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

Obesity-related glomerulopathy: How it happens and future perspectives

Obesity-related glomerulopathy (ORG) is an emerging complication of excess adiposity. Its incidence rises alongside the obesity pandemic. Up to 40% of individuals can be affected by ORG, irrespective of the status of glomerular filtration rate and albuminuria. ORG is a distinct histological diagnosis based on kidney biopsy, showing classical features of an enlarged glomerulus with and without focal segmental glomerulosclerosis in the perihilar region seen with all categories of obesity. About 10% of individuals with ORG may progress to end-stage kidney disease. The invasive nature of kidney biopsy highlights the need for non-invasive biomarkers for improved screening, diagnosis and risk prediction of ORG. These biomarkers may narrow the gaps in the management of ORG by improving: (1) screening, diagnosis and differentiation of ORG from non-ORG conditions; (2) risk prediction and stratification of individuals at risk of progression to end-stage kidney disease including the detection of trajectories of progression; (3) monitoring of treatment safety and effectiveness and (4) development of novel therapeutic targets. In the present review, we discussed the pathophysiology, emerging biomarkers (such as kidney injury molecule-1 [KIM-1], uromodulin, klotho, circulating microRNA-21 [miR-21]) and future treatment strategies (metabolic surgery, sodium-glucose cotransporter-2 inhibitors, incretin-based therapy and non-steroidal mineralocorticoid antagonists) of ORG.

Metabolic/Bariatric Surgery is Safe and Effective in People with Obesity, Type 2 Diabetes Mellitus and Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Obesity, type 2 diabetes (T2D), and chronic kidney disease (CKD) are thought to increase surgical risks and reduce weight loss after metabolic/bariatric surgery (MBS). Electronic databases were searched between January 2013 and August 2023 for randomized controlled trials (RCT) of MBS reporting data on the safety, total weight loss (TWL), and metabolic control in patients with and without CKD. Forty-four out of 2904 articles were analyzed, representing 1470 patients. No significant differences were found in TWL after 1 year (- 19%, CI - 0.19 to - 0.18 vs.: - 15%, CI - 0.20 to - 0.09, p = 0.13) or after 5 years (- 20%, CI - 0.21 to - 0.18 vs. Group - 16%, CI - 0.28 to - 0.04, p = 0.50).Similarly, there were no significant differences in HbA1c at 1 year (- 1.06, CI - 1.37 to - 0.76 vs. Group 2: - 1.52, CI - 2.25 to - 0.79, p = 0.26) or after 5 years (- 0.97, CI - 1.53 to 0.41 vs. Group 2: - 1.09, CI - 2.21 to 0.03, p = 0.85). For fasting plasma glucose, no differences were seen at 2 years (- 30.43, CI - 60.47 to 0.39 vs. - 35.11, CI - 48.76 to - 21.46, p = 0.78) or after 5 years (- 11.24, CI - 53.38 to 30.89 vs. - 5.4, CI 20.22 to 9.42, p = 0.80). In terms of total cholesterol, no significant differences were found after 1 year (- 10.36, CI - 32.94 to 12.22 vs. - 19.80, CI - 39.46 to - 0.14, p = 0.54) or after 5 years (- 7.43, CI - 25.09 to 5.23 vs. - 21.30, CI - 43.08 to 0.49, p = 0.15). For triglycerides, both showed similar reductions after 1 year (- 76.21, CI - 112.84 to - 39.59 vs. - 78.00, CI - 100.47 to - 55.53, p = 0.94) and after 5 years (- 79.65, CI - 121.09 to - 38.21 vs. - 53.15, CI - 71.14 to - 35.16, p = 0.25). The presence of CKD in patients with obesity and T2D does not reduce the safety and efficacy of MBS.

Exploring Adiposity and Chronic Kidney Disease: Clinical Implications, Management Strategies, Prognostic Considerations

