November 4, 2009

Veterans with Moderate CAC Scores DO prevent Heart Attack with Aggressive BG Lowering

A study just published in Diabetes takes a closer look at the notorious Veterans Study. I have blogged before about that study here:

Why Doctors Are Telling Type 2s Not to Lower Blood Sugar And Why They Are Wrong.

The veterans study is one of two studies that found that aggressive blood sugar control did not appear to make any difference in the likelihood of having a heart attack.

But this new analysis of data from the veteran's study found that aggressive lowering of blood sugar did have a dramatic effect on the likelihood of having a heart attack, but only in people who did not already have evidence of severely hardened arteries as measured by CAC heart scans.

The abstract of the new study can be read here.

Intensive Glucose-Lowering Therapy Reduces Cardiovascular Disease Events in Veterans Affairs Diabetes Trial Participants With Lower Calcified Coronary Atherosclerosis Peter D. Reaven et al. Diabetes, November 2009 vol. 58 no. 11 2642-2648. doi: 10.2337/db09-0618

In this study, a subset of the subjects in the veteran's study, 301 type 2 patients, had their degree of artery thickening measured by heart scans, i.e. the coronary artery calcium (CAC) computed tomography test. Participants were then followed over the 7.5-year study for development of cardiovascular end points.

After subjecting their data to an oddball statistical manipulations I won't pretend to understand and hence cannot entirely trust, the researchers came up with the finding that there appears to be a Rubicon of sorts with these heart scan scores.

If patients started the study with CAC scores below 100, aggressive lowering of their blood sugar yielded impressive lowering of their rate of cardiovascular "events." But if they started out with CAC scan values above 100 then aggressively lowering their blood sugar did not change the risk of heart attack.

The actual numbers reported were these:
Among those randomized to intensive treatment, for the subgroup with CAC >100, 11 of 62 individuals had events, while only 1 of 52 individuals with CAC ≤100 had an event.
This suggests that there is a point after which you have permanently damaged your cardiovascular system and that past that point, controlling blood sugar alone won't undo the damage. This makes sense because the CAC scan reports on the amount of calcium deposited in your arteries in the form of plaque, and after you've calcified your arteries past a certain point, they are likely to stay that way.

But if that is your situation, all is not lost. Dr. Davis over at the Heart Scan Blog claims that his patients have improved their CAC scores using interventions that include high dose Vitamin D3, lots of fish oil, Niacin, and cutting out wheat from their diets.

Why fish oil may be so helpful was illuminated by a recently reported study where researchers analyzed plaques removed from people having carotid endarterectomy--the operation where they ream out people's carotid arteries to remove plaques that are preventing blood from getting to their brains.

The researchers report:
All of the fats in the plaques were assessed with mass spectrometry... The plaques of asymptomatic patients [i.e. those having no signs that their brain functions was impaired because of clogged arteries] contained more than twice as much DHA as the symptomatic patients, and about one and a half times as much EPA. Significantly less inflammation was also seen in the carotid atherosclerotic plaques from asymptomatic patients.

You can read more about that study here:

Science News: Fish Oil May Protect Against Stroke From Ruptured Carotid Artery Plaques

Getting back to the veterans study. It is worth remembering that the subjects in the veterans study were mostly elderly people whose blood sugar had been way out of control for many years. If you are recently diagnosed, chances are you have not built up insurmountable levels of plaque in your blood vessels. And if that is true, then lowering your blood sugar aggressively may help prevent heart attack.

It is also worth mentioning that even in studies where aggressive lowering of blood sugar did not prevent heart attack, it did lower the incidence of kidney failure. This alone should make it worth pursuing.

And of course, many of us also have found that lowering our blood sugars very aggressively can prevent or reverse neuropathy.

If your doctor was one who warned you against the "dangers" of lowering blood sugar, make sure to tell your doctor about this latest study--and print out the abstract and take it along. Let the doctor know that one of the major studies being cited as arguing against tight control actually showed aggressive blood sugar lowering caused a dramatic drop in heart attacks in people whose CAC scores were modest when they began the blood sugar lowering.



Anonymous said...

Hi Jenny,

I've been reading your blog for a few weeks now and I appreciate it. I recall this study when it was first reported and I recall my reaction at that time: of course "tight control" is counter-productive! I'm sure that their definition of tight control was not via a low-carb diet, which would minimize the insulin response. Instead, I'm sure it was the AHA, ADA dogma of eating a "balanced" (high carb) diet and slamming in a little extra insulin. That would only exacerbate the insulin resistance and accelerate all the associated problems. The new information you are reporting only confirms this.
Cincinnati, OH

Anonymous said...

Just goes to show you can "prove" wehatever you are paid to prove using statistics. This makes a lot more sense than the original paper.

Would be interesting to see the lipids involved also.

As well as increasing Omega 3s it makes sense to reduce Omega 6s when you look at statistics such as Stephan graphs here