Albuminuria in Patients with Morbid Obesity and the Effect of Weight Loss Following Bariatric Surgery

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.

The Impact of Bariatric Surgery on Incident Microvascular Complications in Patients With Type 2 Diabetes: A Matched Controlled Population-Based Retrospective Cohort Study

OBJECTIVE

To assess the impact of bariatric surgery (BS) on incident microvascular complications of diabetes-related foot disease (DFD), sight-threatening diabetic retinopathy (STDR), and chronic kidney disease (CKD) in patients with type 2 diabetes and obesity.

RESEARCH DESIGN AND METHODS

A retrospective matched, controlled population-based cohort study was conducted of adults with type 2 diabetes between 1 January 1990 and 31 January 2018 using IQVIA Medical Research Data (IMRD), a database of primary care electronic records. Each patient with type 2 diabetes who subsequently had BS (surgical group) was matched on the index date with up to two patients with type 2 diabetes who did not have BS (nonsurgical group) within the same general practice by age, sex, preindex BMI, and diabetes duration.

RESULTS

Included were 1,126 surgical and 2,219 nonsurgical participants. In the study population 2,261 (68%) were women. Mean (SD) age was 49.87 (9.3) years vs. 50.12 (9.3) years and BMI was 46.76 (7.96) kg/m² vs. 46.14 (7.49) kg/m² in the surgical versus nonsurgical group, respectively. In the surgical group, 22.1%, 22.7%, 52.2%, and 1.1% of patients had gastric band, sleeve gastrectomy, Roux-en-Y gastric bypass (RYGB), and duodenal switch, respectively. Over a median follow-up of 3.9 years (interquartile range 1.8-6.4), BS was associated with reduction in incident combined microvascular complications (adjusted hazard ratio 0.53, 95% CI 0.43-0.66, P < 0.001), DFD (0.61, 0.50-0.75, P < 0.001), STDR (0.66, 0.44-1.00, P = 0.048), and CKD (0.63, 0.51-0.78, P < 0.001). Analysis based on the type of surgery showed that all types of surgery were associated with a favorable impact on the incidence of composite microvascular complications, with the greatest reduction for RYGB.

CONCLUSIONS

BS was associated with a significant reduction in incident diabetes-related microvascular complications.

Effect of Conventional Medical Therapy or Laparoscopic Sleeve Gastrectomy on Urinary Albumin in Japanese Subjects with Severe Obesity: An Observational Study

INTRODUCTION

In patients with severe obesity, albuminuria can be improved by both conventional medical therapy and bariatric surgery. The purpose of this study was to compare the impact of weight loss achieved through conventional medical therapy or laparoscopic sleeve gastrectomy (LSG) on albuminuria in Japanese subjects with severe obesity and identify the factors involved.

METHODS

We retrospectively evaluated the clinical characteristics including the urinary albumin/creatinine ratio (UACR) of 340 consecutive subjects with a body mass index ≥35 who received LSG (n = 242) or medical therapy (n = 98) between 2010 and 2018 and were followed for at least 12 months.

RESULTS

The baseline of the UACR was not different between the 2 groups. At the 12-month follow-up, total weight loss (TWL) and decreases in glycosylated hemoglobin (HbA1c) and loge UACR were greater in the LSG group than in the medical therapy group (body weight; -35.7 kg vs. -8.0 kg, p < 0.001, HbA1c; -1.4% vs. -0.7%, p < 0.001, loge UACR; -0.3 vs. 0.9, p < 0.001). The rate of complete remission of diabetes was significantly higher in the LSG group than in the medical therapy group. At 12 and 36 months (n = 111 in the medical therapy group, n = 56 in the LSG group at 36 months), loge UACR increased in the medical therapy group, while it remained unchanged or decreased in the LSG group. In subjects with microalbuminuria and macroalbuminuria, changes in the loge UACR correlated with percent total body weight loss (%TWL) in both groups at 12 months. Percent TWL contributed independently to the change in the loge UACR, irrespective of whether LSG was performed. In receiver-operating characteristic analysis, a weight loss of 7.8% predicted a decrease in the UACR (∆UACR <0 at 12 months).

CONCLUSION

Our analysis suggests that albuminuria may increase over time if only medical therapy is continued. To improve albuminuria, weight loss may be more important than whether LSG is performed.

Renal changes and estimation of glomerular filtration rate using different equations in morbidly obese Egyptian patients

BACKGROUND AND AIMS

Obesity is a worldwide pandemic with multiple consequences including kidney affection. This study aimed to assess the effects of obesity on renal functions and to detect the most reliable formula of estimated glomerular filtration rate (eGFR) in morbidly obese patients.

METHODS

A cross-sectional, observational study was conducted on 82 morbidly obese patients. Anthropometric measurements were done for all patients and body adiposity (BAI) and visceral adiposity (VAI) indices were calculated after assessment of abdominal fat tissue analysis by computerized tomography (CT). Serum creatinine was incorporated into six different formulae of eGFR, then eGFR was compared with the 24-h measured creatinine clearance (CL_cr) values.

RESULTS

The mean body mass index was 55.8 ± 9.5 kg/m². Proteinuria and glomerular hyperfiltration (CL_cr > 130 ml/min/1.73 m²) were detected in 68.3% and 91.5% of the patients, respectively. Cockcroft-Gault formula using total (CCG-TBW-eGFR) and adjusted body water (CCG-AjBW-eGFR) had the nearest values to measured CL_Cr. These two formulae had a moderate reliability and the lowest percentage of error (30% and 23%, respectively). Visceral and total abdominal fat tissue surface area and volume assessed by CT were directly correlated to the 24-h urinary protein excretion (r = 0.32, 0.24, 0.37 and 0.34, respectively; p = 0.02, 0.03, 0.004 and 0.002, respectively).

CONCLUSIONS

Glomerular hyperfiltration and proteinuria are highly prevalent in morbidly obese patients. There is no ideal formula for GFR estimation in morbidly obese patients, however, TBW and AjBW incorporated into the Cockcroft-Gault can be helpful in those patients.