Obesity poses a significant and growing risk factor for chronic kidney disease (CKD), requiring comprehensive evaluation and management strategies. This review explores the intricate relationship between obesity and CKD, emphasizing the diverse phenotypes of obesity, including sarcopenic obesity and metabolically healthy versus unhealthy obesity, and their differential impact on kidney function. We discuss the epidemiological evidence linking elevated body mass index (BMI) with CKD risk while also addressing the paradoxical survival benefits observed in obese CKD patients. Various measures of obesity, such as BMI, waist circumference, and visceral fat assessment, are evaluated in the context of CKD progression and outcomes. Mechanistic insights into how obesity promotes renal dysfunction through lipid metabolism, inflammation, and altered renal hemodynamics are elucidated, underscoring the role of adipokines and the renin-angiotensin-aldosterone system. Furthermore, the review examines current strategies for assessing kidney function in obese individuals, including the strengths and limitations of filtration markers and predictive equations. The management of obesity and associated comorbidities like arterial hypertension, type 2 diabetes mellitus, and non-alcoholic fatty liver disease in CKD patients is discussed. Finally, gaps in the current literature and future research directions aimed at optimizing the management of obesity-related CKD are highlighted, emphasizing the need for personalized therapeutic approaches to mitigate the growing burden of this intertwined epidemic.

Renoprotective Effects of Metabolic Surgery Versus GLP1 Receptor Agonists on Progression of Kidney Impairment in Patients with Established Kidney Disease

OBJECTIVE

To examine the renoprotective effects of metabolic surgery in patients with established chronic kidney disease (CKD).

BACKGROUND

The impact of metabolic surgery compared with glucagon-like peptide-1 receptor agonists (GLP-1RA) in patients with established CKD has not been fully characterized.

METHODS

Patients with obesity (body mass index ≥30 kg/m 2 ), type 2 diabetes, and baseline estimated glomerular filtration rate (eGFR) 20-60 mL/min/1.73 m² who underwent metabolic bariatric surgery at a large US health system (2010-2017) were compared with nonsurgical patients who continuously received GLP-1RA. The primary end point was CKD progression, defined as a decline of eGFR by ≥50% or to <15 mL/min/1.73 m 2 , initiation of dialysis, or kidney transplant. The secondary end point was the incident kidney failure (eGFR <15 mL/min/1.73 m 2 , dialysis, or kidney transplant) or all-cause mortality.

RESULTS

425 patients, including 183 patients in the metabolic surgery group and 242 patients in the GLP-1RA group, with a median follow-up of 5.8 years (IQR, 4.4-7.6), were analyzed. The cumulative incidence of the primary end point at 8 years was 21.7% (95% CI: 12.2-30.6) in the surgical group and 45.1% (95% CI: 27.7 to 58.4) in the nonsurgical group, with an adjusted hazard ratio of 0.40 (95% CI: 0.21 to 0.76), P =0.006. The cumulative incidence of the secondary composite end point at 8 years was 24.0% (95% CI: 14.1 to 33.2) in the surgical group and 43.8% (95% CI: 28.1 to 56.1) in the nonsurgical group, with an adjusted HR of 0.56 (95% CI: 0.31 to 0.99), P =0.048.

CONCLUSIONS

Among patients with type 2 diabetes, obesity, and established CKD, metabolic surgery, compared with GLP-1RA, was significantly associated with a 60% lower risk of progression of kidney impairment and a 44% lower risk of kidney failure or death. Metabolic surgery should be considered as a therapeutic option for patients with CKD and obesity.

Long-term kidney outcomes of semaglutide in obesity and cardiovascular disease in the SELECT trial

The SELECT trial previously reported a 20% reduction in major adverse cardiovascular events with semaglutide (n = 8,803) versus placebo (n = 8,801) in patients with overweight/obesity and established cardiovascular disease, without diabetes. In the present study, we examined the effect of once-weekly semaglutide 2.4 mg on kidney outcomes in the SELECT trial. The incidence of the pre-specified main composite kidney endpoint (death from kidney disease, initiation of chronic kidney replacement therapy, onset of persistent estimated glomerular filtration rate (eGFR) < 15 ml min-1 1.73 m-2, persistent ≥50% reduction in eGFR or onset of persistent macroalbuminuria) was lower with semaglutide (1.8%) versus placebo (2.2%): hazard ratio (HR) = 0.78; 95% confidence interval (CI) 0.63, 0.96; P = 0.02. The treatment benefit at 104 weeks for eGFR was 0.75 ml min-1 1.73 m-2 (95% CI 0.43, 1.06; P < 0.001) overall and 2.19 ml min-1 1.73 m-2 (95% CI 1.00, 3.38; P < 0.001) in patients with baseline eGFR <60 ml min-1 1.73 m-2. These results suggest a benefit of semaglutide on kidney outcomes in individuals with overweight/obesity, without diabetes.ClinicalTrials.gov identifier: NCT03574597 .

