Improved renal function 12 months after bariatric surgery

Obesity, kidney and metabolic bariatric surgery: a surgeon’s narrative review

Excess body weight impacts kidney function in individuals with severe obesity, primarily through metabolic alterations in adipocytes, especially in visceral adipose tissue. The relationship between persistent sterile inflammation associated with obesity and the progression of obesity-related kidney disease to chronic kidney disease (CKD) is an area of growing interest. The beneficial effects of weight loss on the prevention of kidney disease and the improvement of kidney function in individuals with obesity have been well documented. Currently, the most effective weight loss strategy is metabolic bariatric surgery (MBS), which has been proven to not only prevent the progression of CKD but also reverse it. However, awareness and understanding of the impact of obesity on the kidney should also extend to the severely obese population with clinically normal renal function. The purpose of this review is to outline the current knowledge on the pathophysiology of obesity-induced kidney damage, the effects of MBS on renal function in severely obese individuals with or without CKD, and provide the current evidence on perioperative management strategies for CKD patients, including diet and nutrition.

New Perspectives on Obesity-Associated Nephropathy from Pathophysiology to Therapeutics: Revealing the Promise of GLP-1 RA Therapy

Obesity represents a substantial risk factor for a multitude of metabolic disorders, which seriously threatens human life and health. As the global obesity epidemic intensifies, obesity-related nephropathy (ORN) has attracted great attention. ORN arises from both physical/mechanical and non-physical insults to the glomerular and tubular structures precipitated by obesity, culminating in structural impairments and functional aberrations within the kidneys. Physical injury factors include changes in renal hemodynamics, renal compression, and mechanical stretching of podocytes. Non-physical injury factors include overactivation of the RAAS system, insulin resistance, lipotoxicity, inflammation, and dysregulation of bile acid metabolism. Exploring molecules that target modulation of physical or nonphysical injury factors is a potential approach to ORN treatment. ORN is characterized clinically by microproteinuria and pathologically by glomerulomegaly, which is atypical and makes early diagnosis difficult. Investigating early diagnostic markers for ORN thus emerges as a critical direction for future research. Additionally, there is no specific drug for ORN in clinical treatment, which mainly focuses on weight reduction, mitigating proteinuria, and preserving renal function. In our review, we delineate a progressive therapeutic approach involving enhancements in lifestyle, pharmacotherapy, and bariatric surgery. Our emphasis underscores glucagon-like peptide-1 receptor agonists (GLP-1 RAs) as poised to emerge as pivotal therapeutic modalities for ORN in forthcoming clinical avenues.

Protective role for kidney TREM2high macrophages in obesity- and diabetes-induced kidney injury

Diabetic kidney disease (DKD), the most common cause of kidney failure, is a frequent complication of diabetes and obesity, and yet to date, treatments to halt its progression are lacking. We analyze kidney single-cell transcriptomic profiles from DKD patients and two DKD mouse models at multiple time points along disease progression-high-fat diet (HFD)-fed mice aged to 90-100 weeks and BTBR ob/ob mice (a genetic model)-and report an expanding population of macrophages with high expression of triggering receptor expressed on myeloid cells 2 (TREM2) in HFD-fed mice. TREM2high macrophages are enriched in obese and diabetic patients, in contrast to hypertensive patients or healthy controls in an independent validation cohort. Trem2 knockout mice on an HFD have worsening kidney filter damage and increased tubular epithelial cell injury, all signs of worsening DKD. Together, our studies suggest that strategies to enhance kidney TREM2high macrophages may provide therapeutic benefits for DKD.

Microvascular complications of obesity and diabetes-Role of bariatric surgery

Bariatric surgery in people with obesity can lead to long-term remission of type 2 diabetes mellitus (T2DM) and a reduction in the incidence of macrovascular complications. The impact of bariatric surgery on microvascular complications is less clear. In this narrative review, we sought to evaluate the effect of bariatric surgery on microvascular complications in patients with and without diabetes. The risk of developing microvascular complications is increased in people with obesity, and this is amplified in those with T2DM. The impact of metabolic surgery on microvascular complications is limited to a subgroup analysis of studies or statistical modeling to predict the glycemia-independent effect of bariatric surgery. While bariatric surgery halts the progression of retinopathy in those with minimal retinopathy, it may worsen in those with advanced retinopathy. Bariatric surgery improves proteinuria and major renal outcomes, regardless of the severity of renal impairment. Bariatric surgery in patients with obesity with or without diabetes is associated with an improvement in neuropathic symptoms and regeneration of small nerve fibers. In conclusion, bariatric surgery is associated with an improvement in microvascular complications. Further studies are needed to elucidate the underlying mechanisms for the favorable effect of bariatric surgery on microvascular outcomes.

Obesity and renal disease: Benefits of bariatric surgery

The prevalence of obesity, a preventable and reversible condition with a high impact on health, continues to rise, especially after the COVID-19 pandemic. Severe overweight is well recognized as a risk factor for diabetes and hypertension, among other conditions, that may increase cardiovascular risk. Obesity has grown simultaneously with a rise in the prevalence of chronic kidney disease, and a pathophysiological link has been established, which explains its role in generating the conditions to facilitate the emergence and maximize the impact of the risk factors of chronic kidney disease and its progression to more advanced stages. Knowing the mechanisms involved and having different tools to reverse the overweight and its consequences, bariatric surgery has arisen as a useful and efficient method, complementary or alternative to others, such as lifestyle changes and/or pharmacotherapy. In a detailed review, the mechanisms involved in the renal consequences of obesity, the impact on risk factors, and the potential benefit of bariatric surgery at different stages of the disease and its progression are exposed and analyzed. Although the observational evidence supports the value of bariatric surgery as a renoprotective measure in individuals with obesity, diabetic or not, randomized studies are expected to establish evidence-based recommendations that demonstrate its positive risk-benefit balance as a complementary or alternative therapeutic tool.

Bariatric Surgery and Solid-Organ Transplantation

Morbid obesity and being overweight are a growing problem worldwide. They also affect patients with end-stage solid-organ disease and patients after transplant. Bariatric surgery is the most effective available weight loss procedure. Bariatric surgery can be helpful for the treatment of some conditions, such as nonalcoholic fatty liver disease or nonalcoholic steatohepatitis, which may lead to transplant, and weight loss can improve or even reverse them. In other cases, morbid obesity is a limitation to accessing a transplant program, so bariatric surgery can serve as a conduit to transplant. After transplant, obesity and obesity-related comorbidities can be a significant health problem that may be treated, as in patients without a transplant, with bariatric surgery. There are some specific conditions and issues to be considered in patients with end-stage solid-organ disease who are candidates for bariatric surgery, such as increased morbidity and mortality. After transplant, immunosuppressant regimens and technical limitations may be also significant.

Anything New in the Treatment of Obesity in Obese Patients with CKD?

