Trial of an individualised Intervention for the prevention of Stroke (TIIPS): Protocol and statistical analysis plan for a randomized controlled trial

RationaleUp to 90% of strokes are preventable through the modification and control of lifestyle risk factors. Health and Wellness (HWC) coaching is an established psychological intervention that may address multiple risk factors, including high blood pressure to reduce the risk of stroke. AimsTo determine the effectiveness of HWC in the management of blood pressure and stroke-related modifiable risk factors in reducing the risk of stroke. MethodsThis Phase III, open-label, single-blinded, two-arm randomised controlled trial recruited adults with first-ever or recurrent minor stroke or transient ischaemic attack from hospitals in Auckland and Hamilton, New Zealand. Eligible participants were [≥]18 years, independent in activities of daily living, had at least two modifiable cardiovascular risk factors, elevated or treated systolic blood pressure, were English-speaking, and had no history of major stroke, myocardial infarction, significant cognitive or mood disorders, or terminal illness. Longitudinal outcomes will be analysed using linear mixed-effects models under an intention-to-treat framework, with time-to-event outcomes analysed using competing-risk methods and missing data handled using multiple imputation with pooling based on Rubins rules. Study outcomesThe primary outcome is difference in the mean change from baseline systolic blood pressure (SBP) to 6-months post-randomisation between control (Usual Care, UC) and HWC groups. The study (n=360) is powered 85% (two sided =0.05) to detect a mean difference in change of SBP 6 mm Hg (SD {+/-} 20 mm Hg) between HWC and UC groups at 6-months post-randomisation, accounting for a 20% attrition rate. A revised sample size calculation due to a lower attrition rate (9%) provided a required sample size of 320. Secondary outcomes include cardiovascular health score using the Lifes Simple 7; stroke awareness; quality of life; satisfaction with life: cognition; mood; medication adherence; adverse cardiovascular events; health and service costs and productivity status. DiscussionHWC has the potential to modify lifestyle risk factors for stroke. This trial will be the first to test the effectiveness of HWC to modify lifestyle risk factors for secondary stroke prevention. Ethical approvalThe trial was approved by the New Zealand Health and Disability Ethics Committee (#2022 EXP 124562022), and The Auckland University of Technology Ethics Committee (#22/206). Trial registrationACTRN12622000939796 (registered 01/07/2022)