Treatment of Type 2 Diabetes Mellitus in Advanced Chronic Kidney Disease for the Primary Care Physician

Diabetes mellitus (DM) is a common cause of chronic kidney disease (CKD), leading to the need for renal replacement therapy (RRT). RRT includes hemodialysis (HD), peritoneal dialysis (PD), kidney transplantation (KT), and medical management. As CKD advances, the management of DM may change as medication clearance, effectiveness, and side effects can be altered due to decreasing renal clearance. Medications like metformin that were safe to use early in CKD may build up toxic levels of metabolites in advanced CKD. Other medications, like sodium-glucose co-transporter 2 inhibitors, which work by excreting glucose in the urine, may not be able to work effectively in advanced CKD due to fewer working nephrons. Insulin breakdown may take longer, and both formulation and dosing may need to be changed to avoid hypoglycemia. While DM control contributes to CKD progression, effective DM control continues to be important even after patients have been placed on RRT. Patients on RRT are frequently taken care of by a team of providers, including the primary care physician, both in and outside the hospital. Non-nephrologists who are involved with the care of a patient treated with RRT need to be adept at managing DM in this population. This paper aims to outline the management of type 2 DM in advanced CKD.

Effects of bariatric surgery on renal function: a retrospective cohort study comparing one-year outcomes between one-anastomosis gastric bypass and Roux-en-Y gastric bypass

BACKGROUND

Evidence on the effect of one-anastomosis gastric bypass (OAGB) on renal function is limited.

OBJECTIVE

To compare the evolution of estimated renal function observed 1 year after OAGB and Roux-en-Y gastric bypass (RYGB) in individuals with obesity.

DESIGN AND SETTING

Observational, analytical, and retrospective cohort study. Tertiary-level university hospital.

METHODS

This study used a prospectively collected database of individuals who consecutively underwent bariatric surgery. Renal function was assessed by calculating the estimated glomerular filtration rate (eGFR), according to the Chronic Kidney Disease Epidemiology Collaboration. The one-year variation in the eGFR was compared between the procedures.

RESULTS

No significant differences in age, sex, obesity-associated conditions, or body mass index were observed among individuals who underwent either OAGB or RYGB. OAGB led to a significantly higher percentage of total (P = 0.007) and excess weight loss (P = 0.026). Both OAGB and RYGB led to significantly higher values of eGFR (103.9 ± 22 versus 116.1 ± 13.3; P = 0.007, and 102.4 ± 19 versus 113.2 ± 13.3; P < 0.001, respectively). The one-year variation in eGFR was 11 ± 16.2% after OAGB and 16.7 ± 26.3% after RYGB (P = 0.3). Younger age and lower baseline eGFR were independently associated with greater postoperative improvement in renal function (P < 0.001).

CONCLUSION

Compared with RYGB, OAGB led to an equivalent improvement in renal function 1 year after the procedure, along with greater weight loss.

Clinical outcomes and adverse events of bariatric surgery in adults with severe obesity in Scotland: the SCOTS observational cohort study

Background

Bariatric surgery is a common procedure worldwide for the treatment of severe obesity and associated comorbid conditions but there is a lack of evidence as to medium-term safety and effectiveness outcomes in a United Kingdom setting.

Objective

To establish the clinical outcomes and adverse events of different bariatric surgical procedures, their impact on quality of life and the effect on comorbidities.

Design

Prospective observational cohort study.

Setting

National Health Service secondary care and private practice in Scotland, United Kingdom.

Participants

Adults (age >16 years) undergoing their first bariatric surgery procedure.

Main outcome measures

Change in weight, hospital length of stay, readmission and reoperation rate, mortality, diabetes outcomes (HbA1c, medications), quality of life, anxiety, depression.

Data sources

Patient-reported outcome measures, hospital records, national electronic health records (Scottish Morbidity Record 01, Scottish Care Information Diabetes, National Records Scotland, Prescription Information System).