Treatment for obesity in patients with CKD englobes a wide range of options, from lifestyle modification to bariatric surgery. Weight loss improves metabolic parameters and stimulates changes in renal function that lead to improvement of glomerular hyperfiltration. The most common clinical presentation is a slowly increasing non-nephrotic proteinuria that is followed by a progressive decline of kidney function. The use of multitarget therapies, with appropriate dietary education, emerging diets, the use of new RAAS blocking agents, the combination of iSGLT2 or GLP-1 agonists, as well as bariatric surgery, may play a key role in finally achieving the desired nephroprotection in this CKD population. New therapeutic agents and novel biomarkers, such as adipocyte cytokines, are needed to monitor and mitigate progression to end-stage renal disease. The emerging "lipidomics" and the role of nonalcoholic fatty liver are relevant research lines.

Perioperative Risks of Sleeve Gastrectomy Versus Roux-en-Y Gastric Bypass Among Patients With Chronic Kidney Disease: A Review of the MBSAQIP Database

OBJECTIVE

To determine whether patients with CKD experience higher rates of perioperative complications after RYGB compared to sleeve gastrectomy.

SUMMARY OF BACKGROUND DATA

For obese CKD patients who qualify for bariatric surgery, sleeve gastrectomy is often preferred to RYGB based on perceptions of prohibitively-high perioperative risks surrounding RYGB. However, some patients with CKD are not candidates for sleeve gastrectomy and the incremental increased-risk from RYGB has never been rigorously tested in this population.

METHODS

CKD patients who underwent RYGB or sleeve gastrectomy between 2015 and 2017 were identified from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program Participant Use File. RYGB patients were 1:1 propensity-score matched with sleeve gastrectomy patients based on preoperative factors that influence operative choice. Primary outcomes included 30-day readmissions, surgical complications, medical complications, and death. Secondary outcomes included the individual complications used to create the composite surgical/medical complications. Univariate logistic regression was used to compare outcomes. E-value statistic was used to test the strength of outcome point estimates against possible unmeasured confounding.

RESULTS

Demographics were similar between RYGB (n = 673) and sleeve gastrectomy (n = 673) cohorts. There were no statistically significant differences in primary outcomes. Among secondary outcomes, only acute kidney injury was statistically-significantly higher among RYGB patients (4.9% vs 2.7%, P = 0.035, E-value 1.27).

CONCLUSIONS

Among well-matched cohorts of RYGB and sleeve gastrectomy patients, incidence of primary outcomes were similar. Among secondary outcomes, only acute kidney injury was statistically-significantly higher among RYGB patients; however, the E-value for this difference was small and relatively weak confounder(s) could abrogate the statistical difference. The perception that RYGB has prohibitively-high perioperative risks among CKD patients is disputable and operative selection should be weighed on patient candidacy and anticipated long-term benefit.

Improvement of Renal Function After Bariatric Surgery: a Systematic Review and Meta-analysis

BACKGROUND/OBJECTIVE

The effect of bariatric surgery in renal function varies and the postoperative benefit time point remains unclear. We aim to assess the changes of renal function after bariatric surgery (BS) in different postoperative periods and subgroups.

METHODS

We searched the databases of PubMed and Cochrane from inception to December 14, 2020. Articles included in the study were drawn from all recipients of BS that provided assessments of renal function pre and post-surgery. Meta-analysis was performed to compare glomerular filtration rate (GFR), serum creatinine, albumin-to-creatinine ratio (ACR), and albuminuria before and after BS.

RESULTS

The study included 49 articles involving 8515 patients. Compared with pre-operative renal function, the overall analysis showed that bariatric surgery significantly reduced serum creatinine levels, ACR, and albuminuria. There was significant increase of GFR in the CKD subgroup, yet a noticeable decrease in the hyperfiltration subgroup. The most significant improvement in GFR was seen 6-12 months after BS, while ACR dropped most dramatically 12-24 months after BS.

CONCLUSIONS

Bariatric surgery can improve renal function in obese patients with kidney dysfunction, especially 1 year after surgery.

Improvement of kidney function in patients with chronic kidney disease and severe obesity after bariatric surgery: A systematic review and meta-analysis

The general management for chronic kidney disease (CKD) includes treating reversible causes, including obesity, which may be both a driver and comorbidity for CKD. Bariatric surgery has been shown to reduce the likelihood of CKD progression and improve kidney function in observational studies. We performed a systematic review and meta-analysis of patients with at least stage 3 CKD and obesity receiving bariatric surgery. We searched Embase, MEDLINE, CENTRAL and identified eligible studies reporting on kidney function outcomes in included patients before and after bariatric surgery with comparison to a medical intervention control if available. Risk of bias was assessed with the Newcastle-Ottawa Risk of Bias score. Nineteen studies were included for synthesis. Bariatric surgery showed improved eGFR with a mean difference (MD) of 11.64 (95%CI: 5.84 to 17.45, I²  = 66%) ml/min/1.73m² and reduced SCr with MD of -0.24 (95%CI -0.21 to -0.39, I²  = 0%) mg/dl after bariatric surgery. There was no significant difference in the relative risk (RR) of having CKD stage 3 after bariatric surgery, with a RR of -1.13 (95%CI: -0.83 to -2.07, I²  = 13%), but there was reduced likelihood of having uACR >30 mg/g or above with a RR of -3.03 (95%CI: -1.44 to -6.40, I²  = 91%). Bariatric surgery may be associated with improved kidney function with the reduction of BMI and may be a safe treatment option for patients with CKD. Future studies with more robust reporting are required to determine the feasibility of bariatric surgery for the treatment of CKD.

Metabolic surgery in China: present and future

Obesity and its related complications comprise a serious public health problem worldwide, and obesity is increasing in China. Metabolic surgery is a new type of treatment with unique advantages in weight loss and obesity-related metabolic complications. The pathogenesis of obesity is complex and not yet fully understood. Here, we review the current efficacy and safety of metabolic surgery, as well as recent progress in mechanistic studies and surgical procedures in China. The exciting and rapid advances in this field provide new opportunities for patients with obesity and strike a balance between long-term effectiveness and safety.

The Impact of Bariatric Surgery on Renal Function: a Retrospective Analysis of Short-Term Outcomes

PURPOSE

Obesity and diabetes mellitus are now leading causes of chronic kidney disease. Our study investigated the effects of bariatric surgery on estimated glomerular filtration (eGFR) and urinary microalbumin/creatinine ratio (ACR) in morbidly obese patients.

MATERIALS AND METHODS

The clinical materials for patients who underwent bariatric surgery were retrospectively analyzed with a 6-month follow-up period between January 1, 2018, and June 1, 2020. The eGFR (ml/min) was calculated using the Cockcroft-Gault formula equation. The urinary ACR was measured during the follow-up. Body mass index (BMI, kg/m²), percent weight loss (%WL), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were recorded during the follow-up.

