Obesity as an effect modifier of the risk of death in chronic kidney disease

Safety and utility of panniculectomy in renal transplant candidates and end stage renal disease patients

BACKGROUND

As the obesity crisis in the United States continues, some renal transplantation centers have liberalized their BMI criteria necessary for transplant eligibility. More individuals with larger body-habitus related comorbidities with End-Stage Renal Disease (ESRD) now qualify for renal transplantation (RT). Surgical modalities from other fields also interact with this patient population.

METHODS

In order to assess surgical outcomes of panniculectomy in the context of renal transplantation and ESRD, the authors performed a systematic review following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) 2020 guidelines. Due to a paucity of existing primary studies, we retrospectively collected data on patients with ESRD undergoing panniculectomy from the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) to evaluate outcomes of body contouring in this patient population.

RESULTS

From the systematic review, a total of 783 ESRD patients underwent panniculectomy among the studies identified. Of these, 91 patients underwent panniculectomy simultaneously to RT while 692 had their pannus resected prior to kidney transplant. The most common complication was hematoma followed by wound dehiscence. From the NSQIP database, 24 868 patients met the inclusion criteria for analysis. In the setting of renal transplant status, patients with diabetes, hypertension requiring medication, and requiring dialysis were more likely to suffer postoperative complications (OR 1.31, 1.15, and 2.2, respectively). However, upon sub-analysis of specific types of complications, the only retained association was between diabetes and wound complication.

CONCLUSION

Preliminary data show that panniculectomy in ESRD patients appears to be safe, though with a nominal increased risk for complications. Pannus resection does not appear to impact post-transplantation outcomes, including long-term allograft survival. Larger, higher powered, randomized studies are needed to confirm the safety, utility, and medical benefit of panniculectomy in the context of renal transplantation.

Visceral fat and attribute-based medicine in chronic kidney disease

Visceral adipose tissue plays a central role in obesity and metabolic syndrome and is an independent risk factor for both cardiovascular and metabolic disorders. Increased visceral adipose tissue promotes adipokine dysregulation and insulin resistance, leading to several health issues, including systemic inflammation, oxidative stress, and activation of the renin-angiotensin-aldosterone system. Moreover, an increase in adipose tissue directly and indirectly affects the kidneys by increasing renal sodium reabsorption, causing glomerular hyperfiltration and hypertrophy, which leads to increased proteinuria and kidney fibrosis/dysfunction. Although the interest in the adverse effects of obesity on renal diseases has grown exponentially in recent years, the relationship between obesity and renal prognosis remains controversial. This may be attributed to the long clinical course of obesity, numerous obesity-related metabolic complications, and patients' attributes. Multiple individual attributes influencing the pathophysiology of fat accumulation make it difficult to understand obesity. In such cases, it may be effective to elucidate the pathophysiology by conducting research tailored to individual attributes from the perspective of attribute-based medicine/personalized medicine. We consider the appropriate use of clinical indicators necessary, according to attributes such as chronic kidney disease stage, level of visceral adipose tissue accumulation, age, and sex. Selecting treatments and clinical indicators based on individual attributes will allow for advancements in the clinical management of patients with obesity and chronic kidney disease. In the clinical setting of obesity-related nephropathy, it is first necessary to accumulate attribute-based studies resulting from the accurate evaluation of visceral fat accumulation to establish evidence for promoting personalized medicine.

Associations of overweight and obesity with drug-resistant epilepsy

BACKGROUND

Obesity and overweight have been well established as comorbidities of epilepsy in adults. However, the effects of overweight and obesity on the risk of adult drug-resistant epilepsy (DRE) has not been fully assessed. Thus, the objective of this study was to investigate the relationships between categories of body mass index (BMI) and DRE.

METHODS

This was a case-control study. Patients with epilepsy hospitalized for Video electroencephalogram were included in the study from 2015 to 2020. Low/normal weight, overweight, and obesity were defined as BMI<23 and 23-24.9 and ≥25 kg/m², respectively. The proportions of patients diagnosed with DRE in each category were calculated.

RESULTS

A total of 1272 patients with drug-responsive epilepsy and 345 patients with DRE were included in this study. More men than women had DRE (P=0.012). Higher proportions of patients with DRE had a history of status epilepticus (P<0.001), CNS infection (P=0.027), developmental delay (P=0.001), and comorbidity (P<0.001). Obesity (BMI≥25 kg/m²) was associated with an increased risk of DRE (adjusted OR, 2.339; 95% CI, 1.724-3.171). No significant increase in the risk of DRE was found to be associated with overweight. Further stratified analyses by valproic acid (VPA) treatment attenuated the obesity-DRE relationship, but the associations remained statistically significant (adjusted OR, 1.79; 95% CI, 1.15-2.80).

