Effects of an individualized nutritional intervention on kidney function, body composition, and quality of life in kidney transplant recipients: Study protocol for a randomized clinical trial

Abstract

Background: Proteinuria after kidney transplantation (KTx) has been a frequent problem due to several factors, high protein intake being one of them. Individualized nutritional intervention in the late post-KTx period can promote the improvement or the reduction of risks associated with the parameters of evaluation of kidney function, body composition, and quality of life in individuals submitted to KTx.

Methods: This is a single-center, randomized and stratified clinical trial. The study will be conducted in a university hospital in northeastern Brazil with 174 individuals aged ≥19 years submitted to KTx and followed up for 12 months. Assessments will take place at 3-month intervals (T0, T3, T6, T9, and T12). The patients will be allocated to intervention and control groups by random allocation. The intervention group will receive individualized nutritional interventions with normoproteic diets (1.0 g/kg) after 60 days of KTx whereas the controls will receive the standard nutritional guidance for the post-KTx period. The primary efficacy variable is the change from baseline in log proteinuria assessed with the urinary albumin/creatinine ratio. Secondary efficacy variables include body composition, anthropometry, quality of life assessment and physical activity, lipid profile and glycemic control. Ninety-two subjects per group will afford 70% power to detect a difference of 25% between groups in log proteinuria. Primary efficacy analysis will be on the modified intention-to-treat population with between-groups comparison of the change from baseline in log proteinuria by analysis of covariance.

Discussion: The study will assess the effects of an individualized nutritional intervention on proteinuria 12 months after KTx.

Trial registration: REBEC (RBR-8XBQK5).

Fig 1. Flowchart in months with the design of the study from the recruitment of patients to data collection, considering the time of transplantation.

DXA, double-beam X-ray absorptiometry; SF-36, Medical Outcomes Study 36-Item Short-Form Health Survey; SRQ-20, Self-Reporting Questionnaire; IPAQ, International Physical Activity Questionnaire.

Fig 2. SPIRIT diagram.

*Time-points of the protocol: -T0, enrolment; T0, baseline; T60, 60th day after transplant; T3, month 3; T6, month 6; T9, month 9; T12, month 12. DXA, double-beam X-ray absorptiometry; SF-36, Medical Outcomes Study 36-Item Short-Form Health Survey; SRQ-20, Self-Reporting Questionnaire; IPAQ, International Physical Activity Questionnaire.