RESULTS

Sixty-one patients who underwent bariatric surgery-laparoscopic Roux-en-Y gastric bypass (LRYGB; n = 22) and laparoscopic sleeve gastrectomy (LSG; n = 39)-were included in this study. The eGFR of both groups decreased at the follow-up outpatient visits (p < 0.001), although eGFR did not differ between the two groups. Unexpectedly, the ACR increased in the first month after LSG (p < 0.01) but decreased with a descending trend with no significant difference (p > 0.05) throughout the remaining follow-up period. Interestingly, ACR showed a descending trend with no significant difference during the follow-up in the LRYGB group (p > 0.05). The SBP and DBP decreased after bariatric surgery, with no significant difference between the two groups (p > 0.05).

CONCLUSION

Bariatric surgery is associated with improvements in postoperative renal function 6 months following surgery. The different alterations in ACR following LSG and LRYGB procedures demonstrate the underlying mechanism.

The Relationship Between Preoperative Kidney Function and Weight Loss After Bariatric Surgery in Patients with Estimated Glomerular Filtration Rate ≥ 30 mL/min: Tehran Obesity Treatment Study

INTRODUCTION

Severe obesity can lead to progressive kidney injury and chronic kidney disease (CKD). The current study aimed at determining whether preoperative kidney function level in patients with estimated glomerular filtration rate (eGFR) ≥30 mL/min affects weight loss after bariatric surgery.

METHODS

A total of 1958 bariatric patients underwent laparoscopic sleeve gastrectomy and gastric bypass from March 2013 to March 2017. The patients were categorized according to preoperative eGFR (30-59, 60-89, 90-124, and ≥ 125 mL/min). Changes in body mass index (BMI), percentage of total weight loss (TWL%), and percentage of excess weight loss (EWL%) were compared across the eGFR categories. Moreover, multivariable logistic regression analysis was used to evaluate the relationship between eGFR and insufficient weight loss (defined as not achieving 50% EWL at 12 months after surgery).

RESULTS

Preoperative eGFR was positively associated with unadjusted ΔBMI (P trend < 0.001), TWL% (P trend < 0.001), and EWL% (P trend = 0.007) after 12 months of surgery. However, these associations were no longer significant after multivariable adjustment. Further, univariate analysis demonstrated a positive relationship between preoperative eGFR and insufficient weight loss (odds ratio [OR] 1.38; 95% confidence interval [CI] 1.11-1.71; P = 0.004). By contrast, preoperative eGFR was not a predictor of insufficient weight loss in multivariable logistic regression analysis (OR 0.98; 95% CI 0.46-1.24; P = 0.886).

CONCLUSION

Although patients with lower preoperative eGFR experience less weight loss after bariatric surgery, preoperative kidney function does not appear to have an independent impact on postoperative weight loss in patients with eGFR ≥ 30 mL/min.

Association of Serum Zinc Concentration with Preservation of Renal Function After Bariatric Surgery: a Retrospective Pilot Study

BACKGROUND

Although serum zinc level (Zn) is known to impact renal function in patients with diabetes, their correlation following bariatric surgery remains unknown. This study aimed at assessing the association of Zn with estimated glomerular filtration rate (eGFR) after laparoscopic sleeve gastrectomy (LSG).

METHODS

One hundred and twenty-nine patients in total (mean age, 38.1 ± 10.8; body mass index, 39.1 ± 5.1 kg/m²) with normal preoperative kidney function undergoing LSG at a single tertiary referral center were reviewed. The primary study endpoint was the relationship between Zn and post-LSG eGFR at 12-month follow-up. The secondary outcomes were the associations of percentage weight loss (%WL) with changes in Zn (△Zn) and eGFR (△eGFR).

RESULTS

The incidence of zinc deficiency was 8.5%, 8.1%, and 29.9% at baseline, post-LSG and one- and 12-month follow-up, respectively. At 12-month follow-up, Zn dropped from 104.1 ± 19.2 to 85.3 ± 38.9 μg/dL (p = 0.001), while eGFR levels decreased from 106.6 ± 10.3 to 102.1 ± 19.4 mL/min per 1.73 m² (p = 0.025). Zn correlated positively with eGFR at 6-month (r = 0.252, p = 0.037) and 12-month (r = 0.41, p = 0.001) follow-ups. Multiple linear regression analyses including baseline variables of age, sex, BMI, %WL, and diabetes identified Zn and %WL as independent predictors of eGFR at 12-month follow-up. There was no evidence of multicollinearity among these variables. Despite positive association between %WL and △eGFR (r = 0.222, p = 0.031), no correlation was noted between %WL and △Zn (r = - 0.129, p = 0.40).

CONCLUSION

The results demonstrated a positive relationship between post-LSG serum zinc levels and preservation of renal function among patients with obesity in a surgical setting. Large-scale studies are warranted to support the findings.

Comparison of eGFR formulas in determining chronic kidney disease stage in bariatric patients and the impact on perioperative outcomes

BACKGROUND

Chronic kidney disease (CKD) independently increases the risk of 30-day adverse outcomes following metabolic and bariatric surgery (MBS). However, no studies have evaluated the stage of CKD at which increased perioperative risk is manifested. Here, we correlate 30-day major morbidities after MBS with extent of renal disease based on CKD Stage.

OBJECTIVES

To determine the impact of CKD stage on perioperative outcomes after bariatric surgery.

SETTING

Academic Hospital.

METHODS

From the 2017 Metabolic and Bariatric Surgery Quality Improvement Program (MBSAQIP) database, we identified patients with CKD who underwent sleeve gastrectomy or laparoscopic gastric bypass surgery. Glomerular filtration rates (GFRs) were calculated and cohorts were generated based on CKD Stage. Complication rates and rates of morbidity and mortality were compared between stages, and strengths of correlation were calculated.

RESULTS

GFR and CKD Stage were calculated for 150,283 patients. There was a significant increase in the risk of major morbidity at each progressive stage of CKD (P < .001 for all compared stages). There was a strong positive linear correlation between increasing CKD Stage and total morbidity (r² = .983), including reoperation ( r² = .784), readmission (r² = .936), unplanned ICU transfer (r² = .853), and aggregate complications such as pulmonary (r² = .900), bleeding (r² = .878), or progressive worsening of renal function (r² = .845). In logistic regression, for every 10-point decrease in GFR, odds of total morbidity increased by 6%.

CONCLUSION

An increased risk of perioperative complications may be seen in early stages of CKD, and risk is compounded in more advanced stages. Bariatric surgical candidates should be counseled on their increased risk of surgical complications even with mild CKD, and the benefits of bariatric surgery should be carefully weighed against significantly increased risks of complications in severe CKD.

