Does intensive diet and exercise counseling affect mortality in patients with prediabetes or type 2 diabetes?
In relatively young older people (if there is such a category), intensive lifestyle counseling regarding diet and physical activity produced no significant benefit on all-cause or cardiovascular mortality over an average 4.25 years of follow-up. There might be a benefit seen over longer periods, though the longest studies in this meta-analysis found no benefit over 16 to 21 years of follow-up.
Meta-analysis (randomized controlled trials)
To identify eligible studies, these researchers searched 4 databases, including Cochrane Central, as well as study trial registries, and reference lists, and contacted the authors of published and unpublished trials for unpublished data. They included all languages in their search. The studies must have enrolled patients with prediabetes or type 2 diabetes and included a dietary advice as the main treatment intervention along with physical exercise recommendations, which was compared with usual care or less intensive intervention. Five pairs of researchers independently selected studies for inclusion and abstracted the findings. Two researchers evaluated the studies for risk of bias, which was low for most studies. The authors identified 11 randomized controlled trials that compared intensive lifestyle interventions with usual care for at least 2 years (average = 4.25 years). Seven studies included patients with prediabetes and 4 studies included patients with diabetes. All but 1 study enrolled patients with a body mass index equating to overweight or obese.
In a total of 16,554 participants (mean age 55.5 years), the incidence of all-cause mortality was not different between intervention and control groups (relative risk [RR] 0.93; 95% CI 0.85 - 1.03). Similarly, in 11,017 participants (mean age 54.5 years), lifestyle interventions were not superior to usual care in reducing cardiovascular mortality (RR 0.99; 0.79 -1.23). There was minimal heterogeneity among the study results and no evidence of publication bias. Results were not substantially different when evaluating by study quality, glycemic status, age, or type of dietary and physical exercise recommendations.
Allen F. Shaughnessy, PharmD, MMedEd
Professor of Family Medicine