CONCLUSION

Obesity, but not overweight, potentially plays a role in DRE, although confounders, such as antiseizure medications (ASMs) use, need to be explored. In the future, well-designed trials are needed to elucidate this issue.

Management of Obesity in Adults with CKD

Obesity is a leading public health problem that currently affects over 650 million individuals worldwide. Although interest in the adverse effects of obesity has grown exponentially in recent years, less attention has been given to studying its management in individuals with CKD. This relatively unexplored area should be considered a high priority because of the rapid growth and high prevalence of obesity in the CKD population, its broad impact on health and outcomes, and its modifiable nature. This article begins to lay the groundwork in this field by providing a comprehensive overview that critically evaluates the available evidence related to obesity and kidney disease, identifies important gaps in our knowledge base, and integrates recent insights in the pathophysiology of obesity to help provide a way forward in establishing guidelines as a basis for managing obesity in CKD. Finally, the article includes a kidney-centric algorithm for management of obesity that can be used in clinical practice.

Personal Attitudes Toward Weight in Overweight and Obese US Hemodialysis Patients

OBJECTIVE

Overweight and obesity have become increasingly common among end-stage renal disease patients on hemodialysis. Yet, little attention has been given to what hemodialysis patients themselves think of their weight, how they perceive it affects their health, and their attitudes about or desire for weight reduction. We explored these issues using a survey that we designed specifically for the dialysis population.

DESIGN AND METHODS

Sixty-six chronic hemodialysis patients from a US urban center with a body mass index ≥25 kg/m² and stable weight were recruited to participate in a cross-sectional study. The 12-question weight-related survey was validated by retesting a random portion of the study population.

RESULTS

Based on test-retest results, the survey had good to excellent validity. Seventy-nine percent of patients were black, 49% were male, 29% were overweight, and 71% were obese. In general, the patients underestimated their weight excess though 73% were interested in weight loss, of whom nearly half reported attempting to do so mostly through diet and exercise. The majority of participants interested in losing weight felt that doing so would improve their physical and emotional health. The most common barrier to weight reduction was a belief that it was too difficult (55%), followed by a lack of motivation, money, time, resources, and knowledge. Diet was the most common weight loss strategy (85%) considered, whereas bariatric surgery was the least common (6.1%).

CONCLUSIONS

A majority of overweight and obese hemodialysis patients believe their excess weight is adversely impacting their health and quality of life and therefore wish to lose weight.

Obesity and overweight as CAE comorbidities and differential drug response modifiers

OBJECTIVE

This study examined whether overweight and obesity are pretreatment comorbidities and predictors of short-term drug response in newly diagnosed untreated childhood absence epilepsy (CAE). We also examined whether dietary intake accounts for observed pretreatment body mass index (BMI) distribution.

METHODS

Pretreatment height and weight were available for 445 of 446 participants in the NIH-funded CAE comparative effectiveness trial (NCT00088452). Twenty-four-hour dietary recalls were collected. Calculated BMI and dietary intake were standardized for age, sex, and race/ethnicity and compared to age-matched US population from the National Health and Nutrition Examination Survey (NHANES). Logistic regression models tested BMI as a predictor of treatment response. Pharmacokinetic variables were explored as contributors to differential drug response.

RESULTS

After standardizing for demographic differences, children with CAE were more likely to be overweight (19.3% vs 13.8%; p < 0.001) or obese (14.5% vs 11.5%; p < 0.001) than NHANES controls. The combined prevalence of overweight and obesity was 33.8% in the CAE cohort and 25.3% among controls (p < 0.001). Mean daily energy intake (difference -79.5 kcal/day, p = 0.04) and daily carbohydrate intake (difference -10.7 g/day, p = 0.04) were lower in the CAE group than in NHANES controls. With increasing baseline BMI z score, the efficacy and effectiveness of ethosuximide and valproic acid over lamotrigine became more pronounced, despite no significant differences in drug exposure and trough levels.

CONCLUSIONS

Overweight and obesity are more prevalent in children with newly diagnosed CAE than in age-matched peers, despite lower caloric and carbohydrate intake. Baseline BMI may also predict differential drug response, which cannot be attributed to pharmacokinetic differences.

The obese gut microbiome across the epidemiologic transition

The obesity epidemic has emerged over the past few decades and is thought to be a result of both genetic and environmental factors. A newly identified factor, the gut microbiota, which is a bacterial ecosystem residing within the gastrointestinal tract of humans, has now been implicated in the obesity epidemic. Importantly, this bacterial community is impacted by external environmental factors through a variety of undefined mechanisms. We focus this review on how the external environment may impact the gut microbiota by considering, the host’s geographic location ‘human geography’, and behavioral factors (diet and physical activity). Moreover, we explore the relationship between the gut microbiota and obesity with these external factors. And finally, we highlight here how an epidemiologic model can be utilized to elucidate causal relationships between the gut microbiota and external environment independently and collectively, and how this will help further define this important new factor in the obesity epidemic.

