Background:
Whether overweight or obese end stage renal disease (ESRD) patients are eligible for renal transplantation is often debated. No (systematic) reviews have yet been carried out regarding this subject. The aim of this review and meta-analysis is to systematically investigate outcome of low- versus high Body Mass Index (BMI) recipients after renal transplantation.

Material and Methods:
Comprehensive searches were conducted in several databases. Meta-analysis was performed with Review Manager 5.2. The methodology was in accordance with the Cochrane Handbook for Interventional Systematic Reviews, and written based on the PRISMA-statement.

Result:
Forty-two studies were selected and reviewed. Thirty-seven outcome measures were reviewed and twenty-six could be meta-analysed. Of these, the following demonstrated significant differences of risk ratios in favour of low BMI (<30) recipients: death, delayed graft function, wound infection, NODAT, length of stay, hypertension, graft survival at 1 and 3 years and patient survival at 1 and 3 years, all p < 0.01. Furthermore, acute rejection (p = 0.03) and incisional hernia (p = 0.04).

Conclusion:
This study is the first that combines a large number of articles and outcome measures in overweight and obese renal transplant recipients. Several of these show significant benefit for low BMI (<30) recipients. Therefore, we conclude that ESRD patients with a BMI >30 preferably should lose weight prior to RT. If this cannot be achieved with common measures, in morbidly obese (BMI ≥ 40) RT candidates, bariatric surgery could be considered.