Obesity Facts and Their Influence on Renal Function Across the Life Span

Obesity and glomerular filtration rate

Obesity has received considerable attention in general medicine and nephrology over the last few years. This condition increases the risk of metabolic syndrome, diabetes mellitus, hypertension, and dyslipidemia, which are the main risk factors for developing chronic kidney disease (CKD). Kidney damage caused by obesity can be explained by many mechanisms, such as sympathetic nervous and renin-angiotensin-aldosterone systems activation, mechanical stress, hormonal unbalance, as well as inflammatory cytokines production. Even though creatinine-based glomerular filtration rate (GFR) equations in obese individuals have been validated (Salazar-Corcoran and CKD-MCQ), changes in body weight after bariatric surgery (BS) leads to changes in creatininemia, affecting its reliability. Thus, an average between creatine and cystatin-based GFR equations would be more appropriate in this setting. Bariatric surgery can reverse diabetes mellitus and improve hypertension, which are the main causes of CKD. Conclusion: GFR can be affected by obesity and BS, and its value should be cautiously evaluated in this setting.

Effect of Obesity on the Pharmacokinetics and Pharmacodynamics of Anticancer Agents

An objective of the Precision Medicine Initiative, launched in 2015 by the US Food and Drug Administration and National Institutes of Health, is to optimize and individualize dosing of drugs, especially anticancer agents, with high pharmacokinetic and pharmacodynamic variability. The American Society of Clinical Oncology recently reported that 40% of obese patients receive insufficient chemotherapy doses and exposures, which may lead to reduced efficacy, and recommended pharmacokinetic studies to guide appropriate dosing in these patients. These issues will only increase in importance as the incidence of obesity in the population increases. This publication reviews the effects of obesity on (1) tumor biology, development of cancer, and antitumor response; (2) pharmacokinetics and pharmacodynamics of small-molecule anticancer drugs; and (3) pharmacokinetics and pharmacodynamics of complex anticancer drugs, such as carrier-mediated agents and biologics. These topics are not only important from a scientific research perspective but also from a drug development and regulator perspective. Thus, it is important to evaluate the effects of obesity on the pharmacokinetics and pharmacodynamics of anticancer agents in all categories of body habitus and especially in patients who are obese and morbidly obese. As the effects of obesity on the pharmacokinetics and pharmacodynamics of anticancer agents may be highly variable across drug types, the optimal dosing metric and algorithm for difference classes of drugs may be widely different. Thus, studies are needed to evaluate current and novel metrics and methods for measuring body habitus as related to optimizing the dose and reducing pharmacokinetic and pharmacodynamic variability of anticancer agents in patients who are obese and morbidly obese.

Rapid increases in BMI waist to height ratio during adolescence and subsequent neurobehavioral deficits

OBJECTIVE

The aim of this study was to explore prospective relationships between changing patterns of BMI/waist to height ratio (WHtR) during adolescence and subsequent neurobehavioral development.

METHODS

In this prospective cohort study, randomized stratified sampling was used to recruit six middle schools and 609 students in Shanghai, China. In Grades 6, 7, and 9, the Youth Self Report scale was used to assess student neurobehavioral status and anthropometric measurements were conducted to calculate BMI z scores and WHtRs. Longitudinal data were analyzed using latent class mixture modeling to delineate trajectories of BMI z scores ("stable," "decreasing," "rapidly increasing") and WHtRs ("stable," "rapidly increasing"), and their associations with neurobehavioral status in Grade 9 were assessed.

RESULTS

In Grades 6 through 9 (ages 11-15 years), the prevalence of overall obesity and abdominal obesity ranged from 10.7% to 13.0% and 13.0% to 19.8%, respectively. Compared with the stable BMI z score trajectory, the rapidly increasing BMI z score trajectory was longitudinally associated with delinquent behavior, aggressive behavior, and externalizing problems (incidence rate ratio: 1.564-1.613, adjusted p < 0.05). Compared with the stable WHtR trajectory, the rapidly increasing WHtR trajectory significantly predicted increased risks of social problems and delinquent behavior (incidence rate ratios: 1.776-1.967, adjusted p < 0.05). Significant associations of the rapidly increasing BMI z score/WHtR trajectories with subsequent neurobehavioral deficits were observed among girls (adjusted p < 0.05) but not among boys (adjusted p > 0.05).

