Lifestyle modification (LSM) and medication can prevent people at risk of diabetes from developing the condition in the short term, but only LSM is associated with a sustained risk reduction, according to a meta-analysis published Nov. 6 in JAMA Internal Medicine.

However, the benefit of LSM also declined over time, suggesting further interventions to preserve the effects are needed.

“Primary prevention of diabetes has proved to be cost-effective in various populations and settingsand is therefore crucial to reducing growing diabetes burdens,” wrote lead author J. Sonya Haw, MD, with the division of endocrinology at the Emory University School of Medicine, and colleagues. “Yet, translating these findings into practice remains a major challenge. … Lack of evidence on the long-term efficacy of diabetes prevention interventions may compromise policy-making guidance.”

The researchers extracted data from 43 studies encompassing 49,029 patients with prediabetes, defined as impaired glucose tolerance (IGT), impaired fasting glucose (IFG) or both, consistent with diagnostic criteria from the American Diabetes Association or World Health Organization. The average age of the study population was 57.3 and 52 percent of the patients were women.

At the end of the active intervention phase, LSM was associated with a 39 percent decreased risk of developing diabetes while medications were associated with a 36 percent decreased risk versus control participants.

After the intervention had ended and at a mean follow-up of 7.2 years, patients with a LSM were 28 percent less likely to have progressed to diabetes. Those receiving medications did not maintain a significant risk reduction following the intervention.

“Combined diet alterations and physical activity proved to be more effective in reducing progression to diabetes than either strategy alone,” the authors pointed out. “Since caloric intake and physical activity are independently associated with reduced diabetes risk, combining these may exert an additive effect.”

Haw et al. also identified which medications were most effective in reducing short-term risk of diabetes. Weight-loss drugs achieved the largest risk reduction (63 percent), followed by insulin sensitizers (53 percent), α-Glucosidase inhibitors (38 percent), a lipid-lowering drug (32 percent) and an insulin analogue (32 percent). Only one renin-angiotensin system blockade drug, valsartan, achieved a significant risk reduction of 10 percent, while hormone therapy and insulin secretagogues were not associated with significant risk reductions for diabetes.

“Diet with physical activity or weight loss and insulin-sensitizing medications prevent progression to diabetes in individuals at risk, with 25 persons needing to be treated to prevent a single diabetes case,” Haw and colleagues wrote. “Across all interventions, weight loss appears to be the key factor associated with reduced diabetes progression.”

The researchers noted each kilogram of weight lost was associated with an incremental 7 percent risk reduction for progressing to diabetes.

Future studies should focus on the cost-effectiveness of interventions and whether they result in different outcomes for patients with IGT alone, IFG alone or both, the authors wrote.