Obesity and kidney disease: hidden consequences of the epidemic

Obesity, Hyperfiltration, and Early Kidney Damage: A New Formula for the Estimation of Creatinine Clearance

CONTEXT

Glomerular hyperfiltration may represent a direct pathogenetic link between obesity and kidney disease. The most widely used methods to estimate creatine clearance such as Cockroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) have not been validated in subjects with obesity.

OBJECTIVE

The performance of prediction formulas was compared with measured creatinine clearance (mCrCl) in subjects with obesity.

METHODS

The study population included 342 patients with obesity (mean BMI 47.6 kg/m2) without primary kidney disease. A urine collection was performed over 24 hours for measurement of CrCl.

RESULTS

mCrCl increased with body weight. The CG formula showed an overestimation at high CrCl, whereas an underestimation resulted from CKD-EPI and MDRD. To improve the accuracy of estimated CrCl (eCrCl), a new CG-based formula was developed:53+0.7×(140-Age)×Weight/(96xSCr)×(0.85iffemale)A cut-off point for BMI of 32 kg/m2 was identified, at which the new formula may be applied to improve eCrCl.

CONCLUSION

In patients with obesity the glomerular filtration rate increases with body weight, and it is associated with the presence of albuminuria, suggesting an early kidney injury. We propose a novel formula that improves the accuracy of eCrCl to avoid missed diagnoses of hyperfiltration in patients with obesity.

Role of miR-379 in high-fat diet-induced kidney injury and dysfunction

Obesity is associated with increased risk for diabetes and damage to the kidneys. Evidence suggests that miR-379 plays a role in the pathogenesis of diabetic kidney disease. However, its involvement in obesity-induced kidney injury is not known and was therefore investigated in this study by comparing renal phenotypes of high-fat diet (HFD)-fed wild-type (WT) and miR-379 knockout (KO) mice. Male and female WT mice on the HFD for 10 or 24 wk developed obesity, hyperinsulinemia, and kidney dysfunction manifested by albuminuria and glomerular injuries. However, these adverse alterations in HFD-fed WT mice were significantly ameliorated in HFD-fed miR-379 KO mice. HFD feeding increased glomerular expression of miR-379 and decreased its target gene, endoplasmic reticulum (ER) degradation enhancing α-mannosidase-like protein 3 (Edem3), a negative regulator of ER stress. Relative to the standard chow diet-fed controls, expression of profibrotic transforming growth factor-β1 (Tgf-β1) was significantly increased, whereas Zeb2, which encodes ZEB2, a negative regulator of Tgf-β1, was decreased in the glomeruli in HFD-fed WT mice. Notably, these changes as well as HFD-induced increased expression of other profibrotic genes, glomerular hypertrophy, and interstitial fibrosis in HFD-fed WT mice were attenuated in HFD-fed miR-379 KO mice. In cultured primary glomerular mouse mesangial cells (MMCs) isolated from WT mice, treatment with high insulin (mimicking hyperinsulinemia) increased miR-379 expression and decreased its target, Edem3. Moreover, insulin also upregulated Tgf-β1 and downregulated Zeb2 in WT MMCs, but these changes were significantly attenuated in MMCs from miR-379 KO mice. Together, these experiments revealed that miR-379 deletion protects mice from HFD- and hyperinsulinemia-induced kidney injury at least in part through reduced ER stress.NEW & NOTEWORTHY miR-379 knockout mice are protected from high-fat diet (HFD)-induced kidney damage through key miR-379 targets associated with ER stress (Edem3). Mechanistically, treatment of mesangial cells with insulin (mimicking hyperinsulinemia) increased expression of miR-379, Tgf-β1, miR-200, and Chop and decreases Edem3. Furthermore, TGF-β1-induced fibrotic genes are attenuated by a GapmeR targeting miR-379. The results implicate a miR-379/EDEM3/ER stress/miR-200c/Zeb2 signaling pathway in HFD/obesity/insulin resistance-induced renal dysfunction. Targeting miR-379 with GapmeRs can aid in the treatment of obesity-induced kidney disease.

