Comprehensive geriatric assessment for frail older people with chronic kidney disease to increase attainment of patient-identified goals: Statistical analysis plan for a cluster-randomised controlled trial

Background: Frailty is highly prevalent in older people with chronic kidney disease (CKD) and associated with more complex healthcare needs. As part of person-centred care, healthcare planning should be tailored to the individual's needs and their desired outcomes. Comprehensive Geriatric Assessment (CGA) is an intervention which can help facilitate this by identifying a person's medical, functional, and psychosocial problems, and then tailoring a coordinated, targeted management plan. The GOAL trial was designed to establish whether, compared to usual care, a CGA would better enable a person to achieve their own set goals, as measured by Goal Attainment Scaling (GAS). This paper presents the statistical analysis plan (SAP) for the GOAL trial. Methods: The GOAL trial is a pragmatic, multi-centre, superiority, open-label, cluster-randomised controlled trial designed to enrol 500 frail, older people (Frailty Index >0.25, aged ≥65 or ≥ 55 years if First Nations people) with moderate to severe CKD (estimated glomerular filtration rate < 59 mL/min/1.73m²) across 16 hospital sites in Australia, and 12 months of follow-up. The primary question (effect of CGA on GAS at 3 months) will be modelled using mixed-effects linear regression. The SAP details the analysis and reporting methods. Conclusions: The SAP described here resulted from an iterative, collaborative effort among statisticians and clinician leads of the GOAL trial. Specification of statistical methods prior to trial completion will contribute to unbiased analyses of the collected data. Trial registration: ClinicalTrials.gov