Periodic Reporting for period 4 - iHealth-T2D (Family-based intervention to improve healthy lifestyle and prevent Type 2 Diabetes amongst South Asians with central obesity and prediabetes)
Période du rapport: 2019-01-01 au 2019-12-31
South Asians, who represent one-quarter of the world’s population, are at high risk of type-2 diabetes. India alone has ~56 million people with T2D, the second highest number in the world. Conservative estimates based on population growth, ageing and rates of urbanisation show that T2D cases in India will increase to ~100 million by 2030. T2D prevalence is currently ~9% in rural India, ~18% in urban India, and ~22% amongst Indians living in Europe (compared to ~6% among Europeans). Similar patterns are observed among South Asians in Pakistan, Bangladesh, and Sri Lanka. Diabetes poses a massive clinical, economic and social burden among South Asian countries as well as in the European countries to which South Asians have emigrated in large numbers. Our general goal is to identify approaches to risk stratification and health promotion through lifestyle modification that are acceptable, effective and efficient for prevention of T2D in South Asian communities from diverse settings. To achieve this, the iHealth-T2D study will investigate whether intensive lifestyle modification vs usual care reduces risk of T2D (primary endpoint) amongst South Asians with i. central obesity; ii. pre-diabetes and iii. overall (with central obesity and / or obesity). In addition, we will investigate health gains amongst family members, and complete a health economic analysis to quantify the cost-effectiveness of screening by waist circumference vs HbA1c, and of lifestyle modification for prevention of T2D, on the Indian subcontinent and Europe. The study aims to recruit 3,600 South Asian men and women aged 40-70 years with i. central obesity (waist≥100 cm) and/or ii. pre-diabetes (HbA1c 6.0-6.4%) to the study (Index cases). Recruitment was carried out in India, Pakistan, Sri Lanka and UK. Index cases received either i. intensive lifestyle modification; or ii. usual care (Total N=3,670). Intensive lifestyle modification followed clinically accepted, evidence based strategies to achieve >7% reduction in weight through improved diet and increased physical activity, and was delivered as 9 face-face and 13 telephone contact sessions over 12 months. Participants re being followed annually for 3 years to ascertain. The primary analyses will determine the clinical and cost-effectiveness of intensive lifestyle modification vs usual care for prevention of T2D amongst South Asians with i. central obesity; ii. pre-diabetes or iii, overall. Secondary analyses will address behavioural, psychosocial, clinical, and biochemical measures similarly. Health economic analyses will take account of costs incurred by the government, and participants. Effectiveness will be measured in terms of screening numbers needed to identify one case of ‘high risk’ for developing diabetes, and numbers needed to treat to prevent or delay one case of diabetes. Sensitivity analysis will be undertaken to test the robustness of the analysis in terms of the cost inputs and health outcomes.
-Adaptation and translation of dietary intervention protocols: The dietary documents were developed by the study nutritionists in collaboration with the nutritionists of the 3 countries. All documents were adapted and tailored to each country’s reality and food culture. This proved to be a substantial piece of work, with more than 30 documents translated into major South Asian languages. This represents ~240 separate documents that are a unique resource for health promotion in this high-risk population.
- Training and Piloting: study dieticians, CHW and supporting staff received intensive training which were organised in the 4 countries and delivered by each country’s dietician with the support of UK’s dietician. Additionally, screening, recruitment and clinic visits were piloted in all 4 countries, which allowed to identify and resolve potential problems and facilitated training of the staff involved in the study.
- Field work sites selection: The 120 field-work sites (30 in each country) were identified in 2015.
- Study database: A database has been custom written for storage and reporting on clinical data at a local level.
- Regulatory approval: Regulatory approval was obtained in all recruitment institutions between March and May 2016.
- Screening, enrolment and intervention: All sites achieved a total of 25,453 screened people, of whom 4,263 meet study entry criteria and are eligible for the study intervention. Of these, 3,670 were recruited into the intervention phase of the study (mean 30 people per site). These figures are in line with expectations in the project proposal.