Obesity-Related Chronic Kidney Disease: Principal Mechanisms and New Approaches in Nutritional Management

Obesity is the epidemic of our era and its incidence is supposed to increase by more than 30% by 2030. It is commonly defined as a chronic and metabolic disease with an excessive accumulation of body fat in relation to fat-free mass, both in terms of quantity and distribution at specific points on the body. The effects of obesity have an important impact on different clinical areas, particularly endocrinology, cardiology, and nephrology. Indeed, increased rates of obesity have been associated with increased risk of cardiovascular disease (CVD), cancer, type 2 diabetes (T2D), dyslipidemia, hypertension, renal diseases, and neurocognitive impairment. Obesity-related chronic kidney disease (CKD) has been ascribed to intrarenal fat accumulation along the proximal tubule, glomeruli, renal sinus, and around the kidney capsule, and to hemodynamic changes with hyperfiltration, albuminuria, and impaired glomerular filtration rate. In addition, hypertension, dyslipidemia, and diabetes, which arise as a consequence of overweight, contribute to amplifying renal dysfunction in both the native and transplanted kidney. Overall, several mechanisms are closely related to the onset and progression of CKD in the general population, including changes in renal hemodynamics, neurohumoral pathways, renal adiposity, local and systemic inflammation, dysbiosis of microbiota, insulin resistance, and fibrotic process. Unfortunately, there are no clinical practice guidelines for the management of patients with obesity-related CKD. Therefore, dietary management is based on the clinical practice guidelines for the nutritional care of adults with CKD, developed and published by the National Kidney Foundation, Kidney Disease Outcome Quality Initiative and common recommendations for the healthy population. Optimal nutritional management of these patients should follow the guidelines of the Mediterranean diet, which is known to be associated with a lower incidence of CVD and beneficial effects on chronic diseases such as diabetes, obesity, and cognitive health. Mediterranean-style diets are often unsuccessful in promoting efficient weight loss, especially in patients with altered glucose metabolism. For this purpose, this review also discusses the use of non-classical weight loss approaches in CKD, including intermittent fasting and ketogenic diet to contrast the onset and progression of obesity-related CKD.

Phenotypic Characterization of Chronic Kidney Patients Through Hierarchical Clustering

Chronic kidney disease is a major public health problem around the world and this disease early diagnosis is still a great challenge as it is asymptomatic in its early stages. Thus, in order to identify variables capable of assisting CKD diagnosis and monitoring, machine learning techniques and statistical analysis use has shown itself to be extremely promising. For this work, unsupervised machine learning, statistical analysis techniques and discriminant analysis were used.Clinical Relevance - Discriminating variables characterization assist to differentiate groups of patients in different stages of Chronic Kidney Disease and it has important outcomes in the development of future models to aid clinical decision-making, as they can generate models with a greater predictive capacity for Chronic Kidney Disease, predominantly aiding the early diagnosis capacity of this pathology.

Comparative risk of fracture for bariatric procedures in patients with obesity: A systematic review and Bayesian network meta-analysis

OBJECTIVE

Bariatric surgery (malabsorptive [i.e., biliopancreatic diversion, BPD], restrictive [i.e., sleeve gastrectomy, SG; adjustable gastric banding, AGB] and mixed [i.e., gastric bypass, GB] procedures) has been reported to be associated with an increased risk of fracture; however, which procedure poses the greatest risk of fracture is still controversial. The aim of the current meta-analysis was to investigate the degree of fracture risk after different bariatric procedures.

MATERIAL AND METHODS

Electronic databases, including Medline/PubMed, EMBASE and Cochrane library, were systematically searched from inception to July 11, 2019 with no language restrictions to retrieve randomized controlled trials (RCTs) or cohort studies evaluating the impact of any kind of bariatric surgery on postoperative fractures in patients with obesity. Pairwise meta-analysis and Bayesian network meta-analysis were performed to pool the outcome estimates of interest, including fracture incidence and fracture risk. The values of the surface under the cumulative ranking (SUCRA) probability for fracture risk were calculated and sorted according to the different surgical procedures.

RESULTS

A total of twelve studies published between 2010 and 2019, comprising 159,916 participants with obesity were identified for the analysis. The incidence of fracture increased from 3% (95% confidence interval [CI] 2-4%) in patients with non-surgical intervention (drug treatment, alteration in life style and diet control) to 5% (95% CI 4-7%) in those who had undergone bariatric surgery (pooled relative risk [RR] = 1.41 95% CI: 1.22-1.63). Network meta-analysis revealed that based on the SUCRA ranking of the different surgical procedures, the malabsorptive procedure had the highest possibility of increased fracture risk in patients with obesity (74.75%), followed by the mixed procedures (73.85%), nonsurgical intervention (43.55%) and the restrictive procedure (7.85%); for different surgery types. The BPD group had the highest possibility of increased fracture risk (99.49%), followed by the GB (74.92%), nonsurgical intervention (44.49%), AGB (26.64%) and SG (4.45%) groups.

