Wednesday, February 17, 2010

Statins Don't Cause Diabetes

As of this morning, the only major source reporting the results of a recent study from Lancet is Business Week. However, the headlines that will likely pop up in the next few hours will likely be similar to theirs: "Cholesterol-Cutting Drugs Raise Diabetes Risk by 9% in Study." In my last post I discussed how the media likes bad news stories, so even though this is not yet all over the headlines, I will take a preemptive strike for potentially concerned patients.
The Lancet study is a large major meta-analysis of major statin trials, looking to see if there is a risk associated with statins and the development of diabetes.

The authors likely got the idea to do a meta-analysis from the JUPITER trial which showed that Crestor reduced heart attacks in patients who wouldn't have generally gotten a statin, except they had an elevated CRP (see Crestor: Get Ready to Ask Your Doctor for the CRP Test. ) One thing seen in this study was a potential increased risk of the development of diabetes. I mentioned this in my blog post when the data was first released that physician report of diabetes was increased in the Crestor group (270 reports of diabetes, vs. 216 in the placebo group; P=0.01). I stated that though one might be concerned about this, these were physician reports without confirmation. When looking at the study lab values in Jupiter, there were no significant differences with respect to the fasting blood glucose level, and the A1c level was pretty much the same (5.9% and 5.8%). I also mentioned that there was no biologically plausible reason to suspect Crestor, or any statin, as a cause of diabetes. In addition, both groups of patients in the JUPITER study had a 41% prevalence of metabolic syndrome, which is a pre-diabetic state. Therefore it should not have been surprising to find an increase in diabetes in both groups.

The meta-analysis looked at Jupiter and several other studies combined and found a 9% increase in the development of diabetes in patients taking statins.
So if this is true, how can you say that statins don't cause diabetes????
1. The 9% value is a relative risk, not an absolute risk. If 1/100 patients taking placebo have a side effect, and 2/100 patients taking a statin have a side effect, the relative risk increase is a doubling or 100%, but the real or absolute risk is only 1%. Drug companies and the media (and unfortunately some authors, as was the case in this study) like to talk about relative risk instead of absolute risk, because it makes there drug/data/news story look better. In this study, the actual increase in diabetes was 0.38% or about one third of 1%. Even though the result is statistically significant (true by scientific standards), the magnitude of the increase is so small that there is a high possibility that this is not true.
2. The study is a meta-analysis, which by design can not prove causation. The only way to really find this out is to do a large, randomized controlled study to specifically look at whether or not statins cause diabetes. This will never happen because 1) given the low absolute risk, the number of patients needed in this study would be tens to hundreds of thousands, which means the study would be ridiculously expensive and 2) with Lipitor going generic, no drug company is going to fund such a study. I spoke of the dangers of meta-analysis many times, specifically in talking about Nissen's meta-analysis of Avandia (multiple posts on this). Even in Nissen's own meta-analysis showing a "40% increase in heart attacks" in patients taking Avandia (relative risk), there was really NO DIFFERENCE in the absolute risk in his study! Of course that didn't stop the press, and millions of patients stopped taking Avandia. Unlike the randomized, controlled trial for statins and diabetes we will never see, there was a randomized controlled trial on cardiac safety and Avandia called the RECORD trial which was presented at the ADA this past summer. It showed NO RISK of heart attacks with Avandia. Don't be surprised if you never hear about this, since the press does not seem to be too fond of reporting good news.
3. As above, there is no biologic reason to believe that a statin medication would cause diabetes.

In other words, what you are seeing in the headlines is statistical garbage, that really doesn't mean anything. An incredibly low absolute risk found in a meta-analysis without a biologic reason to support a connection between statins and diabetes should not be cause for concern.

12 comments:

Anonymous said...

Thank you for speaking up about an analysis which warrants no further discussion. It was poorly designed and only fueled misconceptions about the statins. Of course, no mention in this 'analysis' was the word relative risk used. One would expect that with all of the PhD involved in the study, someone would have felt the need to inform the author about this. Obviously this was by design and not for a lack of knowledge.

Tonino Michienzi, RPh

Mike Hussey said...

Diabetic retinopathy could be associated with poorer memory and diminished brain power in people with Type 2 diabetes, according to a new research.

Anonymous said...

I have been doing research on this since recently my husband who has been on statins since his heart attack five years ago now has an elevated glucose. We have to now monitor it twice a day.

Does this mean that he is part of the 9%? Is this reversable?

My husband has heart disease and I believe as a result of trying to prevent further heart attacks his medication has now caused him to have a metobolic syndrome. Sometimes it seems the cure is worse than the disease.