Bariatric Surgery Is Protective Against Renal Function Decline in Severely Obese Patients in the Long-Term

PURPOSE

This study aims to assess the long-term renal effects of bariatric surgery (BS) in severely obese patients over a follow-up period of up to 11 years.

MATERIALS AND METHODS

In a retrospective cohort study including 102 patients, patients were stratified by eGFR at baseline and divided into three groups: (1) reduced, (2) normal, and (3) increased filtration rate. Adjustments for age- and sex-related decline in eGFR were performed. We used uni- and multivariate regression analysis to identify variables that were thought to determine change in eGFR.

RESULTS

Over a median follow-up of 8.5 years (interquartile range 2.7), eGFR declined from 96.1 ± 20.7 to 84.9 ± 21.0 ml/min (p < 0.001). Among patients with (1), eGFR remained stable (69.1 ± 19.3 ml/min). Among patients with (2), eGFR declined from 99.7 ± 13.3 ml/min to 88.7 ± 19.4 ml/min (p < 0.001). Among patients with (3), eGFR decreased to normal levels (94.2 ± 17.7 ml/min, p < 0.001). Age- and sex-adjusted eGFR increased (6.4 ± 14.4 ml/min; p < 0.05) among patients with reduced filtration rate. Among patients with normal filtration rate, adjusted eGFR remained stable during follow-up (-1.3 ± 15.2 ml/min; n.s.). Among patients with increased filtration rate, adjusted eGFR decreased and remained within the normal range (-13.2 ± 12.2 ml/min; p < 0.001). Change in eGFR showed a negative correlation with eGFR at baseline (B = -0.31; p < 0.001), change in LDL-cholesterol (B = -0.09; p < 0.05), and a negative correlation with treatment requiring hypertension (B = -9.36; p = 0.001).

CONCLUSION

BS is protective against renal function decline in severely obese patients in the long term.

Comparative Effectiveness of Roux-en-Y Gastric Bypass vs. One Anastomosis Gastric Bypass on Kidney Function

PURPOSE

Obesity and its associated medical problems increase risk of kidney function decline while prior studies suggest that bariatric surgery may improve kidney outcomes. However, little is known about the comparative effectiveness of different types of bariatric surgery on kidney function. In this study, we compare the effects of laparoscopic one anastomosis gastric bypass (LOAGB) and laparoscopic Roux-en-Y gastric bypass (LRYGB) on kidney function one year after surgery.

MATERIALS AND METHODS

The patients' demographic, medical, and surgical data were prospectively collected and retrospectively reviewed. Type 2 diabetes mellitus, hypertension, and dyslipidemia, body mass index (BMI), and kidney function tests were obtained before and one year after surgery. Kidney function was evaluated by estimated glomerular filtration rate (eGFR) and spot urine albumin to creatinine ratio (ACR). Changes in eGFR and ACR were compared between LRYGB vs. LOAGB after adjustment for confounders (age, sex, remission of associated medical problems, preoperative BMI, and percentage of excess BMI loss) using ANCOVA model.

RESULTS

Both surgical techniques significantly decreased the post-surgery presence of diabetes, hypertension, and dyslipidemia (p < 0.001 for all paired comparisons). The eGFR level significantly increased and the ACR level significantly decreased in both groups (p < 0.001 for all paired comparisons before and after adjustment). However, eGFR and ACR mean differences between LRYGB and LOAGB were not significantly different after adjustment for confounding variables (p = 0.9 and 0.4, respectively).

CONCLUSION

Both LOAGB and LRYGB improved 1-year eGFR and ACR equally independently from weight loss and other confounders.

Impact of Preoperative Anemia on Postoperative Kidney Function Following Laparoscopic Bariatric Surgery

BACKGROUND

Preoperative anemia is a risk factor for acute kidney failure after high-risk surgeries. We assessed the impact of preoperative anemia on kidney function in an obese Asian population after laparoscopic bariatric surgery.

METHODS

Patient characteristics, comorbidities, type of surgery, perioperative profiles, eGFR, and micronutrition were retrospectively reviewed in 341 patients with obesity undergoing bariatric surgery. All patients, who had a preoperative estimated glomerular filtration rates (eGFR) ≥ 90 mL/min/1.73 m², were followed for 1 year and assigned to one of two groups: anemia or non-anemia group. Preoperative anemia was determined based on hemoglobin concentration.

RESULTS

The Pearson's correlation coefficient between preoperative body mass index (BMI) and preoperative eGFR of all patients was 0.169 (p = 0.005). Preoperatively, there were no significant differences in age, BMI, and eGFR between the anemia (n = 38) and non-anemia groups (n = 303). Patients in the anemia group had lower hemoglobin concentration at baseline, 1 month, and 12 months after surgery than those in the non-anemia group. Postoperative eGFR levels at 1 month (p = 0.993) and 1 year (p = 0.118) as well as hospital stay (p = 0.941) were comparable between the two groups. However, the percentage weight loss was significantly higher in the non-anemia group than that in the anemia group 1 year after bariatric surgery (30.0 ± 7.3% vs. 27.0 ± 8.1%; p = 0.041).

CONCLUSIONS

Preoperative anemia did not negatively impact kidney function following laparoscopic bariatric surgery during the 12-month follow-up. Considering the potential adverse impact of anemia on postoperative weight loss, preoperative correction of anemia may be recommended.

Reduction in Urinary Chemokine (C-C Motif) Ligand 2 (CCL2) After Surgery-Induced Weight Loss

Kidney dysfunction, a deleterious effect of obesity, is now recognized as a relevant health risk. Chemokine (C-C Motif) Ligand 2 (CCL2) is one of the critical chemokines that play a vital role in the development of obesity-related metabolic disease. We aim to measure the changes in urinary CCL2 in our patients before and after their bariatric procedure and examine the correlation between CCL2 and renal function. A prospective cohort study was conducted at our teaching university hospital. Ethics approval was obtained from our institutional review board. Patients with a BMI of ≥37.5 kg/m² with no history of renal disease were included. They underwent single anastomosis gastric bypass (SAGB), Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG), all performed via laparoscopic approach. Venous blood and urine samples were obtained preoperatively and six months after surgery. A total of 58 patients were recruited, with SG being performed in 74.1% of patients. At six-months follow-up, median (IQR) body weight reduced from 101.35 kgs (20.25) to 76.95 kg (24.62) p < 0.001. The mean (SD) estimated glomerular filtration rate (eGFR) improved from 96.26 ± 14.97 to 108.06 ± 15.00 mL/min/1.73 m², p < 0.001. The median (IQR) urinary CCL2 levels reduced from 15.2 pg/ml (10.77) to 4.30 pg/ml (4.27) p < 0·001. There is a significant correlation between the reduction of BMI and the reduction of urinary CCL2 (r = −0.220, p = 0.048). We also found a significant correlation between the reduction of urinary CCL2 with the reduction of urine ACR (r = −0.240, p = 0.035). Urinary CCL2 is a promising biomarker that can be used to assess improvement in renal function in obese patients after bariatric surgery.