CONCLUSIONS

Rapid increases in BMI or WHtR during adolescence could predict subsequent neurobehavioral deficits, especially for externalizing behaviors. Timely intervention for weight control may be considered to promote adolescent mental health.

Prediction of Early and Long-Term Hospital Readmission in Patients with Severe Obesity: A Retrospective Cohort Study

Adults with obesity have a higher risk of hospitalization and high hospitalization-related healthcare costs. However, a predictive model for the risk of readmission in patients with severe obesity is lacking. We conducted a retrospective cohort study enrolling all patients admitted for severe obesity (BMI ≥ 40 kg/m2) between 2009 and 2018 to the Istituto Auxologico Italiano in Piancavallo. For each patient, all subsequent hospitalizations were identified from the regional database by a deterministic record-linkage procedure. A total of 1136 patients were enrolled and followed up for a median of 5.7 years (IQR: 3.1-8.2). The predictive factors associated with hospital readmission were age (HR = 1.02, 95%CI: 1.01-1.03, p < 0.001), BMI (HR = 1.02, 95%CI: 1.01-1.03, p = 0.001), smoking habit (HR = 1.17, 95%CI: 0.99-1.38, p = 0.060), serum creatinine (HR = 1.22, 95%CI: 1.04-1.44, p = 0.016), diabetes (HR = 1.17, 95%CI: 1.00-1.36, p = 0.045), and number of admissions in the previous two years (HR = 1.15, 95%CI: 1.07-1.23, p < 0.001). BMI lost its predictive role when restricting the analysis to readmissions within 90 days. BMI and diabetes lost their predictive roles when further restricting the analysis to readmissions within 30 days. In conclusion, in this study, we identified predictive variables associated with early and long-term hospital readmission in patients with severe obesity. Whether addressing modifiable risk factors could improve the outcome remains to be established.

Dyslipidemia Is a Risk Factor for Hypothyroidism in Women: A Longitudinal Cohort Study from South Korea

Background: Hypothyroidism is a risk factor for dyslipidemia. We explored whether dyslipidemia is a risk factor for hypothyroidism. Methods: We performed a retrospective analysis of data from a longitudinal cohort study of South Korean adults who underwent medical examination and ≥4 biochemical assessments of thyroid function. The primary outcome was hypothyroidism (thyrotropin [TSH] >4.2 mU/L), and the secondary outcome was severe subclinical hypothyroidism (SCH; TSH ≥10.0 mU/L and normal free thyroxine [fT4] level) or overt hypothyroidism (OH; total triiodothyronine <80 ng/dL and/or fT4 < 0.93 ng/dL and high TSH values). The association of baseline dyslipidemia status with subsequent hypothyroidism was evaluated using Kaplan-Meier curves with the log-rank test and Cox proportional hazards regression models (for the entire population and respective genders). Subgroup analyses according to age (<40 and ≥40 years) and body-mass index (BMI; <23, 23-25, and ≥25 kg/m²) were performed according to gender. Results: We included 1665 participants. During a median follow-up period of 61.0 months, 24.3% (404/1665) individuals developed hypothyroidism. Among these, 36 participants (2.1%) had severe SCH or OH. Excluding patients with a first abnormal TSH level at last follow-up, 44.5% (126/283) of the patients with hypothyroidism had spontaneous TSH normalization. In respective multivariate analyses, dyslipidemia at baseline was independently associated with development of hypothyroidism in women (adjusted hazard ratio [HR] = 2.05 [1.31-3.19], p = 0.002), but not in men (adjusted HR = 1.00 [0.77-1.30], p = 0.991). In women, the presence of dyslipidemia at baseline was associated with development of severe SCH or OH (adjusted HR = 5.33 [1.41-20.12], p = 0.014). In women, respective associations according to age and BMI were as follows: age <40 years, adjusted HR = 2.90 (1.34-6.26, p = 0.007); age ≥40 years, adjusted HR = 1.85 (1.08-3.14, p = 0.023); BMI <23 kg/m², adjusted HR = 1.68 (0.82-3.43, p = 0.151); BMI = 23-25 kg/m², adjusted HR = 2.17 (0.93-5.07, p = 0.071); and BMI ≥25 kg/m², adjusted HR = 2.82 (1.16-6.86, p = 0.022). Conclusions: In Korean adults, dyslipidemia was associated with development of hypothyroidism in women. Our findings require confirmation.

