Randomized Clinical Trial of Lifestyle Interventions to Prevent Diabetes in Women With Previous Gestational Diabetes

LINDA-Brasil is a multicenter randomized clinical trial to test the effectiveness of a lifestyle intervention program tailored to women with a recent diagnosis of GDM to be implemented within two-year after pregnancy with the goal of preventing type 2 diabetes. It is based on a cohort study of women recruited during pregnancy. At first contact, the study protocol is explained, and it is made clear that not all women enrolled in the cohort will be eligible to participate in the post partum clinical trial. During pregnancy and the immediate post-partum period, women are monitored monthly by telephone to maintain contact. From six weeks to two years after delivery, high risk status is determined and women at high risk are contacted to evaluate their eligibility for the trial. Those potentially eligible are then invited to the research center for an examination prior to randomization. Once eligibility is confirmed, women return to the clinical research center at which point key aspects of the clinical trial protocol are reviewed and remaining questions clarified. Those willing to participate provide specific informed consent and are then allocated to one of the two comparison groups. The randomization scheme is 1:1 by trial arm, stratified by center and has random blocks. Based on results of key previous clinical trials on diabetes prevention, LINDA has tailored its intervention to meet the particular needs of women with previous GDM during their post partum. Building from social cognitive theory, interventions are participant-centered, allowing adaptation to each women´s setting, within the limits of a standardized prevention program with defined goals and structure. Communication strategies are based on motivational interviewing and health coaching approaches that can be implemented in the primary care setting. Follow-up is planned to continue until all women have completed at least 18 months of participation and the average length of follow up for the whole sample is at least three years. Outcomes are assessed at baseline, at 6 months and then annually. Women who develop diabetes will be notified and oriented to seek medical treatment.

Inclusion criteria

• Women aged 18 or older having gestational diabetes, regardless of the diagnostic criteria, who used insulin during their pregnancy or were found to have impaired glucose tolerance or impaired fasting glucose (>=100 mg/dL) on a post-partum oral glucose tolerance test (OGTT).
• We amended the protocol to also include women using oral hypoglycemics during pregnancy because their use increased during the trial implementation.

Exclusion criteria

• Confirmed postpartum diabetes (two abnormal OGTTs) or current use of antidiabetic medication
• Indication that the trial interventions will not be feasible, for example, distance from the trial site
• Poor attendance/response in previous contacts (appointments or phone interviews)
• Health limitations or treatments (assessed by questionnaire) restricting the nutritional intervention or the ability to practice physical activity, affecting glucose tolerance or limiting participation or survival.