Impact of serum uric acid on renal function after bariatric surgery: a retrospective study

BACKGROUND

Despite a known negative association between serum uric acid level (SUA) and renal function, this correlation in patients after bariatric surgery remains unknown.

OBJECTIVE

To assess correlation between postoperative SUA and estimated glomerular filtration rate (eGFR) at 12 months after bariatric surgery.

SETTING

A single tertiary referral center.

METHODS

A total of 252 patients (age = 40.5 ± 11.2; body mass index = 39.0 ± 5.5 kg/m²) undergoing bariatric surgery divided into 2 groups (i.e., normal renal function [90 ≤ eGFR < 125 mL/min/1.73 m², n = 176] versus renal function impairment [eGFR < 90 mL/min/1.73 m², n = 76]) were assessed for relationships between SUA and eGFR in both groups (primary endpoint) and associations of percentage weight loss with changes in SUA (△SUA) and eGFR (△eGFR) for all patients (secondary endpoint) at 12 months.

RESULTS

Overall, prevalence of hyperuricemia was 40.4% and 22.2% (baseline and postoperative 12 mo, respectively). Reverse relationship was observed between SUA and eGFR (r = -.152, P = .007) for all patients with no association noted between baseline SUA and eGFR in each group as well as between SUA and eGFR at 12 months in the normal group (r = -.076, P = .437). The reverse relationship was found (r = -.417, P = .005) in renal function impairment group for whom SUA was identified as a predictor of eGFR at 12 months. There was no association of percentage weight loss with △SUA (r = .089, P = .601) and △eGFR (r = -.046, P = .785).

CONCLUSION

The results demonstrated a negative relationship between postoperative SUA and renal function in patients with preexisting renal dysfunction undergoing bariatric surgery. Clinical significance of our findings warrants further investigation.

The Effects of Bariatric Surgery on Renal Outcomes: a Systematic Review and Meta-analysis

BACKGROUND/OBJECTIVE

Although promising, data regarding the renal impact and safety of bariatric surgery (BS) are insufficient. We aimed at investigating the benefits and harms of BS for weight loss on kidney function.

METHODS

A systematic review and meta-analysis of observational studies reporting data about the impact of BS (any techniques) on serum/plasma creatinine, creatinine clearance, glomerular filtration rate (GFR), proteinuria, nephrolithiasis, and need for renal replacement therapy (RRT)) was performed. Obese adults (non-chronic kidney disease (CKD), CKD or transplanted patients) that underwent BS for weight loss were included. After searching MEDLINE (inception to August 2017), the Cochrane Library (Issue 10-12, October 2017), and the websiteclinicaltrials.gov (August 2017), data were extracted and summarized using a random-effects model.

RESULTS

The final analysis included 23 cohort studies, comprising 3015 participants. Compared with renal function before treatment, BS significantly decreased serum creatinine level (mean difference (MD), - 0.08 mg dl^-1; 95% confidence interval (CI), - 0.10 to - 0.06); p < 0.001) and proteinuria (MD, - 0.04 g 24 h^-1; 95% CI, - 0.06 to - 0.02; p < 0.001) in the overall group. GFR significantly improved 6 months or more after BS both in the hyperfiltration and CKD subgroups. Renal function also tended to improve in renal transplant patients. Data on nephrolithiasis and the need for RRT were scarce or not reported.

CONCLUSIONS

BS apparently has positive effects on kidney function and tends to normalize GFR across different categories of renal impairment (hyperfiltration and CKD patients).

Nutritional Management for Chronic Kidney Disease Patients who Undergo Bariatric Surgery: A Narrative Review

Bariatric surgery (BS) may be effective for chronic kidney disease (CKD) patients by reducing microalbuminuria and proteinuria, and by facilitating their meeting inclusion criteria for kidney transplantation. However, nutritional management for this population is complex and specific guidelines are scarce. A literature search was performed to create dietetic practice for these patients based on the most recent evidence. For the purposes of nutritional recommendations, we divided the patients into 2 subgroups: 1) patients with CKD and dialysis, and 2) patients after kidney transplantation. Before surgery, nutritional care includes nutritional status evaluation and adjusting doses of supplements to treat deficiencies and daily nutrient intake according to the dietary restrictions derived from kidney disease, including quantities of fluids, protein, phosphorus, potassium, and vitamins. After BS, these patients are at major risk for lean body mass loss, malnutrition and dehydration because of fluid restriction and diuretics. Postoperative nutritional recommendations should be carefully tailored according to CKD nutritional limitations and include specific considerations regarding protein, fluids, and supplementation, in particular calcium, vitamin A, and vitamin D. Nutritional management of CKD and kidney transplant patients undergoing BS is challenging and future studies are required to establish uniform high-level evidence-based guidelines.

Renal experiences of bariatric surgery in patients with type 2 diabetes mellitus

The review addresses the questions of the literature devoted to the problem of the influence of bariatric surgery on the course of diabetic nephropathy in patients with diabetes mellitus type 2 after achieving a surgically induced remission. This approach was shown to have positive aspects, such as decrease in creatinine, decrease in albuminuria, an increase in GFR, normalization of glycemia and blood pressure, "incretin effect"'s influence on the kidneys. Descriptions of the currently expected pathogenetic mechanisms involved in achieving the observed improvement in microvascular complications of diabetes, namely diabetic kidney disease, are also described in details.

Longitudinal assessment of renal function in native kidney after bariatric surgery

The epidemic of obesity parallels that of chronic kidney disease (CKD). Obesity worsens the course of CKD, mainly defined by an abnormal glomerular filtration rate (GFR). Patients with severe obesity stages (II and III with body mass index >35 kg/m²) are eligible for bariatric surgery (BS), which is the most efficient method of achieving durable weight loss. BS may reverse glomerular hyperfiltration and albuminuria, improve adipocytokine profile, and relieve diabetes and hypertension. Obesity remission after BS might prevent the progression of renal failure in populations with morbid obesity. However, evidence for the beneficial effect of BS on renal function is scant. This lack of knowledge is mainly due to methodologic reasons, which are addressed in this review. The reversibility of hyperfiltration due to the presence of functional renal reserve hampers the interpretation of changes in true GFR after BS. This true GFR is only obtained with the renal clearance of an exogenous filtration marker. Estimation of GFR is generally provided by prediction equations, namely by modification of diet in renal diseases or by chronic kidney disease-epidemiology collaborative group. These equations are not accurate because the serum levels of both creatinine and cystatin C depend on extrarenal factors, which are modified by BS. Comparing the slopes of measured GFR according to various durations of exposure with morbid obesity would be critical in providing reliable data. Herein, we review the current knowledge on the effects of BS on kidney function; we specify the methodologic issues and particularities of the dietary management of CKD patients to propose reliable directions for future clinical research.

