A peer-support lifestyle intervention for preventing type 2 diabetes in India: A cluster-randomized controlled trial of the Kerala Diabetes Prevention Program

Background
The major efficacy trials on diabetes prevention have used resource-intensive approaches to identify high-risk individuals and deliver lifestyle interventions. Such strategies are not feasible for wider implementation in low- and middle-income countries (LMICs). We aimed to evaluate the effectiveness of a peer-support lifestyle intervention in preventing type 2 diabetes among high-risk individuals identified on the basis of a simple diabetes risk score.
Methods and findings
The Kerala Diabetes Prevention Program was a cluster-randomized controlled trial conducted in 60 polling areas (clusters) of Neyyattinkara taluk (subdistrict) in Trivandrum district, Kerala state, India. Participants (age 30–60 years) were those with an Indian Diabetes Risk Score (IDRS) ≥60 and were free of diabetes on an oral glucose tolerance test (OGTT). A total of 1,007 participants (47.2% female) were enrolled (507 in the control group and 500 in the intervention group). Participants from intervention clusters participated in a 12-month community-based peer-support program comprising 15 group sessions (12 of which were led by trained lay peer leaders) and a range of community activities to support lifestyle change. Participants from control clusters received an education booklet with lifestyle change advice. The primary outcome was the incidence of diabetes at 24 months, diagnosed by an annual OGTT. Secondary outcomes were behavioral, clinical, and biochemical characteristics and health-related quality of life (HRQoL). A total of 964 (95.7%) participants were followed up at 24 months. Baseline characteristics of clusters and participants were similar between the study groups. After a median follow-up of 24 months, diabetes developed in 17.1% (79/463) of control participants and 14.9% (68/456) of intervention participants (relative risk [RR] 0.88, 95% CI 0.66–1.16, p = 0.36). At 24 months, compared with the control group, intervention participants had a greater reduction in IDRS score (mean difference: −1.50 points, p = 0.022) and alcohol use (RR 0.77, p = 0.018) and a greater increase in fruit and vegetable intake (≥5 servings/day) (RR 1.83, p = 0.008) and physical functioning score of the HRQoL scale (mean difference: 3.9 score, p = 0.016). The cost of delivering the peer-support intervention was US$22.5 per participant. There were no adverse events related to the intervention. We did not adjust for multiple comparisons, which may have increased the overall type I error rate.
Conclusions
A low-cost community-based peer-support lifestyle intervention resulted in a nonsignificant reduction in diabetes incidence in this high-risk population at 24 months. However, there were significant improvements in some cardiovascular risk factors and physical functioning score of the HRQoL scale.
Trial registration
Australia and New Zealand Clinical Trials Registry ACTRN12611000262909.

# 研究背景
现有糖尿病预防主要疗效试验均采用资源密集型方法来识别高危个体并实施生活方式干预。此类策略难以在低收入和中等收入国家（low- and middle-income countries, LMICs）中大范围推广应用。本研究旨在评估基于简易糖尿病风险评分识别的高危人群中，同伴支持式生活方式干预对预防2型糖尿病的效果。

## 研究方法与结果
本研究的喀拉拉邦糖尿病预防项目是在印度喀拉拉邦特里凡得琅县内亚塔廷卡拉乡的60个投票区（整群）开展的整群随机对照试验。研究纳入年龄30~60岁、印度糖尿病风险评分（Indian Diabetes Risk Score, IDRS）≥60分且经口服葡萄糖耐量试验（oral glucose tolerance test, OGTT）确认未患糖尿病的个体。最终共纳入1007名受试者（女性占47.2%），其中对照组507人，干预组500人。
干预组受试者参与为期12个月的社区同伴支持项目，该项目包含15次团体课程（其中12次由经过培训的非专业同伴带头人主持）及一系列助力生活方式改变的社区活动。对照组受试者则获赠一份包含生活方式改变建议的教育手册。
本研究的主要结局指标为随访24个月时的糖尿病发病率，诊断方式为每年一次的OGTT。次要结局指标包括行为、临床及生化特征，以及健康相关生活质量（health-related quality of life, HRQoL）。最终共有964名受试者（占比95.7%）完成24个月随访。
两组的整群及受试者基线特征均无显著差异。中位随访24个月后，对照组受试者中17.1%（79/463）新发糖尿病，干预组为14.9%（68/456）（相对风险（relative risk, RR）0.88，95%置信区间0.66~1.16，p=0.36）。随访24个月时，与对照组相比，干预组受试者的IDRS评分（均数差：-1.50分，p=0.022）与饮酒率（RR 0.77，p=0.018）降幅更显著，果蔬摄入量（≥5份/天）的提升率（RR 1.83，p=0.008）以及HRQoL量表的躯体功能评分（均数差：3.9分，p=0.016）提升更明显。该同伴支持式干预的人均实施成本为22.5美元。本研究未针对多重比较进行校正，这可能会升高整体Ⅰ类错误率。

## 研究结论
低成本社区同伴支持式生活方式干预虽未使该高危人群在24个月时的糖尿病发病率出现显著降低，但显著改善了部分心血管危险因素及HRQoL量表的躯体功能评分。

## 试验注册
澳大利亚与新西兰临床试验注册平台（Australia and New Zealand Clinical Trials Registry）编号：ACTRN12611000262909。