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Meta-Analysis
. 2016 Oct 4;11(10):e0163907.
doi: 10.1371/journal.pone.0163907. eCollection 2016.

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

Kun Li  1 , Jianan Zou  2 , Zhibin Ye  2 , Jianzhong Di  3 , Xiaodong Han  3 , Hongwei Zhang  3 , Weijie Liu  3 , Qinggui Ren  3 , Pin Zhang  3
Affiliations
Meta-Analysis

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

Kun Li et al. PLoS One. .

Abstract

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.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Flow diagram of the selection process.
RCT: randomized, controlled trial.
Fig 2
Fig 2. Forest plot comparing glomerular hyperfiltration (dichotomous data) between presurgery and postsurgery.
unadj/BSA: unadjusted for BSA; adj/BSA: adjusted for BSA.
Fig 3
Fig 3. Forest plot comparing glomerular hyperfiltration (continuous data) between presurgery and postsurgery.
mGFR: measured glomerular filtration rate; eGFR: estimated glomerular filtration rate; Crcl: creatinine clearance; BSA: body surface area; unadj/BSA: unadjusted for BSA; adj/BSA: adjusted for BSA.
Fig 4
Fig 4. Forest plot comparing CKD II (continuous data) between presurgery and postsurgery.
eGFR: estimated glomerular filtration rate; BSA: body surface area.
Fig 5
Fig 5. Forest plot comparing albuminuria and proteinuria (dichotomous data) between presurgery and postsurgery.
Fig 6
Fig 6. Forest plot comparing albuminuria and proteinuria (continuous data) between presurgery and postsurgery.
DN3: Diabetic Nephropathy stages III; DN4: Diabetic Nephropathy stages IV; ACR: albumin-to-creatinine ratio.
Fig 7
Fig 7. The sensitivity analysis of the results of the meta-analysis of the effect of bariatric surgery on glomerular hyperfiltration.
Fig 8
Fig 8. The sensitivity analysis of the results of the meta-analysis of the effect of bariatric surgery on albuminuria and proteinuria.
See this image and copyright information in PMC

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