- Intervention was successfully delivered to participants. Attendance rates were in line with expectations, and published experience.
- Follow-up: Index cases and their relatives were invited to attend follow-up annually after enrolment to the study. Follow-up year 1 was concluded in October 2018. Preliminary analyses by the trial statistical team suggest that the incidence of diabetes is in line with expectation, and that sample size remains appropriate. Final follow-up (Year 3) is expected to be completed in October 2020.
- Analysis: the statistical analysis plan has been finalised and submitted for publication. Analysis of the primary outcome (diabetes) will be carried out after Year 3 data are available. Preliminary analyses of clinical-effectiveness for secondary endpoints have been carried out using data from year 1 of follow-up. Costs effectiveness analyses have quantified the costs of screening, and have modelled the cost-effectiveness for intervention under a range of assumptions for outcomes.
- Training and Piloting: study dieticians, CHW and supporting staff received intensive training which were organised in the 4 countries and delivered by each country’s dietician with the support of UK’s dietician. Additionally, screening, recruitment and clinic visits were piloted in all 4 countries, which allowed to identify and resolve potential problems and facilitated training of the staff involved in the study.
- Field work sites selection: The 120 field-work sites (30 in each country) were identified in 2015.
- Study database: A database has been custom written for storage and reporting on clinical data at a local level.
- Regulatory approval: Regulatory approval was obtained in all recruitment institutions between March and May 2016.
- Screening, enrolment and intervention: All sites achieved a total of 25,453 screened people, of whom 4,263 meet study entry criteria and are eligible for the study intervention. Of these, 3,670 were recruited into the intervention phase of the study (mean 30 people per site). These figures are in line with expectations in the project proposal.
- Intervention was successfully delivered to participants. Attendance rates were in line with expectations, and published experience.
- Follow-up: Index cases and their relatives were invited to attend follow-up annually after enrolment to the study. Follow-up year 1 was concluded in October 2018. Preliminary analyses by the trial statistical team suggest that the incidence of diabetes is in line with expectation, and that sample size remains appropriate. Final follow-up (Year 3) is expected to be completed in October 2020.
- Analysis: the statistical analysis plan has been finalised and submitted for publication. Analysis of the primary outcome (diabetes) will be carried out after Year 3 data are available. Preliminary analyses of clinical-effectiveness for secondary endpoints have been carried out using data from year 1 of follow-up. Costs effectiveness analyses have quantified the costs of screening, and have modelled the cost-effectiveness for intervention under a range of assumptions for outcomes.
This study will describe the clinical and cost-effectiveness of lifestyle intervention using a family based approach for prevention of T2D amongst prediabetic or centrally obese South Asians. Results will be used to describe the potential implications (benefits and costs), in the local and national health economies, of scaling-up intensive lifestyle modification for prevention of T2D, using central obesity and/or HbA1c for screening, considering gender and different environmental settings. In the longer term, we expect our study to have potential for a major impact on the burden of T2D in South Asians. As early outputs, the project has enabled development of a comprehensive, fully adapted set of materials for lifestyle intervention to prevent T2D amongst SA men and women from diverse settings. These materials alone represent a valuable clinical resource that will benefit South Asians and the health systems of the countries they live in. Additionally, we have collected a rich dataset of information on health and lifestyle (diet and physical activity), with supporting biological samples, to better understand the patterns or chronic disease in SA populations. Engagement with our study has stimulated interest in the partner South Asian countries to advance and better implement measures for prevention of T2D. As a direct result, diabetes action plans have been developed in partner countries. This progress towards wider implementation of measures for prevention of T2D, embedding our work into policy and practice, represents a major early win for the study. Our work has provided the experience and stimulus for the next generation of translational clinical research in South Asia, including the NIHR funded Global Health Research Unit for Diabetes and Cardiovascular disease in South Asians, and the South Asia Biobank Study, funded by Wellcome Trust.