Recipients of kidney transplant have markedly improved outcomes compared with patients on dialysis; however, survival among kidney transplant recipients is significantly reduced compared with age-matched general population. The reduction in survival is due, in large part, to an increase in the risk of cardiovascular disease. Weight gain, obesity, and diabetes are risk factors for cardiovascular disease, and there is an association between obesity and increased risk of graft loss and death.
Kidney transplant recipients commonly experience weight gain, particularly in the first year following the procedure; increases of >10% of baseline weight are common. Weight gain after transplant is a modifiable risk factor for poor outcomes and is an appropriate target for therapeutic interventions. There are few data available on the use of interventions to address nutrition, behavior, and physical activity to promote weight loss among kidney transplant recipients; results of studies on nutrition interventions after transplant are inconclusive.
Cordula K. Henggeler, MHSc, and colleagues conducted the INTENT (Intensive Nutrition Interventions on Weight Gain after Kidney Transplantation) trial, a single-blind, randomized controlled trial, to examine whether an early, intensive nutrition intervention could reduce weight gain and improve body composition, physical activity, and other measures, compared with standard care in the first year after kidney transplantation. Results of the trial were reported in the Journal of Renal Nutrition [2018;28(5):340-351].
Adult kidney transplant recipients in Auckland, New Zealand, were recruited for trial participation in the first month following transplant. Inclusion criteria were stable graft function, typically defined as a serum creatinine within 20% of baseline, and agreement to participate for the duration of the trial (12 months). Exclusion criteria were body mass index (BMI) >40 kg/m2 or <18.5 kg/m2, significant malnutrition, defined as requiring enteral/parenteral nutrition therapy, or ongoing significant medical complications, determined by a physician.
All participants received care at the regional transplant center for the first 2 months after transplantation; from month 3 onward, they received routine transplant care at the local hospital renal unit. Study visits were conducted at the transplant center.
Participants were randomized in a 1:1 ratio to the intensive nutrition intervention (intervention group) or to standard care (control group). The primary outcome of interest was body weight at 6 months after transplant, adjusted for baseline weight, obesity (BMI ≥30 kg/m2), and gender. Secondary outcomes were changes in weight and other anthropometric measures, body composition, resting energy expenditure, measures of physical function, physical activity, serum biochemistry, and quality of life at 3, 6, and 12 months following transplantation.
In addition to standard care, participants in the intervention group received eight additional consultations with a renal dietitian (a total of 12 visits over 12 months). Between months 1 and 3, consultations were offered every two weeks; between months 3 and 6, consultations were offered monthly; and between months 7 and 12, consultations were offered every two months. Participants in the intervention group also received tailored physical activity and exercise advice at 2, 3, and 6 months post-transplant.
A total of 111 kidney transplants were performed between March 2014 and July 2015; of those, 60 patients met eligibility criteria. The study population included 37 participants: 19 were randomized to the intervention group and 18 to the control group. One participant in the intervention group withdrew prior to the baseline assessment and was excluded. Five participants in each group withdrew during follow-up. A total of 36 participants completed the study and were included in the final analysis of the primary outcome.
For the primary outcome, there was no significant difference in weight at 6 months: 77.0 kg in the intervention group versus 82.2 kg in the control group. Similar results were found in a per-protocol analysis of the 26 participants who completed the study. There were no between-group differences seen in secondary outcomes. Across the total cohort, total body protein and physical function improved. Adverse changes were seen for total body fat, hemoglobin A1c, and fasting glucose across the cohort.
Limitations to the study cited by the authors included the relatively small sample size, not being able to prevent trial participants to interact with each other, and the nutrition care provided to the participants may not be available at all centers.
In conclusion, the researchers said, “The INTENT trial did not demonstrate any advantage for an intensive nutrition and exercise intervention over standard nutrition care in the first year after transplant. However, our findings suggest that standard nutrition care delivered by dietitians, including monitoring every 3 months, is associated with relatively modest increases in weight and body fat, compared to historically reported outcomes. Although our hypothesis was not proven, INTENT represents an important development in transplant clinical nutrition research and will inform the design of future studies. Further studies are needed to determine the optimal approach to avoid the adverse consequences of weight gain after transplant.”
- Excessive weight gain after kidney transplantation is a contributing factor to the increased risk of cardiovascular disease in kidney transplant recipients.
- Researchers conducted the INTENT (Intensive Nutrition Interventions on Weight Gain after Kidney Transplantation) trial to test the hypothesis that an intensive nutrition and exercise intervention would reduce post-transplant weight gain.
- There were no differences between the intervention group and the control group in the primary or secondary outcomes in the first year after kidney transplant; weight gain was relatively modest in both groups.