The effect of intensive nutrition interventions on weight gain after kidney transplantation: A randomised controlled trial

Abstract

Background and aim: Weight gain and obesity are common after kidney transplantation, particularly during the first year. Obesity is a risk factor for new-onset diabetes after transplantation and reduced graft survival. There is limited evidence for effective nutrition interventions after kidney transplantation. The effect of INTEnsive Nutrition interventions on weight gain after kidney Transplantation (INTENT) trial was a single-centre, assessor-blinded, randomised controlled trial. The primary aim was to evaluate the effect of intensive nutrition intervention, including physical activity advice, on weight gain during the first year following kidney transplantation. Methods: Participants were randomised during the first month post-transplant to either intensive nutrition intervention or standard care. Intensive group participants received individualised nutrition and exercise counselling (eight visits with a renal dietitian over the first six months, four visits over the second six months, and three visits over the first six months with an exercise physiologist). Standard group participants received nutrition care as per guideline recommendations (four renal dietitian visits over 12 months). Formal assessment was undertaken at baseline, 3, 6 and 12 months post-transplant. The primary outcome was weight at six months post-transplant, adjusted for baseline weight, obesity and gender (analysis of covariance (ANCOVA)). Secondary outcomes included changes in weight and other anthropometric outcomes over 12 months, body composition (dual-energy X-ray absorptiometry, in vivo neutron activation, total body potassium, and bioelectrical impedance), biochemistry (haemoglobin A1c, fasting glucose, lipids and insulin), quality of life (Short Form-36), dietary intake and nutritional status, and physical function. Results: Thirty-seven transplant recipients were randomised (19 intensive; 18 standard). One participant withdrew pre-intervention and was excluded from analysis. Weight increased from baseline to six months (78.0 ± 13.7kg to 79.6 ± 13.0kg; p = 0.007), but six-month weight did not differ significantly between the groups (77.0 ± 12.4kg (intensive); 82.2 ± 13.4kg (standard); adjusted p = 0.749, ANCOVA). Over 12 months, total body protein (p = 0.008), physical function (gait-speed, sit-to-stand-to-sit test, grip strength (all p <0.001)), and physical activity (p <0.001) improved. HbA1c (p = 0.028) and fasting glucose (p = 0.026) increased at three months and stabilised by six months. Quality of life improved in all domains (all p <0.003), with the exception of General Health and Mental Health. No significant between-group differences were seen in these secondary outcomes. Conclusions: Post-transplant weight gain was modest in both groups. There was no advantage with a more intensive nutrition intervention over standard care.