The iHealth-T2D study: a cluster randomised trial for the prevention of type 2 diabetes amongst South Asians with central obesity and prediabetes—a statistical analysis plan
Mirthe Muilwijk,
Marie Loh,
Sara Mahmood,
Saranya Palaniswamy,
Samreen Siddiqui,
Wnurinham Silva,
Gary S. Frost,
Heather M. Gage,
Marjo-Riitta Jarvelin,
Ravindra P. Rannan-Eliya,
Sajjad Ahmad,
Sujeet Jha,
Anuradhani Kasturiratne,
Prasad Katulanda,
Khadija I. Khawaja,
Jaspal S. Kooner,
Ananda R. Wickremasinghe,
Irene G. M. van Valkengoed,
John C. Chambers
Affiliations
Mirthe Muilwijk
Department of Public Health, Amsterdam UMC, University of Amsterdam, Amsterdam Public Health Research Institute
Marie Loh
Lee Kong Chian School of Medicine, Nanyang Technological University
Sara Mahmood
Department of Endocrinology & Metabolism, Services Institute of Medical Sciences, Services Institute of Medical Sciences, Services Hospital
Saranya Palaniswamy
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, St Mary’s Campus, Norfolk Place
Samreen Siddiqui
Max Healthcare, Institute of Endocrinology, Diabetes and Metabolism, Max Super Speciality Hospital
Wnurinham Silva
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, St Mary’s Campus, Norfolk Place
Gary S. Frost
Faculty of Medicine, Imperial College London
Heather M. Gage
Department of Clinical and Experimental Medicine, Surrey Health Economics Centre, University of Surrey
Marjo-Riitta Jarvelin
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, St Mary’s Campus, Norfolk Place
Ravindra P. Rannan-Eliya
Institute for Health Policy
Sajjad Ahmad
Punjab Institute of Cardiology, Punjab Institute of Cardiology
Sujeet Jha
Max Healthcare, Institute of Endocrinology, Diabetes and Metabolism, Max Super Speciality Hospital
Anuradhani Kasturiratne
Faculty of Medicine, University of Kelaniya
Prasad Katulanda
Department of Clinical Medicine, Faculty of Medicine, University of Colombo
Khadija I. Khawaja
Department of Endocrinology & Metabolism, Services Institute of Medical Sciences, Services Institute of Medical Sciences, Services Hospital
Jaspal S. Kooner
London Northwest University Healthcare NHS Trust
Ananda R. Wickremasinghe
Faculty of Medicine, University of Kelaniya
Irene G. M. van Valkengoed
Department of Public Health, Amsterdam UMC, University of Amsterdam, Amsterdam Public Health Research Institute
John C. Chambers
Lee Kong Chian School of Medicine, Nanyang Technological University
Abstract Background South Asians are at high risk of type 2 diabetes (T2D). Lifestyle modification is effective at preventing T2D amongst South Asians, but the approaches to screening and intervention are limited by high costs, poor scalability and thus low impact on T2D burden. An intensive family-based lifestyle modification programme for the prevention of T2D was developed. The aim of the iHealth-T2D trial is to compare the effectiveness of this programme with usual care. Methods The iHealth-T2D trial is designed as a cluster randomised controlled trial (RCT) conducted at 120 sites across India, Pakistan, Sri Lanka and the UK. A total of 3682 South Asian men and women with age between 40 and 70 years without T2D but at elevated risk for T2D [defined by central obesity (waist circumference ≥ 95 cm in Sri Lanka or ≥ 100 cm in India, Pakistan and the UK) and/or prediabetes (HbA1c ≥ 6.0%)] were included in the trial. Here, we describe in detail the statistical analysis plan (SAP), which was finalised before outcomes were available to the investigators. The primary outcome will be evaluated after 3 years of follow-up after enrolment to the study and is defined as T2D incidence in the intervention arm compared to usual care. Secondary outcomes are evaluated both after 1 and 3 years of follow-up and include biochemical measurements, anthropometric measurements, behavioural components and treatment compliance. Discussion The iHealth-T2D trial will provide evidence of whether an intensive family-based lifestyle modification programme for South Asians who are at high risk for T2D is effective in the prevention of T2D. The data from the trial will be analysed according to this pre-specified SAP. Ethics and dissemination The trial was approved by the international review board of each participating study site. Study findings will be disseminated through peer-reviewed publications and in conference presentations. Trial registration EudraCT 2016–001,350-18 . Registered on 14 April 2016. ClinicalTrials.gov NCT02949739 . Registered on 31 October 2016.