CONCLUSIONS

Significant differences exist among different bariatric surgeries impacting on fracture risk. The malabsorptive and mixed procedures, but not the restrictive procedure, increase the postoperative risk of fracture. Considering the weight-reduction effects and fracture risk, the sleeve gastrectomy procedure may be the best choice for patients with obesity, especially those who are susceptible to osteoporosis.

Plasma triglyceride levels and central obesity predict the development of kidney injury in Chinese community older adults

Objective: Despite the achievement of blood glucose, blood pressure targets, the risk for kidney injury remains high among older adults. This observational retrospective study investigated whether high TG or high WC contribute to this high residual risk for kidney injury. Methods: A total of 843 elderly from Dongli Community, Tianjin, China, we selected 666 individuals with a baseline estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 and negative microalbuminuria completing a 3-year follow-up. At baseline, subjects were grouped according to the levels of TG and WC. The primary outcome was the incidence of kidney injury, defined as low eGFR (eGFR <60 mL/min/1.73 m2) or reduced eGFR (eGFR reduced >25%) or UACR ≥30 mg/g. Results: Overall, 6.01% developed low eGFR, 11.11% reduced eGFR, 25.98% UACR ≥30 mg/g, and 3.45% low eGFR and UACR ≥30mg/g after 3-year follow-up. TG ≥1.7 mmol/L increased the risk of eGFR <60 mL/min/1.73 m2 by 1.44-fold, of UACR ≥30 mg/g by 32%, and of developing both abnormality by 1.41-fold in model 1; further adjustment for potential confounders factors, the association is slightly weakened in model 2 and 3; WC (≥90 cm in men and ≥85 cm in women) were associated with a 1.68-fold higher risk of eGFR <60 mL/min/1.73 m2 and a 1.43-fold risk of UACR ≥30 mg/g and a 1.89-fold risk of developing both abnormality in model 1. Further adjustment for potential confounders factors, the association is slightly weakened in model 2 and 3. Conclusions: In a population of Chinese community-dwelling older adults, high TG and central obesity were risk factors for the development of kidney injury over 3 years.

Prevalence of positive chronic kidney Disease screening in professional male long haul drivers at risk of cardiovascular Disease in Lagos, Nigeria: a cross-section study

BACKGROUND

Professional drivers are known to be at high risk for cardiovascular disease (CVD) on account of the higher prevalence co-occurring risk factors they harbour. Chronic kidney disease (CKD) and CVD share similar risk factors. Both impact each other adversely. The renal profile of professional drivers in Nigeria is not well characterised. We decided to study the prevalence of positive CKD screening amongst professional male long distance drivers in Lagos, Southwest Nigeria so as to quantify the burden and its predictors.

METHODS

Two hundred and ninety-three drivers were recruited. Details of their socio-demographic characteristics were obtained. Their anthropometric indices, blood pressure, fasting plasma blood glucose and lipid profile were measured. Serum creatinine was measured and estimated glomerular filtration rate, eGFR, was calculated with Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Urinary Albumin Creatinine Ratio (UACR) was determined. A 10 year CVD risk of the subjects was calculated with the Framingham Risk Score (FRS).

RESULTS

Mean age of the study population was 44.8 + 9.7 years. The prevalence of alcohol use and smoking were 71.0 and 19.5% respectively. One hundred and twenty-one (62.8%) of the subjects were either overweight or obese while 70(24.1%) had abdominal obesity. The prevalence of hypertension and diabetes were 39.7 and 13.9% respectively. Prevalence of CKD by eGFR< 60 ml/min/1.73m2 or UACR > 30 mg/g was 51.7% (95% CI; 46.0-57.5). The odds for CKD increased with lower HDL-c levels; OR 3.5 (95% CI, 1.1-11.2; p = 0.03) and longer duration of professional driving > 20 years; OR 2.4(95% CI, 1.5-4.0).

