AIM-HIGH Hits Low & Misses Target

Thanks to Dr. Peter G for pointing this out to me.  Last Thursday, the National Institutes of Health and its National Heart, Lung & Blood Institute announced the premature stoppage (18 months early) of its Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health (AIM-HIGH), aimed at studying the effect of 2,000mg daily of Niaspan brand of niacin in those patients with optimized LDL cholesterol (40-80mg/dL) on simvastatin +/- ezetimibe.  The 3,414 participants followed for 32 months were 64yo on average w/most also having diabetes, heart disease & hypertension.

Several thoughts came to mind as I read over the scarce information available in their press release.  First, don't assume anything.  As we were taught in medical school, assumptions make an a-- out of you and me (if you don't get this, look carefully at the spelling of assume).  So while heart attack risk has been inversely correlated to HDL in those w/optimized LDL, there have been no studies demonstrating any benefit from purposefully raising HDL.  Again, we only have observational data but nothing causative.

Second, just because it didn't work in this instance doesn't mean it won't work in another.  Now, I'm sure that will be the spin from Big Pharma.  But in fact, we've had to learn the hard way from studies like Women's Health Initiative and others that what's good for one specific group can't always be generalized to the public.  So perhaps, using niacin to raise HDL doesn't work in those w/pre-existing disease but might work in those without.

Third, perhaps they didn't raise HDL enough.  But that's pure speculation & BS on my part.  The press release reported that HDL was raised 22% on average but it didn't mention baseline HDL.  This was just a press release and, as such, has not been published in a peer-reviewed journal.  However, with a bit of sleuthing, I was able to find a description of the trial which noted inclusion criteria if HDL <40mg/dL in men & <50mg/dL in women.  With observational data, we tend to consider HDL normal when it is 40-59mg/dL, which implies average risk of heart disease; HDL is considered cardioprotective when >60mg/dL so perhaps we shouldn't have expected any benefit since HDL would only have increased from 39mg/dL to 47mg/dL at best.  Only time will tell when the complete data is published.

So what are we to do at this point?  Especially considering a slight increase in ischemic stroke . . . As always, do your research and have an in-depth conversation with your family physician so that you can make a decision that is best for your individual situation.