Associations between body mass index and the risk of renal events in patients with type 2 diabetes

BACKGROUND/OBJECTIVES

We aimed to evaluate the relationship between BMI and the risk of renal disease in patients with type 2 diabetes in the Action in Diabetes and Vascular Disease: PreterAx and DiamicroN Modified-Release Controlled Evaluation (ADVANCE) study.

SUBJECTS/METHODS

Participants were divided into six baseline BMI categories: <18.5 (underweight, n = 58); ≥18.5 to <25 (normal, n = 2894); ≥25 to <30 (overweight, n = 4340); ≥30 to <35 (obesity grade 1, n = 2265); ≥35 to <40 (obesity grade 2, n = 744); and ≥40 kg/m2 (obesity grade 3, n = 294); those underweight were excluded. The composite outcome "major renal event" was defined as development of new macroalbuminuria, doubling of creatinine, end stage renal disease, or renal death. These outcomes and development of new microalbuminuria were considered individually as secondary endpoints.

RESULTS

During 5-years of follow-up, major renal events occurred in 487 (4.6%) patients. The risk increased with higher BMI. Multivariable-adjusted HRs (95% CIs), compared to normal weight, were: 0.91 (0.72-1.15) for overweight; 1.03 (0.77-1.37) for obesity grade 1; 1.42 (0.98-2.07) for grade 2; and 2.16 (1.34-3.48) for grade 3 (p for trend = 0.006). These findings were similar across subgroups by randomised interventions (intensive versus standard glucose control and perindopril-indapamide versus placebo). Every additional unit of BMI over 25 kg/m2 increased the risk of major renal events by 4 (1-6)%. Comparable results were observed with the risk of secondary endpoints.

CONCLUSIONS

Higher BMI is an independent predictor of major renal events in patients with type 2 diabetes. Our findings encourage weight loss to improve nephroprotection in these patients.

Renal Metabolic Programming Is Linked to the Dynamic Regulation of a Leptin-Klf15 Axis and Akt/AMPKα Signaling in Male Offspring of Obese Dams

Childhood obesity is associated with renal diseases. Maternal obesity is a risk factor linked to increased adipocytokines and metabolic disorders in the offspring. Therefore, we studied the impact of maternal obesity on renal-intrinsic insulin and adipocytokine signaling and on renal function and structure. To induce maternal obesity, female mice were fed a high-fat diet (HFD) or a standard diet (SD; control group) prior to mating, during gestation, and throughout lactation. A third group of dams was fed HFD only during lactation (HFD-Lac). After weaning at postnatal day (P)21, offspring of all groups received SD. Clinically, HFD offspring were overweight and insulin resistant at P21. Although no metabolic changes were detected at P70, renal sodium excretion was reduced by 40%, and renal matrix deposition increased in the HFD group. Mechanistically, two stages were differentiated. In the early stage (P21), compared with the control group, HFD showed threefold increased white adipose tissue, impaired glucose tolerance, hyperleptinemia, and hyperinsulinemia. Renal leptin/Stat3-signaling was activated. In contrast, the Akt/ AMPKα cascade and Krüppel-like factor 15 expression were decreased. In the late stage (P70), although no metabolic differences were detected in HFD when compared with the control group, leptin/Stat3-signaling was reduced, and Akt/AMPKα was activated in the kidneys. This effect was linked to an increase of proliferative (cyclinD1/D2) and profibrotic (ctgf/collagen IIIα1) markers, similar to leptin-deficient mice. HFD-Lac mice exhibited metabolic changes at P21 similar to HFD, but no other persistent changes. This study shows a link between maternal obesity and metabolic programming of renal structure and function and intrinsic-renal Stat3/Akt/AMPKα signaling in the offspring.

Bariatric surgery is associated with renal function improvement

INTRODUCTION

Weight loss after bariatric surgery improves both blood pressure and glycemic control following surgery. The effect of bariatric surgery on renal function is not well characterized. In this study, we sought to quantify the change in renal function over time following surgery.

METHODS

We retrospectively reviewed all patients who underwent laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) between 2012 and 2014 at our institution. The glomerular filtration rate (GFR, mL/min) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Body mass index (BMI, kg/m²) and percent weight loss (%WL) were calculated following the surgery.

RESULTS

A total of 149 patients who underwent bariatric surgery were included in this study: LRYGB (n = 86 and LSG (n = 63). In LRYGB group, baseline BMI (kg/m², ±SD) and GFR (mL/min, ±SD) were 48.5 ± 6.8 and 94.7 ± 23.8, respectively. In comparison, BMI and GFR were 49.1 ± 11.9 kg/m² and 93.1 ± 28.0 mL/min in the LSG group, respectively. Over the follow-up period (19.89 ± 10.93 months), the patients who underwent LRGYB lost a larger percentage of weight as compared to those in the LSG group (29.9 ± 11.7% vs 22.3 ± 10.7%; p = <0.0001). Overall, GFR improved in both LRYGB (101.0 ± 25.8 mL/min) and LSG groups (97.9 ± 25.8 mL/min) and was not significantly different between the two groups. Of patients with a GFR < 90 mL/min prior to weight loss surgery (n = 62), 42% had improvement of their GFR to > 90 mL/min postoperatively (p < 0.001). There was no relationship between weight loss percentage and GFR improvement (p = 0.8703).

CONCLUSIONS

Bariatric surgery was associated with improvement in postoperative renal function at almost two years following surgery but was not different for LRYGB versus LSG. The gain in GFR was independent of percentage of weight lost suggesting an alternate mechanism in the improvement of renal function other than weight loss alone.

Determinants of glomerular filtration rate following bariatric surgery in individuals with severe, otherwise uncomplicated, obesity: an observational, prospective study

AIMS

Obesity-induced nephropathy is an established clinical entity arising from a "maladaptive" response to lipid accumulation at the nephron level. Bariatric surgery positively affects renal function, reducing or increasing glomerular filtration rate (GFR) in subjects with hyperfiltration and renal impairment, respectively. The effect of this surgery in patients with normal estimated GFR (eGFR) is less clear.

METHODS

A complete clinical and biochemical assessment of 135 severely obese, otherwise healthy subjects, was obtained before Roux-en-Y gastric bypass (RYGB). All subjects underwent an OGTT with plasma glucose and insulin determinations. Follow-up data were recorded at 6, 12, 24 and 48 months after intervention.