Results

Between December 2013 and February 2017, 548 eligible patients were approached and 445 participants were enrolled in the study. Of those, 335 had bariatric surgery and 1 withdrew from the study. Mean age was 46.0 (9.2) years, 74.7% were female and the median body mass index was 46.4 (42.4; 52.0) kg/m2. Weight was available for 128 participants at 3 years: mean change was -19.0% (±14.1) from the operation and -24.2% (±12.8) from the start of the preoperative weight-management programme. One hundred and thirty-nine (41.4%) participants were readmitted to hospital in the same or subsequent 35 months post surgery, 18 (5.4% of the operated cohort) had a reoperation or procedure considered to be related to bariatric surgery gastrointestinal complications or revisions. Fewer than five participants (<2%) died during follow-up. HbA1c was available for 93/182 and diabetes medications for 139/182 participants who had type 2 diabetes prior to surgery; HbA1c mean change was -5.72 (±16.71) (p = 0.001) mmol/mol and 65.5% required no diabetes medications (p < 0.001) at 3 years post surgery. Physical quality of life, available for 101/335 participants, improved in the 3 years post surgery, mean change in Rand 12-item Short Form Survey physical component score 8.32 (±8.95) (p < 0.001); however, there was no change in the prevalence of anxiety or depression.

Limitations

Due to low numbers of bariatric surgery procedures in Scotland, recruitment was stopped before achieving the intended 2000 participants and follow-up was reduced from 10 years to 3 years.

Conclusions

Bariatric surgery is a safe and effective treatment for obesity. Patients in Scotland, UK, appear to be older and have higher body mass than international comparators, which may be due to the small number of procedures performed.

Future work

Intervention studies are required to identify the optimal pre- and post surgery pathway to maximise safety and cost-effectiveness.

Study registration

This study is registered as ISRCTN47072588.

Funding details

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 10/42/02) and is published in full in Health Technology Assessment; Vol. 28, No. 7. See the NIHR Funding and Awards website for further award information.

Bariatric surgery in patients with obesity and end-stage renal disease

BACKGROUND

Bariatric surgery has been suggested as a treatment for obesity and end-stage renal disease (ESRD). Although the number of bariatric surgeries in patients with ESRD is increasing, its safety and effectiveness in these patients are still controversial and the surgical method of choice in these patients is under debate.

OBJECTIVES

To compare the outcomes of bariatric surgery between patients with and without ESRD and to assess different methods of bariatric surgery in patients with ESRD.

SETTING

Meta-analysis.

METHODS

A comprehensive search was conducted in Web of Science and Medline (via Pubmed) until May 2022. Tow meta-analyses were performed: A) to compare bariatric surgery outcomes among patients with and without ESRD, and B) to compare outcomes of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) in patients with ESRD. Using a random-effect model, odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs) were computed for surgical and weight loss outcomes.

RESULTS

Of 5895 articles, 6 studies were included in meta-analysis A and 8 studies in meta-analysis B. The risk of bias was moderate to serious among studies. Major postoperative complications (OR = 2.82; 95% CI = 1.66-4.77; P = .0001), reoperation (OR = 2.66; 95% CI = 1.99-3.56; P < .00001), readmission (OR = 2.37; 95% CI = 1.55-3.64; P < .0001), and in-hospital/90-d mortality (OR = 4.03; 95% CI = 1.80-9.03; P = .0007) were higher in patients with ESRD. Patients with ESRD also had a longer hospital stay (MD = 1.23; 95% CI = .32-2.14; P = .008). Bleeding, leakage, and total weight loss were comparable among groups. SG showed a 10% lower rate of overall complications and significantly shorter hospital stay than RYGB did. The quality of evidence was very low for the outcomes CONCLUSIONS: Bariatric surgery in patients with ESRD seems to have higher rates of major complications and perioperative mortality than in patients without ESRD, but a comparable rate of overall complications. SG has fewer postoperative complications and could be the method of choice in these patients. These findings should be interpreted cautiously in light of the moderate to high risk of bias in most included studies.

Glucagon-like peptide 1(GLP-1) receptor agonists in the management of the patient with type 2diabetes mellitus and chronic kidney disease: an approach for the nephrologist

Diabetic kidney disease, a common complication in patients with type 2 diabetes mellitus, is associated with a markedly increased morbidity and mortality, especially of cardiovascular origin, and faster progression to end-stage renal disease. To date, reducing cardiovascular and renal risk in this population was based on strict control of cardiovascular risk factors and the renin-angiotensin system blockade. More recently, sodium-glucose cotransporter type 2 inhibitors have demonstrated to offer cardiovascular and renal protection, but the residual risk remains high and their antihyperglycemic efficacy is limited in moderate-severe CKD. Therefore, drugs with a potent antihyperglycemic effect, independent of the glomerular filtration rate, with a low risk of hypoglycemia, that reduce weight in overweight/obese patients and that provide cardiovascular and renal protection, such as GLP-1 receptor agonists, are needed. However, these drugs require subcutaneous administration, which may limit their early use. The recent availability of oral semaglutide may facilitate the early introduction of this family with proven cardiovascular and renal benefits and excellent safety profile. In this review the family is analyzed as well as their cardiovascular and renal effects.

