Nephrologists can address inertia behind obesity care
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Obesity is an important health issue for patients with chronic kidney disease, speeding its progression, contributing to disability and limiting access to organ transplantation. Up to now, nephrologists typically do not manage obesity.
“There’s a huge amount of inertia with obesity management,” Holly J. Kramer, MD, MPH, professor in the division of nephrology and hypertension at Loyola University Chicago Stritch School of Medicine, told Healio | Nephrology News & Issues. “We’re so used to just living with it. We have all these other things to talk about, and so we’re just accustomed to not talking about it and not doing anything about it.”
With medications that can confer substantial weight loss now available — and consumers interested in using these — nephrologists have an opportunity to address the burden of obesity for patients with CKD. The American Society of Nephrology selected obesity management as the first topic in its new series of kidney health guidance documents.
“That [choice] was influenced by what we’re seeing in terms of newer therapies and emerging evidence about the role that obesity plays in so many different aspects of kidney care, as well as the numerous opportunities that we have to better support people as they try to achieve a healthy weight,” Deidra C. Crews, MD, ScM, FASN, professor of medicine at Johns Hopkins University School of Medicine and ASN president, told Healio | Nephrology News & Issues.
Obesity matters in kidney disease
The relationship between obesity and kidney disease “is a continuing area of study,” Crews said. “It is thought that obesity has both direct and some indirect effects, not just on the development of kidney diseases, but also their progression.”
Obesity and kidney diseases are “correlating pathologies,” according to Aleksandra Kukla, MD, associate professor of medicine in the division of nephrology and hypertension at Mayo Clinic in Rochester, Minnesota. Conditions often associated with obesity, such as hypertension and type 2 diabetes, influence CKD progression. But even without those comorbidities, increased BMI and central adiposity contribute to kidney dysfunction associated with so-called obesity-related nephropathy and fatty kidney disease, Kukla said. Inflammation can promote both obesity and kidney disease.
Similarly, kidney disease can contribute to obesity through dietary restrictions that affect healthy food choices and anemia and fatigue that affect exercise ability. Some kidney medications, such as corticosteroids, promote weight gain.
“It can be a lot harder for [patients with kidney disease] to lose weight than the general population, although in the general population it is pretty hard,” Kukla said.
Perhaps the greatest effect of obesity on CKD is to limit treatment options. Obesity may make the initial surgeries for peritoneal dialysis difficult, and patients with severe obesity typically are not eligible for kidney transplant, Crews said.
“And so again, obesity can play a role in our management choices for people with kidney diseases, as well as it can be a driver of the development of kidney disease in the first place,” she said.
Lifestyle, medication, surgery
For patients with CKD, weight loss can be most important for potential kidney transplant recipients who have obesity. Outcomes are worse for recipients with obesity, especially those who already have metabolic complications, such as diabetes. Each transplant center sets its own BMI cutoff for transplant eligibility; at Mayo Clinic, the cutoff is 40 kg/m2, Kukla said.
“When I meet with potential kidney transplant recipients, I discuss with them that even if the BMI cutoff is quite generous, if they want to have the best outcomes, they should be healthy first,” Kukla said. “That’s what obesity treatment, including bariatric surgery, can help them with. It is not only for weight loss, but specifically bariatric surgery can improve their diabetes, mobility so they recover from the surgery better, obstructive sleep apnea and hypertension, both also associated with CVD, improves — there are a lot of good things of focusing on weight loss prior to a kidney transplant.”
Although essential, lifestyle modification alone — diet, exercise, stress management — is rarely effective for rapid and long-term weight loss maintenance. The glucagon-like peptide-1 receptor agonist semaglutide and other newer incretin agents, although greatly effective for weight loss, have not been extensively studied in patients with CKD beyond recent positive findings of the FLOW study (see First Word column here).
Kukla recommends bariatric surgery for patients with severe obesity seeking a kidney transplant. The strategy has been shown to prepare patients for transplant faster than other weight loss modalities.
In a study Kukla conducted with colleagues, transplant candidates with obesity (mean BMI at baseline 41 kg/m2) who underwent sleeve gastrectomy vs. non-surgical obesity care were nearly four times more likely to be placed on a waitlist for a kidney within a mean 15.5 months of follow-up and more than three times more likely to receive a kidney transplant within a median of 20.9 months.
Medical therapy can augment weight loss for patients who have had bariatric surgery and have not met their weight loss goal, Kukla said. Obesity, like hypertension, is a relapsing disease and medication might become a good option for maintenance.
“Having medical therapy, as well as surgery, is exciting,” she said.
Role of nephrologists in obesity care
Nephrologists “don’t have to ignore obesity. You can actually do something about it,” Kramer said.
When talking with patients about obesity, Kramer recommends first asking whether the patient is open to the conversation and then, if so, discussing weight loss in the context of desired outcomes.
Crews agreed and said clinicians must mindfully manage conversations about weight.
“Words matter when counseling patients about trying to achieve a healthy weight,” Crews said. “The health care setting ... can be one where [people with obesity] may feel stigmatized. ... Physicians tend to not always use the most appropriate language that is sensitive and respectful to people when they’re discussing and helping them achieve their weight goals.”
Nephrologists should consider social factors that might limit access to healthy foods and places for recreation and exercise. Coexisting mood disorders, anxiety and depressive symptoms can make weight management difficult.
“All of these things come into play, and it becomes critical that clinicians consider them as a part of that treatment plan for helping patients to achieve a healthy weight,” Crews said.
An interdisciplinary team is most often required for successful weight management.
With that in mind, Kramer said, she has been “a nudger,” contacting primary care providers and encouraging behavioral changes with referrals to dietitians, mental health providers, social workers, physical therapists and obesity specialists.
In addition, nephrologists can suggest patients consider obesity medications and bariatric surgery.
Clinical, policy questions
Obesity management for patients with CKD could be greatly improved with health policy changes surrounding education and access, Kramer said.
“Everyone with kidney disease should be seen by a registered dietitian — that’s my soapbox — and only 10% of patients are talking to a registered dietitian,” she said.
In addition, Kramer would like to see nurse education for CKD reimbursed as it is for diabetes education, and physical therapy or exercise rehabilitation reimbursed for kidney failure as it is for CVD.
“That’s a huge gap in care,” Kramer said.
Clinical questions also remain.
The global nonprofit Kidney Disease: Improving Global Outcomes held its recent controversies conference on the relationship between obesity and CKD in October 2024.
“There were a lot of controversies about obesity treatment and how the different BMI thresholds for organ donors and recipients may differ across countries,” Kukla said. “It just underscores how little work on the basics we have done.”
Important questions still to explore include when to start addressing weight for patients with CKD and when to introduce obesity medications or recommend surgery.
“We have more and more studies showing that maybe people who have so-called metabolically healthy obesity are going to see problems in the future,” Kukla said. “We need more studies to identify people at risk for obesity-related kidney disease to implement the most effective prevention.”
- References:
- Ikizler TA, et al. J Am Soc Nephrol. 2024;doi:10.1681/ASN.0000000512.
- Kulka A, et al. Mayo Clin Proc. 2023;doi.org/10.1016/j.mayocp.2024.01.017.
- For more information:
- Deidra C. Crews, MD, ScM, FASN, can be reached at dcrews1@jhmi.edu.
- Holly J. Kramer, MD, MPH, can be reached at hkramer@lumc.edu.
- Aleksandra Kukla, MD, can be reached at kukla.aleksandra@mayo.edu.
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