RESULTS

Baseline eGFR was 98.2 ± 13.6 ml/min/1.73 m²; hyperfiltration (>120 ml/min/1.73 m²) was present in 7% of the cohort. No eGFR variation over the follow-up emerged, except at the last visit (-3.6 ± 1.4 ml/min/1.73 m² at month 48, p = 0.01 vs baseline). In the univariate analysis, the renal performance at 48 months was inversely related to baseline eGFR (r = -0.17, p = 0.04) and plasma triglycerides (r = -0.04, p = 0.05). Fasting and OGTT-derived variables did not impact eGFR. By multiple regression analysis, eGFR time course was independently predicted only by baseline eGFR (p = 0.03). Interestingly, patients having a baseline eGFR >100 ml/min/1.73 m² (median value) showed, after 48 months, an average loss of -8.3 ± 2.2 ml/min/1.73 m², while those with eGFR <100 exhibited a slight increase (+1.8 ± 2.3 ml/min/1.73 m², p < 0.01).

CONCLUSIONS

Long-term data confirm the safety of RYGB on renal function. Interestingly, a subtle hyperfiltration, i.e., occurring in high-normal range of eGFR, is attenuated by surgical procedure. Lastly, high serum triglycerides may track an unfavorable renal outcome.

The dual roles of obesity in chronic kidney disease: a review of the current literature

PURPOSE OF REVIEW

Obesity is a major risk factor for the development of de novo chronic kidney disease (CKD). However, once kidney disease is acquired, obesity is paradoxically linked with greater survival, especially in those with advanced CKD. This review examines current evidence for obesity as a risk factor for incident CKD, studies of obesity and mortality across various CKD populations, and potential mechanisms underlying the 'obesity paradox' in kidney disease.

RECENT FINDINGS

Large cohort studies show that overweight body habitus, especially in the context of metabolic syndrome, is associated with higher risk of incident CKD. Emerging data also suggest weight-loss interventions retard or reverse early CKD progression, whereas in hemodialysis patients weight-loss paradoxically heralds poor outcomes. Although the pathogenesis of CKD in obesity remains unclear, studies indicate that excess body fat leads to kidney disease via indirect and direct mechanisms. Meta-analyses suggest that overweight and obese BMI ranges are counterintuitively associated with lower mortality in advanced predialysis and dialysis-dependent CKD patients, whereas a pooled analysis observed that higher pretransplantation BMI was associated with higher mortality in kidney transplantation recipients.

SUMMARY

In addition to its role as a risk factor for de novo CKD, there appears to be a consistent association between obesity and lower mortality in those with established CKD, particularly among hemodialysis patients, suggesting that the reverse epidemiology of obesity is biologically plausible.

Insights from Screening a Racially and Ethnically Diverse Population for Chronic Kidney Disease

BACKGROUND

The value of chronic kidney disease (CKD) screening in the general population remains unclear but may be beneficial in populations with high disease prevalence. We examined risk factors for albuminuria among participants in a state-wide CKD screening program in Hawaii.

METHODS

The National Kidney Foundation of Hawaii Kidney Early Detection Screening (NKFH-KEDS) program held 19 CKD screening events from 2006 to 2012. Participants rotated through 5 stations during which sociodemographic, blood glucose, urine albumin-to-creatinine ratio (ACR), and spot urine albumin data were collected. Multivariate logistic regression analyses (adjusted for age, sex, race/ethnicity, body mass index [BMI]) were used to identify clinical predictors of abnormal ACR (≥30 μg/mg) and abnormal spot urine albumin (>20 mg/L) levels.

RESULTS

Among 1,190 NKFH-KEDS participants who met eligibility criteria, 13 and 49% had abnormal ACR and urine albumin levels, respectively. In multivariate logistic regression analyses, participants of older age (>65 years), Asian and Pacific Islander race/ethnicity, BMI ≥30 kg/m2, and with hypertension had higher risk of abnormal ACR. Being of older age; Asian, Pacific Islander, and Mixed race/ethnicity; and having diabetes was associated with higher risk of abnormal urine albumin levels in adjusted analyses.

CONCLUSIONS

NKFH-KEDS participants of older age; Asian and Pacific Islander race/ethnicity; and with obesity, hypertension, and diabetes had higher risk of kidney damage defined by elevated ACR and urine albumin levels. Further studies are needed to determine whether targeted screening programs can result in timely identification of CKD and implementation of interventions that reduce cardiovascular disease, death, and progression to end-stage renal disease.

Effects of Bariatric Surgery on Renal Function in Obese Patients: A Systematic Review and Meta Analysis

Background

Obesity is an independent risk factor of development and progression of chronic kidney disease (CKD). Data on the benefits of bariatric surgery in obese patients with impaired kidney function have been conflicting.

Objective

To explore whether there is improvement in glomerular filtration rate (GFR), proteinuria or albuminuria after bariatric surgery.

Methods

We comprehensively searched the databases of MEDLINE, Embase, web of science and Cochrane for randomized, controlled trials and observational studies that examined bariatric surgery in obese subjects with impaired kidney function. Outcomes included the pre- and post-bariatric surgery GFR, proteinuria and albuminuria. In obese patients with hyperfiltration, we draw conclusions from studies using measured GFR (inulin or iothalamate clearance) unadjusted for BSA only. Study quality was evaluated using the Newcastle-Ottawa Scale.

Results

32 observational studies met our inclusion criteria, and 30 studies were included in the meta-analysis. No matter in dichotomous data or in dichotomous data, there were statistically significant reduction in hyperfiltration, albuminuria and proteinuria after bariatric surgery.

Limitations

The main limitation of this meta-analysis is the lack of randomized controlled trials (RCTs). Another limitation is the lack of long-term follow-up.

Conclusions

Bariatric surgery could prevent further decline in renal function by reducing proteinuria, albuminuria and improving glomerular hyperfiltration in obese patients with impaired renal function. However, whether bariatric surgery reverses CKD or delays ESRD progression is still in question, large, randomized prospective studies with a longer follow-up are needed.

The impact of bariatric surgery on estimated glomerular filtration rate in patients with type 2 diabetes: a retrospective cohort study

BACKGROUND

Diabetes mellitus is the most common cause of end-stage renal disease, which is associated with increased morbidity and mortality. The impact of bariatric surgery on chronic kidney disease is unclear.

OBJECTIVES

Our primary aim was to assess the impact of bariatric surgery on estimated glomerular filtration rate (eGFR) in type 2 diabetes (T2D) patients. Our secondary aim was to compare the impact of bariatric surgery versus routine care on eGFR in patients with T2D.

SETTING

University Hospital, United Kingdom.

METHODS

A retrospective cohort analysis of adults with T2D who underwent bariatric surgery at a single center between January 2005 and December 2012. Data regarding eGFR were obtained from electronic patients records. eGFR was calculated using the Modification of Diet in Renal Disease formula. Data regarding patients with T2D who did not undergo bariatric surgery ("routine care") were obtained from patients attending the diabetes clinic at the same center from 2009 to 2011.

