Background: The increased prevalence of obesity (BMI > 30) among adults in the United States over the last two decades is reflected in the number of moderately (BMI 35-39) and morbidly (BMI > 40) obese patients awaiting kidney transplant (KTx). It is often debated whether the possible benefits are sufficient enough to advocate transplant over dialysis in this population. This systematic review examines the outcomes of moderately and morbidly obese KTx recipients.

Methods: Medline, PubMed, Ovid, Google scholar and CINAHL were systematically searched using the key words "obesity" "kidney transplant" "adults" and "bariatric surgery". Studies were included if they provided quantitative data pertinent to medical or surgical outcomes of KTx recipients with BMI > 35. Outcome measures included: graft survival, patient survival and glomerular filtration rate (GFR) at 1, 3 and 5 years, delayed graft function, biopsy proven rejection, lymphocele, wound infection and hematoma. An English language restriction was applied. Case reports, letters, editorials and reports in abstract form or conference proceedings were excluded. A total of 266 papers were screened for relevance, 18 met inclusion criteria and were incorporated in the review.

Results: Findings support an increased rate of wound complications and the need for rigorous assessment of comorbid cardiovascular conditions prior to transplant, but were inconclusive regarding the benefit of pre-transplant weight loss. Some report lower rates of patient and graft survival when compared to those with BMI <35. Importantly, there is evidence that KTx provides a significant survival benefit when compared to patients with BMI > 35 that were maintained on dialysis, and supports KTx in some morbidly obese patients with BMI ≥ 40. Health Related Quality of Life (HRQOL) was assessed in 1 study and was not significantly affected by BMI (range: 35-39).

Conclusion: Findings did not support arbitrary restrictions on KTx for moderately and morbidly obese patients and identified significant gaps in the current literature that must be addressed in future studies. Assessments of HRQOL in KTx recipients with BMI > 35 may help to clarify uncertainty regarding KTx by providing supportive evidence for clinical decision-making, resource allocation and healthcare policy in this population.

CITATION INFORMATION: Walczak D, Benedetti E. The Impact of Body Mass Index > 35 on Kidney Transplant Outcomes: A Systematic Review. Am J Transplant. 2016;16 (suppl 3).

« Back to 2016 American Transplant Congress