Dr. Matthew Mintz said...

there is no need for even a diabetic patient who is not on insulin or a sulfonylurea to monitor blood sugar twice a day.
Basically, statins can push the sugar up a tiny bit in some patients. It will not cause diabetes, but in someone with metabolic syndrome/pre-diabetes, it could "push" them to an official diagnosis of diabetes. The reality is that metabolic syndrome/pre-diabetes is a spectrum. It's not like sugar 125/A1c 6.4 you are healthy and sugar of 126/A1c 6.5 your sick.
Pre-diabetes is reversible, with diet and exercise, as well as medications.

Marcia Egan said...

I'm 53 woman now post menoupausal. been on lipitor 10mg for 5 years. Was put on initally since FBS averaged 95-114. aic 5.4-5.5 Use diet and exercise. Inital cholesterol 207 with ldl 110 hdl in 80's. on lipitor 10 cholesteral 197 and hdl 112 and ldl 74. I'm 5 ft 4 112 pounds and take lisinopril 20 mg od for high BP. Grand father had heart disease.I have normal tryglycerides and work out 5 days a week. should I still take lipitor?

Anonymous said...

I'm 53 woman now post menoupausal. been on lipitor 10mg for 5 years. Was put on initally since FBS averaged 95-114. aic 5.4-5.5 Use diet and exercise. Inital cholesterol 207 with ldl 110 hdl in 80's. on lipitor 10mg cholesteral 197 and hdl 112 and ldl 74. I'm 5 ft 4 112 pounds and take lisinopril 20 mg od for high BP. Family history of type 2 diabetes in grandparents and parents. Grand father had heart disease.I have normal tryglycerides, c reactive protein very low and work out 5 days a week. should I still take lipitor? also eat low carb and very little sugar to try to prevent type 2 diabetes. FBS and A1c have been about the same for last 5 Years. GTT
was normal but after 2 hours of test hypoglycemis with blood suagr of 40. what do you reccomend?
thanks
shoudl I take baby aspirin?

Dr. Matthew Mintz said...

Anonymous/Marcia,
The key is risk of diabetes vs. risk of heart attack. Lipitor may very slightly increase your risk of developing diabetes, but it would likely have more of a substantial effect on preventing a heart attack.
I would strongly recommend using the NIH's risk calculator to figure out your own individual risk. Here's the link:
http://hp2010.nhlbihin.net/atpiii/calculator.asp?usertype=prof
Assuming your blood pressure is controlled on the lisinopril and that you are not a smoker, based on the pre-lipitor numbers you have posted, your risk for heart attack or stroke in the next 10 years is 1%. This is not high, but it is not nothing. It also does not take into account your family history. Your pre-lipitor LDL of 110 (based on the 1% calculation) not be (according to the latest guidelines which will soon be indicated) be high enough to suggest that you need to be on Lipitor. However, this is based on incomplete information, so please go to the web site to check your own numbers and contact your physician before making any changes.

Anonymous said...

thanks for getting back to me. I see my risk of heart attack is 1% back to my cholesterol prior to lipitor. Howeer this doesn't take into account a prediabetes state with abnormal fbs and a1c of 5.5. These are the only metabolic risk factors plus high BP. My md said I'd be type 2 but I watch what I eat and work out. would my prediabetes state make the lipitor more important? If I go off will any impairment in glucose this might have caused return to pre lipitor numbers? If I stop the lipitor how long till my numbers return to what they were without lipitor in my system. Is there any study that supports a woman taking baby aspirin prophylactically? thanks again.

Dr. Matthew Mintz said...

You have impaired fasting glucose, which may in fact go down after stopping the lipitor, and hypertension, so you do not meet the criteria for metabolic syndrome. You have a genetically increased risk for developing diabetes, but without having diabetes or metabolic syndrome, you don't have a clearly increased risk for heart attack or stroke. The best estimate of your risk (even with the HTN, family hx of diabetes, and impaired fasting glucose) is still the NIH calculator.
Aspirin is more controversial. Study just came out today (that I haven't had a chance to read) suggesting benefit may not be that great.

Anonymous said...

thank you for your advice. I'm going off lipitor and I'll check my numbers in a couple of months for cholesterol and fbs an a1c. thanks again

Anonymous said...

Can you offer any tips, suggestions or prescriptions to help heal someone who has ceased taking Lipitor due to muscle pain???

Was on Lipitor for a long time and pains were brought on by taking up running. Had pains all last year and finally found out it could be caused by Lipitor. Stopped taking four weeks ago, but still have pains off and on.
thanks.

Dr. Matthew Mintz said...

In general, muscle pains caused by statins such as Lipitor usually go away when the medication is stopped. The medications do not typically cause permanent damage to muscles. Also, if you were on Lipitor for years, and then recently got muscle pains, the chance that your muscle pains are due to the Lipitor is pretty small, though not impossible.
Thus, I would recommend that you see a physician to determine if there are any other causes of your muscle pains. You would need both an examination as well as blood tests that can look for muscle damage and other causes of muscle pain.