The Beauty and the Beast: Bariatric Surgery and a Case of Oxalate Nephropathy

Oxalate nephropathy is a rare cause of kidney failure. Roux-en-Y gastric bypass surgery is a technique used for surgical treatment of obesity as well as for the treatment of gastric carcinoma. We report the case of a 46-year-old male who was admitted to the nephrology department due to kidney dysfunction eight months after bariatric surgery.

The Effect of Chronic Kidney Disease or End-stage Kidney Disease on Perioperative Outcomes and Healthcare Utilization in Patients Undergoing Bariatric Surgery

BACKGROUND

As chronic kidney disease (CKD) has a higher prevalence in patients with obesity, there is an increasing need to understand the safety of bariatric surgery for patients with advanced CKD. This study determined if short-term bariatric surgical outcomes and healthcare utilization differ in patients with advanced CKD.

METHODS

A retrospective analysis of the Healthcare Cost and Utilization Project National Inpatient Sample (NIS) was performed. Patients with obesity who underwent bariatric surgery from 2015 to 2019 were included. Patients without CKD, with CKD, and end-stage kidney disease (ESKD) were compared for outcome differences. Univariate and multivariable regression was used to determine the association between perioperative outcomes to CKD status.

RESULTS

The unadjusted analysis found significantly higher mortality and overall complication rate in CKD and ESKD patients, however, after adjustment for confounders, only the ICU admission rate remained significantly higher for patients CKD compared to non-CKD patients (odds ratio 4.21, 95% CI [3.29-5.39]). Length of stay was longer for patients with CKD (mean difference (MD) 0.14 days, 95% CI, [0.04, 0.23]) and patients with ESKD (MD 0.27 days, 95% CI, [0.10, 0.43]) compared to non-CKD patients. Patients with ESKD had higher admission costs compared to non-CKD patients (MD $1982.65).

CONCLUSION

Patients with CKD and ESKD have increased healthcare utilization and higher rates of ICU admission after bariatric surgery compared to non-CKD patients. Otherwise, there is no significant difference in other post-operative complications and mortality. Bariatric surgery may therefore be safely offered to this patient population in hospitals with on-site ICU capacity.

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.

Interplay between metabolic dysfunction-associated fatty liver disease and chronic kidney disease: Epidemiology, pathophysiologic mechanisms, and treatment considerations

The recently proposed nomenclature change from non-alcoholic fatty liver disease to metabolic dysfunction-associated fatty liver disease (MAFLD) has resulted in the reappraisal of epidemiological trends and associations with other chronic diseases. In this context, MAFLD appears to be tightly linked to incident chronic kidney disease (CKD). This association may be attributed to multiple shared risk factors including type 2 diabetes mellitus, arterial hypertension, obesity, dyslipidemia, and insulin resistance. Moreover, similarities in their molecular pathophysiologic mechanisms can be detected, since inflammation, oxidative stress, fibrosis, and gut dysbiosis are highly prevalent in these pathologic states. At the same time, lines of evidence suggest a genetic predisposition to MAFLD due to gene polymorphisms, such as the PNPLA3 rs738409 G allele polymorphism, which may also propagate renal dysfunction. Concerning their management, available treatment considerations for obesity (bariatric surgery) and novel antidiabetic agents (glucagon-like peptide 1 receptor agonists, sodium-glucose co-transporter 2 inhibitors) appear beneficial in preclinical and clinical studies of MAFLD and CKD modeling. Moreover, alternative approaches such as melatonin supplementation, farnesoid X receptor agonists, and gut microbiota modulation may represent attractive options in the future. With a look to the future, additional adequately sized studies are required, focusing on preventing renal complications in patients with MAFLD and the appropriate management of individuals with concomitant MAFLD and CKD.

