The iHealth-T2D study: rationale and design of a cluster randomised trial for prevention of Type 2 Diabetes amongst South Asians with central obesity and prediabetes

Abstract

BackgroundPeople from South Asia are at increased risk of type 2 diabetes (T2D). There is an urgent need to develop approaches for prevention of T2D in South Asians, that are cost-effective, generalisable and scalable across settings.HypothesisCompared to usual care, risk of T2D can be reduced amongst South Asians with central obesity or raised HbA1c, through a 12 month lifestyle modification programme delivered by community health workers.DesignCluster randomised clinical trial (1:1 allocation to Intervention or Usual care), carried out in India, Pakistan, Sri Lanka, and UK, with 30 sites per country (120 sites total). Target recruitment 3,600 (30 participants per site) with annual follow-up for three years.Entry criteriaSouth Asian, men or women, age 40-70 years with i. Central obesity (waist circumference ≥100cm in India and Pakistan; ≥90cm in Sri Lanka) and / or ii. Prediabetes (HbA1c 6.0-6.4% inclusive). Exclusion criteria: known type 1 or 2 diabetes, normal or underweight (body mass index<22kg/m2); pregnant or planning pregnancy; unstable residence or planning to leave the area; serious illness.EndpointsThe primary end point is new onset T2D at 3 years, defined as: i. HbA1c≥6.5% or ii. Physician diagnosis and on treatment for T2D. Secondary endpoints at 1 and 3 years are: i. Physical measures: waist circumference, weight and blood pressure; ii. Lifestyle measures: smoking status, alcohol intake, physical activity, dietary intake; iii. Biochemical measures: Fasting glucose, insulin and lipids (total and HDL cholesterol, triglycerides); and iv. Treatment compliance.InterventionLifestyle intervention (60 sites) or Usual care (60 sites). Lifestyle intervention was delivered by a trained community health worker over 12 months (5 one-one session, 4 group sessions, 13 telephone sessions) with the goal of the participants achieving e a 7% reduction in body mass index and a 10 cm reduction in waist circumference through i. improved diet and ii. increased physical activity. Usual care comprised a single 30 minute session of lifestyle modification advice from the community health worker.ResultsWe screened 33,212 people for inclusion into the study. We identified 10,930 people who met study entry criteria, amongst whom, 3,682 agreed to take part in the intervention. Study participants are 49.2% female and aged 52.8 (SD 8.2) years. Clinical characteristics are well balanced between Intervention and Usual care sites. More than 90% of follow-up visits are scheduled to be complete December 2020. Based on follow-up to end 2019, the observed incidence of T2D in the study population is in line with expectations (6.1% per annum).ConclusionThe iHealth-T2D study will advance understanding of strategies for prevention of diabetes amongst South Asians, use approaches for screening and intervention that are adapted for low-resource settings. Our study will thus inform the implementation of strategies for improving the health and well-being of this major global ethnic group.IRB approval16/WM/0171Trial registrationEudraCT 2016-001350-18. Registered 14 April 2016 https://www.hra.nhs.uk/planning-and-improving-research/application-summaries/research-summaries/ihealth-t2d/ ; ClinicalTrials.gov NCT02949739. Registered 31 October 2016, https://clinicaltrials.gov/ct2/show/NCT02949739, First posted 31/10/2016.FunderEuropean Commission (award 643774) and National Institute for Health Research (award 16/136/68)

Effects of a lifestyle intervention programme after 1 year of follow-up among South Asians at high risk of type 2 diabetes: a cluster randomised controlled trial

“…The key innovations making the intervention more scalable compared with previous work, which include identification of South Asians at increased risk of T2D based on waist circumference and HbA1c (HbA1c was recently used to identify participant populations for the first time in the Norfolk Diabetes Prevention Study), 12 and use of community health workers. A full description of the study design is available in Kasturiratne et al 13 In brief, a total of 120 sites from a range of socioeconomic settings and comprising both rural and urban were identified, with 30 sites in each of the four participating countries (India, Pakistan, Sri Lanka and the UK) were included. At each field-work location, we aimed to recruit 15 male and 15 female South Asians aged between 40 and 70 years, at high risk, but free from T2D.…”

“…A full description of the study design is available in Kasturiratne et al . 13 In brief, a total of 120 sites from a range of socioeconomic settings and comprising both rural and urban were identified, with 30 sites in each of the four participating countries (India, Pakistan, Sri Lanka and the UK) were included. At each field-work location, we aimed to recruit 15 male and 15 female South Asians aged between 40 and 70 years, at high risk, but free from T2D.…”

“…The primary aim of the lifestyle intervention sessions was the prevention of T2D, through >7% wt loss and ≥5 cm reduction in waist circumference. Details on the lifestyle intervention are described in Kasturiratne et al 13 and are also available on the study website ( www.ihealth-t2d.org ). In brief, participants in the intervention arm received family-based lifestyle modification (LSM) including all the core Diabetes Prevention Programme design elements.…”

“…The primary aim of the lifestyle intervention sessions was the prevention of T2D, through >7% wt loss and ≥5 cm reduction in waist circumference. Details on the lifestyle intervention are described in Kasturiratne et al 13 and are also available on the study website ( www. ihealth-t2d.…”