Renal Function in Type 2 Diabetes Following Gastric Bypass

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.

[Metabolic surgery]

In recent years the surgical treatment of metabolic diseases has become established as an effective alternative to conservative treatment. The new S3 guidelines address these changes and give clear indications for obesity surgery. One of the core points of the new guidelines is the differentiation between obesity surgery and metabolic surgery. In obesity surgery the primary aim of treatment is weight loss whereas for metabolic indications the aim is an improvement of comorbidities independent of the body mass index (BMI). With respect to the selection of procedures sleeve gastrectomy (SG) and the traditional Roux-en-Y gastric bypass (RYGB) can be used as safe and evidence-based operative procedures. The RYGB has better metabolic effects but higher complication and reintervention rates. More recent procedures, such as the one anastomosis gastric bypass (OAGB) and single anastomosis duodeno-ileal (SADI) bypass possibly have slightly stronger metabolic effects, however, the risk of malnutrition and vitamin deficiency is higher.

Comorbidities as an Indication for Metabolic Surgery

Metabolic diseases, comprising type 2 diabetes mellitus (T2DM), dyslipidemia, and non-alcoholic steatohepatitis (NASH), are rapidly increasing worldwide. Conservative medical therapy, including the newly available drugs, has only limited effects and does neither influence survival or the development of micro- or macrovascular complications, nor the progression of NASH to liver cirrhosis, nor the development of hepatocellular carcinomas in the NASH liver. In contrast, metabolic surgery is very effective independent of the preoperative body mass index (BMI) in reducing overall and cardiovascular mortality in patients with T2DM. Furthermore, metabolic surgery significantly reduces the development of micro- and macrovascular complications while being the most effective therapy in order to achieve remission of T2DM and to reach the targeted glycemic control. Importantly, even existing diabetic complications such as nephropathy as well as the features of NASH can be reversed by metabolic surgery. Here, we propose indications for metabolic surgery due to T2DM and NASH based on a simple but objective, disease-specific staging system. We outline the use of the Edmonton Obesity Staging System (EOSS) as a clinical staging system independent of the BMI that will identify patients who will benefit the most from metabolic surgery.

[Bariatric surgery: Expectations and therapeutic goals-a contradiction?]

In the majority of patients with morbid obesity, metabolic/bariatric surgery leads to relevant and sustained weight loss and improves obesity-related comorbidities, quality of life and functionality. Moreover, the associated reduction of risk factors for cardiovascular events and cancerous diseases has been shown to improve life expectations. Due to its excellent antidiabetic effect, the currently valid national S3 guidelines now recommend metabolic/bariatric surgery in patients who have a body mass index (BMI) ≥30 kg/m² with poorly controlled diabetes. The Edmonton staging system enables a multidimensional consideration of the severity grade of obesity for each individual patient independent of the BMI. Patients with relevant obesity-related metabolic comorbidities should be prioritized for treatment and if possible before the occurrence of end-organ damage that is at least in some cases irreversible and which also increases the perioperative risk. Therapeutic goals for each individual patient should be carefully defined preoperatively in order to mediate realistic expectations. Unrealistic expectations, such as "surgery solves my problems", "surgery makes me more beautiful", "surgery eliminates stigma", and "surgery guarantees success", are common in bariatric surgery patients. These unrealistic expectations can lead to frustration and to severe psychological decompensation and need to be addressed as early as possible by an interdisciplinary team. Redundancies, conclusive and empathic communication in the team improve therapy adherence, the expectations and therefore the overall outcome.

Dissecting the Physiology and Pathophysiology of Glucagon-Like Peptide-1

An aging world population exposed to a sedentary life style is currently plagued by chronic metabolic diseases, such as type-2 diabetes, that are spreading worldwide at an unprecedented rate. One of the most promising pharmacological approaches for the management of type 2 diabetes takes advantage of the peptide hormone glucagon-like peptide-1 (GLP-1) under the form of protease resistant mimetics, and DPP-IV inhibitors. Despite the improved quality of life, long-term treatments with these new classes of drugs are riddled with serious and life-threatening side-effects, with no overall cure of the disease. New evidence is shedding more light over the complex physiology of GLP-1 in health and metabolic diseases. Herein, we discuss the most recent advancements in the biology of gut receptors known to induce the secretion of GLP-1, to bridge the multiple gaps into our understanding of its physiology and pathology.

Patient Perspective in Obesity Surgery: Goals for Weight Loss and Improvement of Body Shape in a Prospective Cohort Study

OBJECTIVE

Obesity surgery provides sustainable weight loss, improvement of comorbidities, and improved quality of life (QOL). There is few evidence on the patient perspective and goals. This study compared expected and achieved weight loss, body shape, and QOL.

METHODS

Patients completed the Moorehead-Ardelt QOL questionnaire (MAQOL) and questionnaires on actual and expected weight loss and body shape, comorbidities, and goals of obesity surgery preoperatively and within 24 months postoperatively.

RESULTS

44 patients completed questionnaires pre- and postoperatively. BMI, MAQOL and comorbidities significantly improved postoperatively. Patients' expected weight loss goal corresponded to a postoperative BMI of 32.6 ± 5.6 kg/m2 and was not different from their achieved BMI within 24 months after surgery (33.9 ± 6.3 kg/m2, p = 0.276). Self-reported body shape improved but did not reach preoperatively expected goals. During the weight loss period, patients adapted their weight loss and body shape goals to higher levels. Patients attributed a higher part of their success in weight loss to surgery postoperatively (79.5 ± 22.0 vs. 89.1 ± 18.4%, p = 0.028).

CONCLUSION

Patients lost as much weight as they had expected and later modified the goals to even greater weight loss. Body shape improved but did not reach expected levels. QOL improved independently from weight loss and body shape. Patients attributed successful weight loss predominantly to surgery.