The Effect and Prevalence of Comorbidities in Adolescents With CKD and Obesity

Adolescent obesity and CKD are both significant public health issues independently. When seen as comorbid conditions, they can cause deleterious health outcomes that put them on the fast track to necessitate dialysis or transplantation. This paper analyzes the effects of various biomarkers and comorbidities seen in the intersection of obesity and CKD in the adolescent population. We illustrate the estimated prevalence of these biomarkers and comorbidities through a review of the literature, available treatment, and obesity-related glomerulopathies. We found significant prevalence of the biomarkers, microalbuminuria (9.42% ± 9.31% and interquartile range [IQR] of 9.5%), hypertension (23.60% ± 22.5% and IQR of 9.5%), low high-density lipoprotein (14.34% ± 5.46% and IQR of 5%), hyperfiltration (3.12% ± 5.16% and IQR of 4%), and lower estimated glomerular filtration rate 4.59 ± 2.75 and IQR of 3%. Identification of prevalent biomarkers and their manifestations can serve to inform clinicians what to look for in daily setting and help elucidate the magnitude of this growing issue. Additionally, pertinent treatment options from pharmacotherapy to bariatric surgery are outlined to provide care providers with the full spectrum of treatment options for obesity in adolescent populations.

Amino Acid-Related Metabolic Signature in Obese Children and Adolescents

The growing interest in metabolomics has spread to the search for suitable predictive biomarkers for complications related to the emerging issue of pediatric obesity and its related cardiovascular risk and metabolic alteration. Indeed, several studies have investigated the association between metabolic disorders and amino acids, in particular branched-chain amino acids (BCAAs). We have performed a revision of the literature to assess the role of BCAAs in children and adolescents' metabolism, focusing on the molecular pathways involved. We searched on Pubmed/Medline, including articles published until February 2022. The results have shown that plasmatic levels of BCAAs are impaired already in obese children and adolescents. The relationship between BCAAs, obesity and the related metabolic disorders is explained on one side by the activation of the mTORC1 complex-that may promote insulin resistance-and on the other, by the accumulation of toxic metabolites, which may lead to mitochondrial dysfunction, stress kinase activation and damage of pancreatic cells. These compounds may help in the precocious identification of many complications of pediatric obesity. However, further studies are still needed to better assess if BCAAs may be used to screen these conditions and if any other metabolomic compound may be useful to achieve this goal.

Exploring Renal Changes after Bariatric Surgery in Patients with Severe Obesity

Obesity-related hyperfiltration leads to an increased glomerular filtration rate (GFR) and hyperalbuminuria. These changes are reversible after bariatric surgery (BS). We aimed to explore obesity-related renal changes post-BS and to seek potential mechanisms. Sixty-two individuals with severe obesity were prospectively examined before and 3, 6 and 12 months post-BS. Anthropometric and laboratory data, 24 h-blood pressure, renin-angiotensin-aldosterone system (RAS) components, adipokines and inflammatory markers were determined. Both estimated GFR (eGFR) and albuminuria decreased from the baseline at all follow-up times (p-for-trend <0.001 for both). There was a median (IQR) of 30.5% (26.2–34.4) reduction in body weight. Plasma glucose, glycosylated hemoglobin, fasting insulin and HOMA-index decreased at 3, 6 and 12 months of follow-up (p-for-trend <0.001 for all). The plasma aldosterone concentration (median (IQR)) also decreased at 12 months (from 87.8 ng/dL (56.8; 154) to 65.4 (56.8; 84.6), p = 0.003). Both leptin and hs-CRP decreased (p < 0.001) and adiponectine levels increased at 12 months post-BS (p = 0.017). Linear mixed-models showed that body weight (coef. 0.62, 95% CI: 0.32 to 0.93, p < 0.001) and plasma aldosterone (coef. −0.07, 95% CI: −0.13 to −0.02, p = 0.005) were the independent variables for changes in eGFR. Conversely, glycosylated hemoglobin was the only independent variable for changes in albuminuria (coef. 0.24, 95% CI: 0.06 to 0.42, p = 0.009). In conclusion, body weight and aldosterone are the main factors that mediate eGFR changes in obesity and BS, while albuminuria is associated with glucose homeostasis.