The iHealth-T2D study, prevention of type 2 diabetes amongst South Asians with central obesity and prediabetes: study protocol for a randomised controlled trial
Authors: Kasturiratne Anuradhani , Khawaja Khadija I. , Ahmad Sajjad , Siddiqui Samreen , Shahzad Khurram , Athauda Lathika K. , Jayawardena Ranil , Mahmood Sara , Muilwijk Mirthe , Batool Tayyaba , Burney Saira , Glover Matthew , Palaniswamy Saranya , Bamunuarachchi Vodathi , Panda Manju , Madawanarachchi Suren , Rai Baldeesh , Sattar Iqra , Silva Wnurinham , Waghdhare Swati , Jarvelin Marjo-Riitta , Rannan-Eliya Ravindra P. , Gage Heather M. , van Valkengoed Irene G. M. , Valabhji Jonathan , Frost Gary S. , Loh Marie , Wickremasinghe Ananda R. , Kooner Jaspal S. , Katulanda Prasad , Jha Sujeet , Chambers John C. 
Published: December 2021

Abstract
Background
People from South Asia are at increased risk of type 2 diabetes (T2D). There is an urgent need to develop approaches for the prevention of T2D in South Asians that are cost-effective, generalisable and scalable across settings.

Hypothesis
Compared to usual care, the 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.

Design
Cluster randomised clinical trial (1:1 allocation to intervention or usual care), carried out in India, Pakistan, Sri Lanka and the UK, with 30 sites per country (120 sites total). Target recruitment 3600 (30 participants per site) with annual follow-up for 3 years.

Entry criteria
South Asian, men or women, age 40–70 years with (i) central obesity (waist circumference ≥ 100 cm in India and Pakistan; ≥90 cm 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 < 22 kg/m2); pregnant or planning pregnancy; unstable residence or planning to leave the area; and serious illness.

Endpoints
The primary endpoint 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 the following: (i) physical measures: waist circumference, weight and blood pressure; (ii) lifestyle measures: smoking status, alcohol intake, physical activity and dietary intake; (iii) biochemical measures: fasting glucose, insulin and lipids (total and HDL cholesterol, triglycerides); and (iv) treatment compliance.

Intervention
Lifestyle intervention (60 sites) or usual care (60 sites). Lifestyle intervention was delivered by a trained community health worker over 12 months (5 one-one sessions, 4 group sessions, 13 telephone sessions) with the goal of the participants achieving 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-min session of lifestyle modification advice from the community health worker.

Results
We screened 33,212 people for inclusion into the study. We identified 10,930 people who met study entry criteria, amongst whom 3682 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 in December 2020. Based on the follow-up to end 2019, the observed incidence of T2D in the study population is in line with expectations (6.1% per annum).

Conclusion
The iHealth-T2D study will advance understanding of strategies for the 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 approval
16/WM/0171

Trial registration
EudraCT 2016-001350-18. Registered on 14 April 2016. ClinicalTrials.govNCT02949739. Registered on 31 October 2016, First posted on 31/10/2016.