Do lifestyle interventions reduce diabetes incidence in people with isolated impaired fasting glucose?

Test and Treat for Prediabetes: A Review of the Health Effects of Prediabetes and the Role of Screening and Prevention

The term prediabetes describes blood glucose levels above the normal range but below the threshold to diagnose type 2 diabetes. Several population health initiatives encourage a test and treat approach for prediabetes. In this approach, screening and identification of individuals with prediabetes should be followed by prompt referral to structured lifestyle modification programs or pharmacologic interventions that have been shown to prevent or delay the progression to type 2 diabetes in clinical trials. Here we provide a critical review of evidence for this test and treat approach by examining health outcomes associated with prediabetes and the availability and effectiveness of lifestyle modification approaches that target prediabetes. We also describe current limitations to the reach and uptake of evidence-based treatment options for prediabetes. Finally, we highlight lessons learned from identifying and labeling other preconditions to consider challenges and opportunities that may arise with increasing awareness of prediabetes as part of routine preventive care.

Low-calorie diets for people with isolated impaired fasting glucose

Thirunavukkarasu et al. discuss how standard lifestyle interventions prove ineffective in preventing type 2 diabetes in individuals with isolated impaired fasting glucose, a highly prevalent prediabetes phenotype globally. They propose low-calorie diets as a promising strategy for diabetes prevention in this high-risk population.

Does the Effect of a 3-Year Lifestyle Intervention on Body Weight and Cardiometabolic Health Differ by Prediabetes Metabolic Phenotype? A Post Hoc Analysis of the PREVIEW Study

OBJECTIVE

To examine whether the effect of a 3-year lifestyle intervention on body weight and cardiometabolic risk factors differs by prediabetes metabolic phenotype.

RESEARCH DESIGN AND METHODS

This post hoc analysis of the multicenter, randomized trial, PREVention of diabetes through lifestyle interventions and population studies In Europe and around the World (PREVIEW), included 1,510 participants with prediabetes (BMI ≥25 kg ⋅ m-2; defined using oral glucose tolerance tests). Of these, 58% had isolated impaired fasting glucose (iIFG), 6% had isolated impaired glucose tolerance (iIGT), and 36% had IFG+IGT; 73% had normal hemoglobin A1c (HbA1c; <39 mmol ⋅ mol-1) and 25% had intermediate HbA1c (39-47 mmol ⋅ mol-1). Participants underwent an 8-week diet-induced rapid weight loss, followed by a 148-week lifestyle-based weight maintenance intervention. Linear mixed models adjusted for intervention arm and other confounders were used.

RESULTS

In the available-case and complete-case analyses, participants with IFG+IGT had greater sustained weight loss after lifestyle intervention (adjusted mean at 156 weeks -3.5% [95% CI, -4.7%, -2.3%]) than those with iIFG (mean -2.5% [-3.6%, -1.3%]) relative to baseline (P = 0.011). Participants with IFG+IGT and iIFG had similar cardiometabolic benefits from the lifestyle intervention. The differences in cardiometabolic benefits between those with iIGT and IFG+IGT were minor or inconsistent in different analyses. Participants with normal versus intermediate HbA1c had similar weight loss over 3 years and minor differences in cardiometabolic benefits during weight loss, whereas those with normal HbA1c had greater improvements in fasting glucose, 2-h glucose (adjusted between-group difference at 156 weeks -0.54 mmol ⋅ L-1 [95% CI -0.70, -0.39], P < 0.001), and triglycerides (difference -0.07 mmol ⋅ L-1 [-0.11, -0.03], P < 0.001) during the lifestyle intervention.

CONCLUSIONS

Individuals with iIFG and IFG+IGT had similar improvements in cardiometabolic health from a lifestyle intervention. Those with normal HbA1c had greater improvements than those with intermediate HbA1c.

Effectiveness and implementation of a lifestyle modification intervention for women with isolated impaired fasting glucose: Study protocol for a hybrid type 2 study in Kerala, India

Background: Isolated impaired fasting glucose (i-IFG) constitutes a major group in the prediabetic spectrum among Indians, and thus it is imperative to identify effective diabetes prevention strategies. This study aims to evaluate the effects of an intensive community-based lifestyle modification program on regression to normoglycemia among women with i-IFG, compared to a control group at 24 months. The study also aims to evaluate the implementation of the intervention, via both process and implementation outcomes. Methods: We will use a hybrid design (Effectiveness-implementation hybrid type 2 trial) to test the effectiveness and implementation of the lifestyle modification intervention. Effectiveness is evaluated using a randomized controlled trial among 950 overweight or obese women, aged 30 to 60 years, with i-IFG on an oral glucose tolerance test in the Indian state of Kerala. The intervention involves an intensive lifestyle modification program through group and individually mentored sessions using behavioural determinants and behavioural change techniques.  The intervention group will receive the intervention for a period of 12 months and the control group will receive general health advice through a health education booklet. Data on behavioural, clinical, and biochemical measures will be collected using standard methods at 12 and 24 months. The primary outcome will be regression to normoglycemia at 24 months, as defined by the American Diabetes Association criteria. Discussion: This study will provide the first evidence on the effects of lifestyle interventions on regression to normoglycemia in people with i-IFG among Indians. CTRI registration: CTRI/2021/07/035289 (30/07/2021).