Obesity isn't often considered with transplants
It's associated with worse outcomes
Obesity presents many ethical challenges for transplant practice, according to a review article that describes an approach for applying available data on the importance of body composition to the kidney transplant population.1
"Our article demonstrates that in most studies, markers of obesity are associated with worse post-transplant outcomes delayed graft function, graft failure, cardiac disease, and high costs compared with ideal body composition," says Krista L. Lentine, MD, MS, associate professor of medicine at Saint Louis (MO) University Center for Outcomes Research. However, current data have not identified limits of body composition that preclude clinical benefit from kidney transplant compared to continued waiting on dialysis, or proven that weight-loss interventions improve outcomes.
Data on outcomes differences in obese patients can be used to support body mass index (BMI) thresholds as one of the criteria for transplant listing, says Lentine. "The demand for donated kidneys outpaces supply, and choices are necessary," she adds. "Currently, BMI is not part of the criteria for organ allocation after listing, but candidacy criteria [utilized by centers] determine who gets to be on the waiting list for a transplant."
In determining transplant candidacy, the ongoing ethical challenge is to balance optimization of organ utility by considering outcomes in obese compared to normal weight patients, against the justice of offering organs to all patients who may benefit from a transplant compared with their own experience on dialysis, as well as physician autonomy in making clinical decisions for individual patients, says Lentine.
Lentine emphasizes that the decision to transplant an obese patient is not solely an ethical or cost-effectiveness decision, but is first and foremost a medical/surgical decision. "Clinical judgment is needed to weigh factors that are not reflected in BMI, such as the surgeon's assessment of the safety and feasibility of a transplant operation based on the distribution of abdominal fat in a particular patient," she says.
Since obesity is a potentially modifiable risk factor, shared responsibility agreements for patients to lose some weight before transplant listing seem appropriate in many cases, argues Lentine. "Just as patients with alcoholic liver disease are required to stop drinking prior to transplant, it may be reasonable to ask kidney transplant candidates to lose excess body fat and attempt to increase lean muscle mass by becoming more physically active and modifying their diet," she suggests.
However, the lack of prospective data on the impact of intentional weight loss complicates efforts to manage obesity among end-stage renal disease patients, says Lentine. Transplant centers, primary nephrologists, and patients often face limited resources to access and pay for modalities such as monitored dietary changes, exercise programs, and bariatric surgery.
"For these reasons, bioethical input on the appropriate balance of utility, justice, autonomy, and management considerations related to obesity among potential transplant candidates is vital," Lentine says, adding that bioethicists can help resolve current controversies by entering public discussions on these areas:
- The need for more public funding of prospective studies of the impact of intentional weight-loss efforts among obese end-stage renal disease patients, including dietary changes, monitored exercise programs, and bariatric surgery.
- The need to determine to what extent chronically ill, obese patients are responsible to attempt to optimize their own body composition prior to receiving a donated organ.
- The need for formal clinical and cost-effectiveness studies, including appropriate quality-of-life adjustments that capture impact of complications, to determine if payers and society should be compensating centers for clinical and financial risks of transplanting obese end-stage renal disease patients.
"Evidence-based reimbursement decisions, such as a modified [diagnosis-related group] payment to cover higher risk transplants if determined to be cost-effective, would certainly impact transplant practice," Lentine says.
Societal or individual level?
A key ethical issue is deciding whether responses to obesity should focus on the societal or individual level, or both, according to Harald Schmidt, PhD, a lecturer in the Department of Medical Ethics andHealth Policy at University of Pennsylvania's Perelman School of Medicine in Philadelphia.
"Action on the societal level includes interventions such as regulating fat and sugar levels in foods and drinks. Here, the key opposition comes from industry and politics," he says. Other less controversial options at the societal level include providing affordable opportunities for exercise, such as free or subsidized gym memberships.
"Interventions that focus on the individual level are also becoming increasingly common, especially in the employment context," he notes. For example, some employers impose considerably higher insurance premiums on overweight and obese employees.
Such policies pose risks of "victim-blaming," in which people are held responsible for factors that are beyond their control. "At the same time, we need to recognize that individual behavior does play a key role in obesity prevention," says Schmidt. "We need action at both the social and individual level, but we must take care not to penalize people unduly." Employers who cover employees' health insurance are increasingly interested in having employees with normal BMIs, for instance, and new rules on wellness incentives will enable employers to penalize employees up to $1,500 per year if they don't meet health standards.
"But employers may also offer rewards up to this amount," says Schmidt. "Depending on how exactly incentives are implemented, they can promote or undermine autonomy." It makes no sense to set out responsibilities that people are unable to comply with or that are extremely challenging to achieve, he argues, and incentive programs need support structures to help people achieve health goals.
"At the societal level, politicians and policy makers must realize that not acting on evidence-based policies, or not trying out new policies and evaluating their effect, can have real cost in terms of lost human welfare," says Schmidt. "Doing nothing is not a neutral position. Given current levels of obesity, not intervening requires justification, too."
1. Lentine KL, Santos RD, Axelrod D, et al. Obesity and kidney transplant candidates: How big is too big for transplantation? Am J Nephrol 2012;36:575-586.
- Krista L. Lentine, MD, MS, Associate Professor of Medicine, Saint Louis (MO) University Center for Outcomes Research. Email: email@example.com.
- Harald Schmidt, PhD, Lecturer, Department of Medical Ethics and Health Policy/Research Associate, Center for Health Incentives and Behavioral Economics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Phone: (215) 573-4519. Email: firstname.lastname@example.org.