The Beneficial Effects of Bariatric-Surgery-Induced Weight Loss on Renal Function

Obesity represents an independent risk factor for the development of chronic kidney disease (CKD), leading to specific histopathological alterations, known as obesity-related glomerulopathy. Bariatric surgery is the most effective means of inducing and maintaining sustained weight loss. Furthermore, in the context of bariatric-surgery-induced weight loss, a reduction in the proinflammatory state and an improvement in the adipokine profile occur, which may also contribute to the improvement of renal function following bariatric surgery. However, the assessment of renal function in the context of obesity and following marked weight loss is difficult, since the formulas adopted to estimate glomerular function use biomarkers whose production is dependent on muscle mass (creatinine) or adipose tissue mass and inflammation (cystatin-c). Thus, following bariatric surgery, the extent to which reductions in plasma concentrations reflect the actual improvement in renal function is not clear. Despite this limitation, the available literature suggests that in patients with hyperfiltration at baseline, GFR is reduced following bariatric surgery, whereas GFR is increased in patients with decreased GFR at baseline. These findings are also confirmed in the few studies that have used measured rather than estimated GFR. Albuminuria is also decreased following bariatric surgery. Moreover, bariatric surgery seems superior in achieving the remission of albuminuria and early CKD than the best medical treatment. In this article, we discuss the pathophysiology of renal complications in obesity, review the mechanisms through which weight loss induces improvements in renal function, and provide an overview of the renal outcomes following bariatric surgery.

Renal UTX-PHGDH-serine axis regulates metabolic disorders in the kidney and liver

Global obesity epidemics impacts human health and causes obesity-related illnesses, including the obesity-related kidney and liver diseases. UTX, a histone H3K27 demethylase, plays important roles in development and differentiation. Here we show that kidney-specific knockout Utx inhibits high-fat diet induced lipid accumulation in the kidney and liver via upregulating circulating serine levels. Mechanistically, UTX recruits E3 ligase RNF114 to ubiquitinate phosphoglycerate dehydrogenase, the rate limiting enzyme for de novo serine synthesis, at Lys³¹⁰ and Lys³³⁰, which leads to its degradation, and thus suppresses renal and circulating serine levels. Consistently, phosphoglycerate dehydrogenase and serine levels are markedly downregulated in human subjects with diabetic kidney disease or obesity-related renal dysfunction. Notably, oral administration of serine ameliorates high-fat diet induced fatty liver and renal dysfunction, suggesting a potential approach against obesity related metabolic disorders. Together, our results reveal a metabolic homeostasis regulation mediated by a renal UTX-PHGDH-serine axis.

Impact of prior bariatric surgery on risk and severity of COVID-19 infection: A meta-analysis of observational studies

BACKGROUND

The association of prior bariatric surgery (BS) with infection rate and prognosis of coronavirus disease 2019 (COVID-19) remains unclear. We conducted a meta-analysis of observational studies to address this issue.

METHODS

We searched databases including MEDLINE, Embase, and CENTRAL from inception to May, 2022. The primary outcome was risk of mortality, while secondary outcomes included risk of hospital/intensive care unit (ICU) admission, mechanical ventilation, acute kidney injury (AKI), and infection rate.

RESULTS

Eleven studies involving 151,475 patients were analyzed. Meta-analysis showed lower risks of mortality [odd ratio (OR)= 0.42, 95% CI: 0.27-0.65, p < 0.001, I² = 67%; nine studies; 151,113 patients, certainty of evidence (COE):moderate], hospital admission (OR=0.56, 95% CI: 0.36-0.85, p = 0.007, I² =74.6%; seven studies; 17,810 patients; COE:low), ICU admission (OR=0.5, 95% CI: 0.37-0.67, p < 0.001, I² =0%; six studies; 17,496 patients, COE:moderate), mechanical ventilation (OR=0.52, 95% CI: 0.37-0.72, p < 0.001, I² =57.1%; seven studies; 137,992 patients, COE:moderate) in patients with prior BS (BS group) than those with obesity without surgical treatment (non-BS group). There was no difference in risk of AKI (OR=0.74, 95% CI: 0.41-1.32, p = 0.304, I² =83.6%; four studies; 129,562 patients, COE: very low) and infection rate (OR=1.05, 95% CI: 0.89-1.22, p = 0.572, I² =0%; four studies; 12,633 patients, COE:low) between the two groups. Subgroup analysis from matched cohort studies demonstrated associations of prior BS with lower risks of mortality, ICU admission, mechanical ventilation, and AKI.

CONCLUSION

Our results showed a correlation between prior BS and less severe COVID-19, which warrants further investigations to verify.