medwireNews: Lifestyle interventions to delay the onset of type 2 diabetes result in marked long-term reductions in cardiovascular disease (CVD) and mortality, shows the 30-year follow-up of the Da Qing Diabetes Prevention Outcome Study.
Overall, nine people needed to receive a lifestyle intervention to prevent one CVD event during the following 30 years, Guangwei Li (China–Japan Friendship Hospital, Beijing) and co-workers report in The Lancet Diabetes & Endocrinology.
And mortality from any cause was delayed by a median of 4.82 years, equating to an average 1.44 additional years of life expectancy.
The authors of a linked commentary – Michael Lean and Naveed Sattar from the University of Glasgow, UK – observe that the study participants were relatively young at inclusion, being aged around 45 years, on average, when they were diagnosed with impaired glucose tolerance.
Noting that type 2 diabetes has a particularly aggressive course when diagnosed young, they say that “a modest delay in diabetes onset, when it occurs in the mid-40s, could benefit life expectancy.”
They add: “The corollary is that interventions in older people, in whom type 2 diabetes is still most common, would be less likely to have such an effect, because onset beyond the age of 75–80 years has little effect on life expectancy.”
The 438 people assigned to participate in an intervention group received either a diet or exercise intervention, or the two combined, for 6 years. An additional 138 people were assigned to the control group and given usual care, and 405 and 135 people from the intervention and control groups, respectively, were assessed for outcomes at 30 years.
By the end of the 30-year follow-up, more than 80% of all participants had developed diabetes, regardless of whether they received a lifestyle intervention. However, those in the intervention group had a significantly lower cumulative diabetes incidence, with a 39% reduced risk relative to the control group, and they developed it a median of 3.96 years later.
Around half of the study participants had CVD events during follow-up, but there were significantly fewer events in the intervention than control groups, at cumulative incidences of 52.9% versus 66.5%, giving a 26% reduction in the intervention group. Moreover, the intervention resulted in a median delay of 4.64 years to first CVD event.
The incidences of individual macrovascular endpoints were reduced by a significant 25% for stroke and a nonsignificant 27% and 29% for coronary heart disease and hospitalization for heart failure, respectively. There was also a significant 35% reduction in the risk for microvascular disease.
Of note, the researchers found that adjusting for the time of diabetes onset eliminated the positive effect of the intervention on CVD and mortality outcomes, which Lean and Sattar say “makes sense, because there is an escalation in vascular risk when people transition from prediabetes to diabetes.”
The commentators conclude: “The total available evidence thus shows that efforts at both ends of the type 2 diabetes disease course—lifestyle interventions to prevent diabetes and new drugs in patients with diabetes and established cardiovascular disease—are worthwhile.
“Of course, it would be better from any perspective to prevent diabetes in the first place, and delay cardiovascular outcomes, than to treat more with drugs at later stages when patients already have debilitating illness.”
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Lancet Diabetes Endocrinol 2019; doi:10.1016/S2213-8587(19)30093-2
Lancet Diabetes Endocrinol 2019; doi:10.1016/S2213-8587(19)30138-X