Upping Physical Activity Slashes CV Events, Deaths in Type 2 Diabetics

Shelley Wood

October 02, 2012

October 2, 2012 (Berlin, Germany) — Not surprisingly, higher levels of leisure-time physical activity cut the risk of cardiovascular and all-cause mortality in people with type 2 diabetes, a new analysis from the Swedish National Diabetes Register (NDR) shows [1]. But in an important additional finding, researchers report that among diabetics who did little or no exercise at baseline, those who managed to substantially increase their leisure-time physical-activity levels over approximately five years cut their risk of death by almost two-thirds.

Dr Björn Zethelius (Uppsala University, Sweden) presented the study findings here at the European Association for the Study of Diabetes (EASD) 2012 Meeting.

"We consider physical activity and dietary advice as the basal treatment for diabetes, and when it fails, different types of pharmacological treatment are added," Zethelius told heartwire . "But what this study shows is that it's never too late to increase your physical activity. Even when you are on medication, if you increase your physical activity, you will lower your risk for cardiovascular diseases. I think that's the [important] message."

Zethelius and colleagues used data on leisure-time physical activity, recorded yearly, from the more than 15 000 men and women with type 2 diabetes in the NDR. Participants were grouped as either "low physical activity" (no regular exercise or exercise once per week) or "regular exercise" (between three times per week and daily exercise). If patients died during the course of the study, their last recorded physical-activity level was used for the analysis.

Over a five-year period, regular exercisers were significantly less likely to have a cardiovascular event or to die either from cardiovascular disease or any other cause.

Hazard Ratios (95% CI) for Adverse Events According to Exercise Levels*

End point Regular vs no/rare exercise
Fatal/nonfatal CHD 0.84 (0.71–1.00)
Fatal/nonfatal CVD 0.86 (0.74–0.99)
Fatal CVD 0.66 (0.46–0.95)
All-cause mortality 0.71 (0.58–0.87)

*Adjusted for age, gender, diabetes duration, type of hypoglycemic treatment, smoking, body-mass index, systolic blood pressure, HbA1c, LDL, HDL, triglycerides, and albuminuria

Investigators also looked at diabetics who reported doing little or no physical activity at baseline but who managed to increase their regular exercise to at least three times per week by the end of the study period (a mean of 4.8 years).

Here the reduction in study end points was even more striking, with the number of cardiovascular deaths among diabetics who increased their exercise levels dropping by 67% as compared with subjects who did not improve their exercise habits. Rates of all-cause mortality, likewise, were reduced by almost the same degree.

Hazard Ratios (95% CI) for Adverse Events According to Exercise Levels*

End point Persistent low exercise vs increasing exercise over study
Fatal/nonfatal CHD 0.41 (0.30–0.54)
Fatal/nonfatal CVD 0.79 (0.69–0.92)
Fatal CVD 0.32 (0.17–0.60)
All-cause mortality 0.35 (0.25–0.49)

*Adjusted for age, gender, diabetes duration, type of hypoglycemic treatment, smoking, body-mass index, systolic blood pressure, HbA1c, LDL, HDL, triglycerides, and albuminuria

Similar reductions were seen when the "increasing-exercise" group was combined with the "regular-exercise" group.

The Swedish findings echo those of a recent German study and meta-analysis, conducted in a mixed cohort of people with type 1 and 2 diabetes. A strength of this latest study, Zethelius stressed, is the extent to which it took conventional cardiovascular risk factors into account.

A Prescription for Exercise

The data is epidemiological, not interventional, so it's not clear whether the same results would be seen in practice, but the reductions are nevertheless "impressive," Zethelius said.

Exercise interventions are typically considered to be even harder in diabetic patients than in the general CV-prevention population, but Zethelius points out that approximately 1800 patients, or one in five, moved from a low physical-activity category into a higher physical-activity bracket over the course of the study.

As to whether it is physicians failing to recommend physical activity in their patients, Zethelius believes this is "more of a culture question. . . . I'm just speculating, but I think that may be different in different countries."

Speaking with heartwire , session moderator Dr Nick Wareham (Institute of Metabolic Science, Cambridge, UK) stressed that the data should serve as a wake-up call to physicians. "These data should encourage us to focus on encouraging physical activity as part and parcel of medical care. Not only are there benefits potentially in terms of cardiovascular risk, but also for other end points such as all-cause mortality and cancer."

Randomized clinical trials looking at hard cardiovascular end points in diabetes patients "are probably never going to be done," Wareham noted. "We do have to rely on this sort of observational data, but it does encourage us to put promotion of physical activity as central to our care. Just the very fact of making people aware of just how little they're doing, that's one thing. If you provide a pedometer to patients and encourage them to measure and be aware of their own inactivity, that's been shown to increase activity. We need to use as many tactics as we can."