Although higher BMI may confer survival benefit to dialysis patients, obesity is often an obstacle to renal transplantation. A new study by Segev et al (J Am Soc Nephrol. 2008;19:349-355) looks at the association between BMI and waiting time for a kidney transplant, examining 132,353 candidates listed with the United Network for Organ Sharing (UNOS) from 1995 to 2006.
Based on their findings, the authors noted that “likelihood of receiving a transplant decreased and likelihood of being bypassed increased significantly for higher BMI categories, even after adjustment for all factors relevant to the allocation system, factors possibly influencing access to health care, and factors that could influence provider risk-benefit decisions.”
Whether higher BMI should contraindicate renal transplantation is a matter of debate because a previous study by Glanton et al (Kidney Int. 2003;63:647-653) of 7,521 dialysis patients with a BMI above 30 kg/m2 enrolled on the renal transplant waiting list from 1995 to 2000 found a lower risk of mortality in obese transplanted compared with those remaining on the list (though this benefit did not accrue to those with a BMI above 41 kg/m2).
So, when should weight control be addressed? Current information indicates potential benefit for patients in early stages of CKD and for those desiring renal transplantation. Weight control is difficult at best for the average individual, and particularly challenging in CKD. Adequate calorie intake to minimize muscle catabolism and prevent malnutrition is important, especially in stages 3 and 4 CKD when protein intake may be restricted.
For stage 5 CKD patients the additional dietary and fluid limitations required by hemodialysis or the extra calories from peritoneal dialysate complicate efforts to lose weight. The American Dietetic Association’s “Adult Weight Management Evidence-Based Nutrition Practice Guideline” (www.adaevidencelibrary.com) provides information that may assist in advising CKD patients.
Strategies associated with successful weight control outcomes include:
- Physical Activity: “…at least 30 minutes or more of moderate intensity physical activity on most, and preferably, all days of the week, unless medically contraindicated. Physical activity contributes to weight loss, may decrease abdominal fat, and may help with maintenance of weight loss.”
- Comprehensive Weight Management Program: “Weight loss and weight maintenance therapy should be based on a comprehensive weight management program including diet, physical activity, and behavior therapy. The combination therapy is more successful than using any one intervention alone.”
- Realistic Weight Goals: “…to reduce body weight at an optimal rate of 1-2 lbs per week for the first 6 months and to achieve an initial weight loss goal of up to 10% from baseline. These goals are realistic, achievable, and sustainable.”
- Multiple Behavior Therapy Strategies: “A comprehensive weight management program should make maximum use of multiple strategies for behavior therapy (e.g., self monitoring, stress management, stimulus control, problem solving, contingency management, cognitive restructuring, and social support).”