CONCLUSION

Professional male long distance drivers in addition to having very high prevalence of clustering of both CVD and CKD risk factors have a significant burden of asymptomatic CKD. UACR appears to be an earlier marker of CKD in this population. Health awareness promotion and aggressive risk factor reduction are advocated as ways to reduce this burden.

Patient characteristics and initiation of mineralocorticoid receptor antagonists in patients with chronic kidney disease in routine clinical practice in the US: a retrospective cohort study

Background

Steroidal mineralocorticoid receptor antagonists (MRAs) are recommended for the treatment of heart failure (HF) and resistant hypertension, both common comorbidities in patients with diabetes and chronic kidney disease (CKD). This study explored the clinical characteristics of, and steroidal MRA use in, patients with CKD with and without type 2 diabetes mellitus (T2D) and/or HF.

Methods

This retrospective cohort study used PharMetrics Plus US claims database data (October 2009–September 2014) to identify two patient populations aged ≥18 years with a first diagnosis of CKD or a first prescription for steroidal MRAs. Demographic characteristics, comorbidities, clinical events, medication use and healthcare costs were reported by population and stratified by diagnosis: CKD, CKD + T2D (DKD), CKD + HF and DKD + HF. The CKD population cohorts were further stratified by steroidal MRA treatment duration (no MRAs, < 6 and ≥ 6 months’ treatment).

Results

The CKD and MRA populations comprised 229,004 patients and 5899 patients, respectively. Median age and the proportion of men were similar in the CKD and MRA populations across disease cohorts. Disease burden increased across the cohorts as comorbidity and clinical event incidences increased. Hypertension was reported in 70–92% of patients, irrespective of disease cohort or population. In the CKD population, MRA use was low but increased with disease burden: CKD, 1.2%; DKD, 1.8%; CKD + HF, 6.5%; and DKD + HF, 6.6%. Moreover, MRA users presented with higher rates of comorbidities and medication use, and higher healthcare costs than MRA non-users. Longer MRA treatment duration was associated with reduced polypharmacy, lower event rates and lower healthcare costs. In the MRA population, patients almost exclusively received spironolactone (≥ 96%; median dose across all groups 25 mg; one-year persistence, ≤ 43%); up to 16% of patients had end-stage renal disease at baseline despite steroidal MRAs being contraindicated.

Conclusions

Steroidal MRA use was low across all cohorts, but increased with disease severity, driven particularly by HF. Steroidal MRAs were used in patients with advanced CKD, despite being contraindicated. The persistent morbidity and clinical event rates in CKD and DKD patients highlight the disease burden and the need for treatments that effectively target both cardio-vascular and kidney-related events.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1348-4) contains supplementary material, which is available to authorized users.

Obesity Increases the Risk of Postoperative Complications and Revision Rates Following Primary Total Hip Arthroplasty: An Analysis of 131,576 Total Hip Arthroplasty Cases

BACKGROUND

The aim of our study is to evaluate the association of body mass index (BMI) and the risk of postoperative complications, mortality, and revision rates following primary total hip arthroplasty given other potentially confounding patient characteristics in a large cohort study.

METHODS

Using nationwide billing data for inpatient hospital treatment of the biggest German healthcare insurance, 131,576 total hip arthroplasties in 124,368 patients between January 2012 and December 2014 were included. Outcomes were 90-day mortality, 1-year revision procedures (with and without removal or exchange of implants), 90-day surgical complications, 90-day femoral fractures, and overall complications. The effect of BMI on outcome was analyzed using multivariable logistic regression. Risk-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

BMI had a significant effect on overall complications (30-34 in kg/m²: OR 1.1, CI 1.0-1.2, P = .014; 35-39: OR 1.5, CI 1.3-1.6, P < .001; ≥40: OR 2.1, CI 1.9-2.3, P < .001; <30: reference). The OR for 1-year revision procedures (30-34: OR 1.2, CI 1.1-1.4, P = .001; 35-39: OR 1.6, CI 1.4-1.8, P < .001; ≥40: OR 2.4, CI 2.1-2.7, P < .001; <30: reference) and 90-day surgical complications increased with every BMI category. For mortality and periprosthetic fractures there was a higher risk only for patients with BMI ≥40.

CONCLUSION

BMI increases the risk of revision rates in a liner trend. Therefore, the authors believe that patients with a BMI >40 kg/m² should be sent to obesity medicine physicians in order to decrease the body weight prior elective surgery.