Factors affecting weight gain following renal transplant in paediatric patients at Starship Child Health

Abstract

Background: Weight gain and obesity are common following paediatric renal transplant. Several factors are reported to influence weight gain in children post renal transplant; however, results are mostly inconclusive, and the knowledge of the determinants of weight gain in the New Zealand population is lacking. This study aimed to describe longitudinal growth and weight post-transplant in New Zealand paediatric renal transplant patients and determine any risk factors that could predict excessive weight gain. The secondary aim was to understand the barriers and facilitators to nutrition care. Methods: A mixed-methods study design was employed. A retrospective clinical record audit of all renal transplants performed at Starship Child Health, between September 2008 and April 2021, was conducted. Patient demographics, anthropometry, biochemical and nutrition data were collected to determine any relationships between growth and weight parameters and patients' clinical and demographic variables. Patients were grouped according to a change in steroid dose regimen that occurred in November 2012. A random-effects mixed model was used to evaluate changes in anthropometric (z-scores) and biochemical variables post-transplant. Multiple comparisons were performed post hoc to compare changes since transplant within each steroid pathway. Multivariate linear regression was used to identify independent factors associated with overweight and obesity at specific time points. Semi-structured interviews were conducted with patients and their families/whānau, and inductive thematic analysis was performed to identify themes. Results: Seventy-nine renal transplants were performed between September 2008 and April 2021. Recipients were between one and 16 years of age. At the time of transplant, 15.9% of children were overweight, and 13% were obese, increasing to a combined prevalence of 47% at three months post-transplant. No significant group-by-time interaction was seen for any anthropometric variables. Māori and Pacific children had increased odds of being overweight or obese at transplant (OR: 6.841; 95% CI: 1.105, 42.360; p=0.039 and OR: 19.078; 95% CI: 2.116, 171.995; p=0.009, respectively), compared to non- Māori and non-Pacific children, and this persisted in Pacific children at six months post-transplant (OR: 6.55; 95% CI: 1.135, 37.750; p=0.036). Male patients had an increased odds of being overweight or obese at transplant (OR: 11.79; 95% CI: 1.973, 70.496; p=0.007) compared to female patients. Five semi-structured interviews were completed, and key themes included a lack of practical and culturally specific advice. Conclusion: Rapid weight gain was observed in the initial months post-transplant. Male sex, Māori and Pacific ethnicity were identified as risk factors for overweight and obesity at transplant, and risk persisted in those of Pacific ethnicity at six months following transplant. Semi-structured interview findings highlighted a need for more practical advice post-transplant and more culturally specific nutritional care to better support healthy eating practices in these patients.