When Should Diabetics Start a Heart Protection Program?

Summarized by Robert W. Griffith, MD
October 23, 2006

Summary

Diabetics are likely to become at high risk of heart attack, stroke, or death about 15 years earlier than persons without diabetes.

Introduction

The author of a recent Canadian study published in the medical journal Lancet was quoted as saying: "A 48-year-old man with diabetes has a 1 in 5 chance of having a heart attack before he's 58. And a 54-year-old woman has a 1 in 5 chance of a heart attack before she retires". Younger diabetics are, of course, at a lower risk. The study was designed to try to establish at what age a diabetic should embark on a cardiovascular-pretective regime. This article summarizes the main points.

What was done

In 1994 the Registered Persons Database in Ontario was used to identify all residents over 20 covered by the Ontario Health Insurance Plan. Those with and without diabetes were identified, and formed the two groups of the study database: 379,003 with diabetes, and 9,018,082 without diabetes.

All participants were followed for 6 years, with a record kept of cadiovascular events - acute myocardial infarction (MI) and stroke - and deaths. In addition, anyone with an MI in the 3 years preceding the baseline were labeled as "recent MI".

The incidences of MI, stroke, and death from any cause were examined for each age group and gender. The definition Low Risk was applied to less than 10 events per 1000 person-years, Moderate Risk for 10 to 19 events per 1000 person-years, and High Risk to 20 or more events per 1000 person-years. (These definitions correspond to those established for the Framingham risk algorithm.)

The ages at which the risk levels crossed into Moderate Risk or High Risk were calculated, and compared for the different groups in both sexes.

What was found

In both diabetics and non-diabetics, the rate of MI increased with age. The average ages of transitions into Moderate Risk and High Risk categories are shown in the table below:

*Note: all-cause death risk was combined with MI in these analyses, as all specific causes of death could not be obtained from the records.

It can be seen that, for men, those with diabetes enter the High Risk category for a heart attack or sudden death at an average age of 48, compared with 61.5 for non-diabetic men. For women the corresponding figures are 54 and 67.5 years, respectively. Using the greater risk of cardiovascular disease (i.e. MI, stroke, and death risks), transition to High Risk occurs ate earlier ages still - 41 for men and 48 for women.

The differences in age for transitions is roughly 15 years; i.e. diabetics are likely to experience the onset of Moderate Risk and High Risk for MI, stroke, or death about 15 years earlier than those without diabetes. Put another way, diabetes confers an equivalent risk to aging of 15 years.

What this means

This careful study clearly shows that the risk of heart disease increased with age in both diabetics and non-diabetics, but for those with diabetes the transition from moderate to high risk occurred at about 15 years earlier than in non-diabetics.

Unfortunately, type 1 and type 2 diabetics weren't analyzed separately. Nevertheless, the findings must surely apply to both groups, assuming blood glucose control is less than optimal.

The conclusions to be drawn are clear. Young folk should avoid diabetes as far as possible, by adapting appropriately healthy lifestyles. And for those with diabetes - type 1 or type 2 - aggressive cardiovascular risk reduction should start well before they reach 40. Such steps should narrow the present disadvantageous gap between cardiovascular risk factors for diabetics.

Source

• Relation between age and cardiovascular disease in men and women with diabetes compared with non-diabetic people: a population-based retrospective cohort study. GL. Booth, MK. Kapral , K. Fung , JV. Tu, Lancet, 2006, vol. 368, pp. 29--36

Related Links
Patient Care: Diabetes and Atherosclerosis, the Deadly Duo
WebMD: Diabetes, Stroke
The Prevalence and Cost of Diabetes