In this new study done in Japan, 275 people admitted with a heart attack were evaluated for diabetes and pre-diabetes. They were evaluated 14 days after the heart attack, and people who had significant complications in hospital were excluded.
Strikingly, of the 275 consecutive patients with AMI (acute heart attack) they evaluated, only 78 had normal glucose tolerance (only 28%).
There were 85 who were classed in the “diabetes” group, either because they had already been diagnosed before their heart attack or because they had persistent fasting blood sugar in the diabetic range (above 125 mg/dl). The other 112 showed abnormal glucose tolerance when they were tested just prior to discharge from the hospital, either in the diabetic or pre-diabetic range. Thus, the “AGT” group included people who did NOT meet diagnostic criteria for diabetes based on fasting glucose levels, but did meet criteria for either pre-diabetes or diabetes due to the degree of rise in their blood glucose after drinking 75 grams of glucose. (at least 140 mg/dl at 2 hours)
For the AGT group:
- they had a worse outcome on follow-up than the people without abnormal glucose tolerance. In fact, their outcome was just as bad as for the people classed in the “diabetes” group (“an equivalent prognosis to the DM group“)
Refered to as a “Hazard Ratio” (HR), they were looking at the risk for “a major cardiovascular event” (you don’t want one of those). Those people with abnormal glucose tolerance had 2.65 times as much Hazard Ratio as those with normal glucose tolerance, which was not statistically different from the people with diabetes, who had 3.27 times as much HR as those with normal glucose tolerance. (Impaired glucose tolerance is about glucose rising after meals.)
- Having an elevated fasting blood glucose (under 126 mg/dl) was not found to be associated with a worse outcome during the follow-up period (however, the result found suggest that a study with a larger number of subjects might show something different).
The study was not large. If a study with more people were done, it might show a bit more gradation between the outcomes for the different groups.
Take Home Message: Again, know how high your blood glucose rises after meals
LINK to the full text of the research study
Newly diagnosed glucose intolerance and prognosis after acute myocardial infarction: comparison of post-challenge versus fasting glucose concentrations.
Department of Cardiovascular Medicine, Nishinomiya Watanabe Cardiovascular Center, 3-25 Ikeda-cho, Nishinomiya City 662-0911, Japan; email@example.com.
Recent studies have demonstrated that newly diagnosed glucose intolerance is common among patients with acute myocardial infarction (AMI). The purpose of this study was to assess the long-term clinical cardiovascular outcomes in participants with AMI with abnormal fasting glucose compared with normal fasting glucose and an abnormal oral glucose tolerance test (OGTT) compared with a normal OGTT.
A prospective study was performed in 275 consecutive patients with AMI, 85 of whom had pre-diagnosed diabetes mellitus (DM). Those without DM were divided into two groups based on the 75 g OGTT at the time of discharge. Abnormal glucose tolerance (AGT) was defined as 2 h glucose ≥140 mg/dl; 78 patients had normal glucose tolerance (NGT) and 112 had AGT. The same patients were also reclassified into the normal fasting glucose group (NFG; n=168) or the impaired fasting glucose group (IFG; n=22). The association between the glucometabolic status and long-term major adverse cardiovascular event rates was evaluated.
Kaplan-Meier survival curves showed that the AGT group had a worse prognosis than the NGT group and an equivalent prognosis to the DM group (p<0.0005). Cox proportional hazard model analysis showed that the HR of AGT to NGT for major adverse cardiovascular event rates was 2.65 (95% CI 1.37 to 5.15, p=0.004) while the HR of DM to NGT was 3.27 (1.68 to 6.38, p=0.0005). However, Cox HR of IFG to NFG for major adverse cardiovascular event rates was 1.83 (0.86 to 3.87), which was not significant.
In patients with AMI, an abnormal OGTT is a better risk factor for future adverse cardiovascular events than impaired fasting blood glucose.
PMID: 22581733 (added emphasis mine)
In this study, it is the rise in blood glucose after meals that is associated with bad outcomes, not the fasting levels.