The Association Between Body Mass Index and All-Cause Mortality in Patients With Type 2 Diabetes Mellitus: A 5.5-Year Prospective Analysis

Abundances of study in different population have noted that obese cardiovascular disease (CVD) patients have a better prognosis than leaner patients, which refer to the phenomenon of obesity paradox. However, data on the association between body mass index (BMI) and mortality among Asian patients are limited, especially in patients with type 2 diabetes mellitus (T2DM). We investigate the association between BMI and all-cause mortality in Taiwanese patients with T2DM to define the optimal body weight for health.We conducted a longitudinal cohort study of 2161 T2DM patients with a mean follow-up period of 66.7 ± 7.5 months. Using Cox regression models, BMI was related to the risk of all-cause mortality after adjusting all confounding factors.A U-shaped association between BMI and all-cause mortality was observed among all participants. Those with BMIs <22.5 kg/m had a significantly elevated all-cause mortality as compared with those with BMIs 22.5 to 25.0 kg/m, (BMIs 17.5-20.0 kg/m: hazard ratio 1.989, P < 0.001; BMIs 20.0-22.5 kg/m: hazard ratio 1.286, P = 0.02), as did those with BMIs >30.0 kg/m (BMIs 30.0-32.5 kg/m: hazard ratio 1.670, P < 0.001; BMIs 32.5-35.0 kg/m: hazard ratio, 2.632, P < 0.001). This U-shaped association remained when we examined the data by sex, age, smoking, and kidney function.Our study found a U-shaped relationship between all-cause mortality and BMI in Asian patients with T2DM, irrespective of age, sex, smoking, and kidney function. BMI <30 kg/m should be regarded as a potentially important target in the weight management of T2DM.

Leptin signaling molecular actions and drug target in hepatocellular carcinoma

Previous reports indicate that over 13 different tumors, including hepatocellular carcinoma (HCC), are related to obesity. Obesity-associated inflammatory, metabolic, and endocrine mediators, as well as the functioning of the gut microbiota, are suspected to contribute to tumorigenesis. In obese people, proinflammatory cytokines/chemokines including tumor necrosis factor-alpha, interleukin (IL)-1 and IL-6, insulin and insulin-like growth factors, adipokines, plasminogen activator inhibitor-1, adiponectin, and leptin are found to play crucial roles in the initiation and development of cancer. The cytokines induced by leptin in adipose tissue or tumor cells have been intensely studied. Leptin-induced signaling pathways are critical for biological functions such as adiposity, energy balance, endocrine function, immune reaction, and angiogenesis as well as oncogenesis. Leptin is an activator of cell proliferation and anti-apoptosis in several cell types, and an inducer of cancer stem cells; its critical roles in tumorigenesis are based on its oncogenic, mitogenic, proinflammatory, and pro-angiogenic actions. This review provides an update of the pathological effects of leptin signaling with special emphasis on potential molecular mechanisms and therapeutic targeting, which could potentially be used in future clinical settings. In addition, leptin-induced angiogenic ability and molecular mechanisms in HCC are discussed. The stringent binding affinity of leptin and its receptor Ob-R, as well as the highly upregulated expression of both leptin and Ob-R in cancer cells compared to normal cells, makes leptin an ideal drug target for the prevention and treatment of HCC, especially in obese patients.

Obesity in CKD--what should nephrologists know?

Obesity, the epidemic of the 21st century, carries a markedly increased risk for comorbid complications, such as type 2 diabetes, cancer, hypertension, dyslipidemia, cardiovascular disease, and sleep apnea. In addition, obesity increases the risk for CKD and its progression to ESRD. Paradoxically, even morbid obesity associates with better outcomes in studies of ESRD patients on maintenance dialysis. Because the number of obese CKD and maintenance dialysis patients is projected to increase markedly in developed as well as low- and middle-income countries, obesity is a rapidly emerging problem for the international renal community. Targeting the obesity epidemic represents an unprecedented opportunity for health officials to ameliorate the current worldwide increase in CKD prevalence. Nephrologists need more information about assessing and managing obesity in the setting of CKD. Specifically, more precise estimation of regional fat distribution and the amount of muscle mass should be introduced into regular clinical practice to complement more commonly used practical markers, such as body mass index. Studies examining the effects of obesity on kidney disease progression and other clinical outcomes along with weight management strategies are much needed in this orphan area of research.