The exploration of an online intervention to prevent weight gain in new kidney transplant recipients

Student thesis: Doctoral ThesisDoctor of Philosophy


Although kidney transplantation is cost-effective and is the gold standard treatment for end-stage kidney disease, it is not without risk. Particularly in the first-year post transplantation, kidney transplant recipients (KTRs) are at risk of weight gain, which has been associated with adverse health outcomes. Weight gain appears to be a multifactorial problem for KTRs. The lifting of dialysis dietary interventions, the increase in appetite from anti-rejection medications, reduced physical activity and impaired physical function contribute to this clinical issue. Recent clinical guidelines stipulate KTRs should have access to specialist healthcare professionals (HCPs) to address weight gain in kidney transplant care. However, there are no recognised interventions to address weight gain prevention in the first-year post kidney transplantation.

A narrative systematic review (including16 studies) and meta-analysis (including ten randomised controlled trials (RCTs) (study 1, chapter 2) was conducted to examine the effect of exercise, physical activity, dietary and/or combined interventions on body weight and body mass index (BMI) within the first year of kidney transplantation. The results suggest limited research in this field, with variable study quality, variation in intervention design and delivery, making a pooled effect analysis challenging. Post-hoc exploratory analysis suggests combined complex interventions, with physical activity, dietary advice and behaviour change techniques (BCT’s) warrant further research in future RCTs.

The research fellow led a multi-professional research team, including KTRs, and input from a software company to create a bespoke online intervention to address weight gain in new KTRs, called the ExeRTiOn online intervention. A combined intervention design was used, with the person-based approach at the centre. This ensured the target end user of the product (new KTRs) was at the centre of the design, development and evaluation of the online intervention.

A qualitative study (study 2, chapters 3 and 4) was conducted in a purposive sample of 11 new KTRs and 6 transplant HCPs to capture the usability (functionality, navigation and engagement) and experience of using the ExeRTiOn prototype online intervention. Results from this published study (chapter 4) facilitated iterative and person-based revisions of the ExeRTiOn online intervention using a recognised digital intervention prioritisation tool.

A mixed methods feasibility RCT (studies 3 and 4, chapter 6) recruited a new sample of seventeen acute KTRs to assess the feasibility of conducting a RCT using the revised ExeRTiOn online intervention, compared with usual care. The primary outcomes addressed the feasibility of conducting the study (screening, recruitment, adherence, retention, hospitalisations etc) and using the revised ExeRTiOn online intervention. Quantitative data captured secondary outcomes including body weight, BMI, physical function, self-reported physical activity, self-efficacy, fatigue and quality of life (study 3) at baseline, 3-months and 12-months. A nested qualitative study (study 4, chapter 6) captured the experiences of trial participation, and using the online intervention. A convergent integrated mixed methods analysis (chapter 6) was performed on quantitative (study 3) and qualitative (study 4) datasets. The overall feasibility was assessed against pre-set progression criteria. The results of this study suggest the trial was feasible, the intervention was acceptable to our sample of KTR participants, and a post-PhD multicentre pilot RCT is warranted. Secondary outcome data suggest the online IG appeared to maintain median body weight across the study; 94.5kg, (IQR 63.0, 102.0) at baseline, 95.0kg, (IQR 66.7, 105.3) at 3-months and 94.7kg (IQR 77,2, 117.3) at 12- months. Whereas usual care participants increased body weight, 81.3kg, (IQR 73.6,94.6) at baseline, 86.2kg (75.4, 96.5) at 3-months and 93.3kg (70.3, 101.9) at 12-months. The IG increased six-minute walk distance (6MWD) over the three timepoints (450m, (IQR 450, 540), 525m (IQR 472.5, 615) and 495m (IQR 465, 615). The usual care group decreased 6MWD (517.5m (IQR 436, 570), 507.5m (IQR 442.5, 605) and 435m (IQR 435, 555)). All other outcomes were comparable across the sample.

The results and work presented in this thesis provide novel contributions to the evidence base. The systematic review (study 1) is the first to include combined interventions, as well as single arm interventions such as dietary or exercise interventions. Studies 2, 3 and 4 provide transparent reporting of the design, development, usability testing, and feasibility evaluation of a new online intervention to address weight gain in new KTRs. A follow-up multi-centre pilot RCT is planned. Future research is required to explore the effectiveness and cost-effectiveness of weight gain prevention interventions for new KTRs.
Date of Award1 Mar 2022
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorSharlene A. Greenwood (Supervisor), Joseph Chilcot (Supervisor) & Kate Bramham (Supervisor)

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