on survival (proportion of mediation = 15.4%).

CONCLUSIONS

The obesity paradigm has a strong correlation with age. Relative to normal weight, obese in young people was association with higher all-cause mortality, and obese in elderly people was not association with higher mortality. The protection of obesity is association with systemic inflammation.

Lipid parameters, adipose tissue distribution and prognosis prediction in chronic kidney Disease patients

BACKGROUND

Lipid management in clinic is critical to the prevention and treatment of Chronic kidney disease (CKD), while the manifestations of lipid indicators vary in types and have flexible association with CKD prognosis.

PURPOSE

Explore the associations between the widely used indicators of lipid metabolism and their distribution in clinic and CKD prognosis; provide a reference for lipid management and inform treatment decisions for patients with non-dialysis CKD stage 3-5.

METHODS

This is a retrospective cohort study utilizing the Self-Management Program for Patients with Chronic Kidney Disease Cohort (SMP-CKD) database of 794 individuals with CKD stages 3-5. It covers demographic data, clinical diagnosis and medical history collection, laboratory results, circulating lipid profiles and lipid distribution assessments. Primary endpoint was defined as a composite outcome(the initiation of chronic dialysis or renal transplantation, sustained decline of 40% or more in estimated glomerular filtration rate (eGFR), doubled of serum creatinine (SCr) from the baseline, eGFR less than 5 mL/min/1.73m2, or all-cause mortality). Exposure variables were circulating lipid profiles and lipid distribution measurements. Association were assessed using Relative risks (RRs) (95% confidence intervals (CIs)) computed by multivariate Poisson models combined with least absolute shrinkage and selection operator (LASSO) regression according to categories of lipid manifestations. The best model was selected via akaike information criterion (AIC), area under curve (AUC), receiver operating characteristic curve (ROC) and net reclassification index (NRI). Subgroup analysis and sensitivity analysis were performed to assess the interaction effects and robustness..

RESULTS

255 individuals reached the composite outcome. Median follow-up duration was 2.03 [1.06, 3.19] years. Median age was 58.8 [48.7, 67.2] years with a median eGFR of 33.7 [17.6, 47.8] ml/min/1.73 m2. Five dataset were built after multiple imputation and five category-based Possion models were constructed for each dataset. Model 5 across five datasets had the best fitness with smallest AIC and largest AUC. The pooled results of Model 5 showed that total cholesterol (TC) (RR (95%CI) (per mmol/L) :1.143[1.023,1.278], P = 0.018) and percentage of body fat (PBF) (RR (95%CI) (per percentage):0.976[0.961,0.992], P = 0.003) were significant factors of composite outcome. The results indicated that comprehensive consideration of lipid metabolism and fat distribution is more critical in the prediction of CKD prognosis..

CONCLUSION

Comprehensive consideration of lipid manifestations is optimal in predicting the prognosis of individuals with non-dialysis CKD stages 3-5.

Anthropometric Measures of Adiposity as Markers of Kidney Dysfunction: A Cross-Sectional Study

The present study was designed to provide information on the ability of several different anthropometric markers to reflect the renal impairment associated with body weight increase and to predict the development of renal alterations linked to overweight and obesity. In 574 subjects representative of the general population of the Pressioni Arteriose Monitorate e Loro Associazioni (PAMELA) study, with an age range between 57 and 73 years, we investigated the association between different anthropometric markers of body fat, as alternative to body mass index, and renal failure, to obtain information useful for determining their potential predictive value. Renal dysfunction was significantly associated with almost all anthropometric markers of adiposity related to body weight and body shape. After adjustment for confounders, such as age, sex, office blood pressure, serum glucose, antihypertensive drugs and smoking habit, association remained significant only for waist-to-hip ratio (WHR), lipid accumulation product (LAP) and visceral adiposity index (VAI). These 3 markers also displayed at the receiver operating curves (ROC) analysis the best ability to detect subjects with or without kidney dysfunction. The results of the present study provide evidence that WHR, LAP and VAI represent the best markers of renal dysfunction associated with visceral body fat accumulation.

Metabolically healthy obesity is associated with higher risk of both hyperfiltration and mildly reduced estimated glomerular filtration rate: the role of serum uric acid in a cross-sectional study

BACKGROUND

The impact of metabolically healthy obesity (MHO) on kidney dysfunction remains debatable. Moreover, few studies have focused on the early stages of kidney dysfunction indicated by hyperfiltration and mildly reduced eGFR. Thus, we aimed to investigate the association between the MHO and early kidney dysfunction, which is represented by hyperfiltration and mildly reduced estimated glomerular filtration rate (eGFR), and to further explore whether serum uric acid affects this association.

METHODS

This cross-sectional study enrolled 1188 residents aged ≥ 40 years old from Yonghong Communities. Metabolically healthy phenotypes were categorized based on Adult Treatment Panel III criteria. Obesity was defined as body mass index (BMI) ≥ 25 kg/m². Mildly reduced eGFR was defined as being in the range 60 < eGFR ≤ 90 ml/min/1.73m². Hyperfiltration was defined as eGFR > 95th percentile after adjusting for sex, age, weight, and height.

RESULTS

Overall, MHO accounted for 12.8% of total participants and 24.6% of obese participants. Compared to metabolically healthy non-obesity (MHNO), MHO was significantly associated with an increased risk of mildly reduced eGFR (odds ratio [OR] = 1.85, 95% confidence interval [CI]  1.13-3.01) and hyperfiltration (OR = 2.28, 95% CI 1.03-5.09). However, upon further adjusting for uric acid, the association between the MHO phenotype and mildly reduced eGFR was reduced to null. Compared with MHNO/non-hyperuricemia, MHO/non-hyperuricemia was associated with an increased risk of mildly reduced eGFR (OR = 2.04, 95% CI  1.17-3.58), whereas MHO/hyperuricemia was associated with an observably increased risk (OR = 3.07, 95% CI  1.34-7.01).

CONCLUSIONS

MHO was associated with an increased risk of early kidney dysfunction, and the serum uric acid partially mediated this association. Further prospective studies are warranted to clarify the causality.

Metabolic and histomorphological changes of adipose tissue in cachexia

PURPOSE OF REVIEW

To describe the role of the main changes occurring in adipose tissue during cachexia and how these affects patient's outcomes, with a specific focus on cancer.

RECENT FINDINGS

In cachexia, the changes within the adipose tissue have been recently described as the presence of inflammatory infiltration (T-lymphocytes and macrophages), enhanced fibrosis, and the occurrence of beige adipocytes (i.e., browning). The latter one is a process driving cachexia enhancing thermogenesis, primarily via modulation of uncoupling protein 1. Also, increased lipolysis of white adipose tissue, especially in cancer, via higher expression of hormone sensible and adipose tissue triglyceride lipases, was detected in experimental models and in human adipose tissue. Other systemic metabolic alterations occur in association with changes in adiposity, including insulin resistance and increased inflammation, all conditions associated with a worse outcome. Moreover, these profound metabolic alterations were shown to be implicated in several consequences, including extreme and progressive unvoluntary body weight loss.

SUMMARY

Alterations in adiposity occur early during cachexia. Adipose tissue atrophy, as well as metabolic changes of white adipose tissues were observed to be pivotal in cachexia, and to be implicated in several clinical complications and poor prognosis.Further research is necessary to clarify the mechanisms underlying the loss of adiposity and therefore to identify novel therapeutic options to counteract this phenomenon in cachexia.