RESULTS

One hundred sixty-three patients were included (mean age 48.5±8.8 yr; baseline body mass index 50.8±9.1 kg/m²) and were followed for 3.0±2.3 years. Bariatric surgery resulted in an improvement in eGFR (median [interquartile range] 86.0 [73.0-100.0] versus 92.0 [77.0-101.0] mL/min/1.73 m² for baseline versus follow-up, respectively; P = .003), particularly in patients with baseline eGFR≤60 mL/min/1.73 m² (48.0 [42.0-57.0] versus 61.0 [55.0-63.0] mL/min/1.73 m²; P = .004). After adjusting for baseline eGFR, glycated hemoglobin (HbA1C), body mass index, age, and gender, bariatric surgery was associated with higher study-end eGFR compared with routine care (B = 7.787; P< .001).

CONCLUSION

Bariatric surgery results in significant improvements in eGFR in T2D patients, particularly those with an eGFR≤60 mL/min/1.73 m², while routine care was associated with a decline in eGFR.

Clinical Outcomes of Metabolic Surgery: Microvascular and Macrovascular Complications

Understanding of the long-term clinical outcomes associated with bariatric surgery has recently been advanced. Research related to the sequelae of diabetes-in particular, long-term microvascular and macrovascular complications-in patients who undergo weight-loss surgery is imperative to this pursuit. While numerous randomized control trials have assessed glucose control with bariatric surgery compared with intensive medical therapy, bariatric surgery outcome data relating to microvascular and macrovascular complications have been limited to observational studies and nonrandomized clinical trials. As a result, whether bariatric surgery is associated with a long-term reduction in microvascular and macrovascular complications when compared with current intensive glycemic control therapy cannot be determined because the evidence is insufficient. However, the consistent salutary effects of bariatric surgery on diabetes remission and glycemic improvement support the opportunity (and need) to conduct high-quality studies of bariatric surgery versus intensive glucose control. This review provides relevant background information related to the treatment of diabetes, hyperglycemia, and long-term complications; reports clinical findings (to date) with bariatric surgery; and identifies ongoing research focusing on long-term vascular outcomes associated with bariatric surgery.

Cardiovascular and renal effects of weight reduction in obesity and the metabolic syndrome

Obesity is a critical public health issue worldwide. Patients with obesity have markedly increased morbidity and mortality compared to the general population. The increased health risks of obesity in part are due to its close association with each of the other components of the metabolic syndrome, including hypertension, dyslipidemia, and insulin resistance. Accordingly, obese individuals are at particularly increased risk of cardiovascular disease and chronic kidney disease. Modest weight loss results in improvements in serum cholesterol levels, blood pressure, and glycemic profiles. Lifestyle interventions for weight loss have long been the mainstay of treatment in obesity. However, the existing literature demonstrates limited weight loss sustainability and inconsistent cardiovascular and renal benefits using these modalities. In addition to improvements in intermediate risk factors, surgical interventions provide a more lasting impact on long-term cardiovascular and renal outcomes, though carry higher short-term risks due to perioperative complications.

Weight loss interventions and progression of diabetic kidney disease

Progressive renal impairment (diabetic kidney disease (DKD)) occurs in upwards of 40 % of patients with obesity and type 2 diabetes mellitus (T2DM) and is a cause of significant morbidity and mortality. Means of attenuating the progression of DKD focus on amelioration of risk factors. Visceral obesity is implicated as a causative agent in impaired metabolic and cardiovascular control in T2DM, and various approaches primarily targeting weight have been examined for their impact on markers of renal injury and dysfunction in DKD. The current report summarises the evidence base for the impact of surgical, lifestyle and pharmacological approaches to weight loss on renal end points in DKD. The potential for a threshold of weight loss more readily achievable by surgical intervention to be a prerequisite for renal improvement is highlighted. Comparing efficacious non-surgical weight loss strategies with surgical strategies in appropriately powered and controlled prospective studies is a priority for the field.

Disease severity and staging of obesity: a rational approach to patient selection

The increasing prevalence of obesity places ever-increasing cost demands on healthcare systems. One million individuals are eligible for bariatric surgery in the UK, and yet less than 6000 bariatric procedures are performed annually. Bariatric surgery reverses or improves almost all the medical and psychosocial co-morbidities associated with obesity. Although the BMI is a simple method to estimate adiposity at a population level, it is relatively inaccurate within an individual and provides little-to-no indication of overall health status or disease severity. Staging systems overcome the inherent limitations of BMI and allow highly informed decision-making for an individual. At a societal level, this helps to identify those most likely to gain and maximise economic benefit. This review summarises the co-morbidities associated with obesity and the evidence for their improvement following surgery. The rationale for new staging criteria and appropriate patient selection are discussed.

Impact of morbid obesity on the kidney function of patients with type 2 diabetes

AIMS

Type 2 diabetes and obesity impair kidney function. We examined their respective contributions to urinary albumin excretion (UAE) and glomerular filtration rate (GFR) in patients with type 2 diabetes and morbid obesity.

METHODS

Cross-sectional, monocentric study of kidney function in patients with type 2 diabetes classified into four body mass index (BMI) stages: non-obese (<25 kg/m(2), n=157); overweight (25 to <30, n=311); obesity (30 to <40, n=310); and morbid obesity (≥40, n=77), with 84 similarly staged controls without diabetes. UAE classes were defined as normal (<30 μg/mg creatinine), microalbuminuria (30-299), or macroalbuminuria (≥300) from 3 consecutive urine samples. GFR was measured by (51)Cr EDTA plasma disappearance (adjusted and unadjusted to 1.73 m(2) body surface area, as obesity increases body surface).

RESULTS

Participants with type 2 diabetes had same age, diabetes duration, and HbA1c across BMI stages. UAE was higher in participants with type 2 diabetes (p<0.0001), and increased with obesity stages (p<0.0001). After adjustment for age, sex, systolic blood pressure and type 2 diabetes status, morbid obesity was associated with a risk of microalbuminuria (OR 1.99, 95%CI 1.35-2.98, p=0.0007) and macroalbuminuria (OR 2.33, 95%CI 1.25-4.22, p=0.006). The body surface adjusted GFR was lower in patients with type 2 diabetes than in controls (p<0.0001), and declined with obesity stages, contrary to controls. An interaction of diabetes and obesity was seen with unadjusted GFR values (p=0.002).

CONCLUSIONS

Morbid obesity interacts with type 2 diabetes to aggravate UAE and GFR. Treatment strategies should focus on both conditions to protect kidney function in these patients.

Metabolic bariatric surgery and type 2 diabetes mellitus: an endocrinologist's perspective

Traditional treatment of T2DM consisting of modification of diet, an exercise regimen, and pharmacotherapy has problems of poor lifestyle modifications and fail tend of treatment over time, now bariatric surgery is recommended for treatment of obese patients with T2DM because its great improvements on weight loss and metabolic. In this article, effects of bariatric surgery on diabetes and diabetes-related complications are reviewed.