Statins, also known as HMG-CoA reductase inhibitors, (which abbreviates a big chemical name) work by blocking this enzyme that is part of the body’s way of producing cholesterol. But they may do other good things.
Lovastatin (Merck’s Mevacor) was the first statin discovered as a naturally occurring compound found in oyster mushrooms and then extracted in the 1970’s. Oyster mushrooms grow on dying trees all over the world and are a delicacy in East Asian cuisine. But I digress.
Statins are already among the most widely prescribed drugs. Around 12% of US Americans are already taking them. They are cheap and safe and definitely save the lives of people who have already had a heart attack – secondary prevention – and people who have high levels of low density lipoprotein (LDL) cholesterol – primary prevention. There is evidence that statins might prevent or treat lots of other things and maybe everybody’s LDL levels should be lower. Maybe having LDL cholesterol levels that are too low is like being too rich.
To study the first question, whether everybody should be taking statins to prevent non-cardiovascular diseases, egg heads from University of Edinburgh reviewed the evidence in a report in Annals of Internal Medicine.(1) They did a meta-analysis of meta-analyses that included 278 unique non-CVD outcomes studies. In the case of many types of cancer, chronic obstructive pulmonary disease (COPD), dementia, pancreatitis, and others—they found no convincing evidence that statins improved final outcomes in these conditions.
They did however find pretty significant but not conclusive evidence that statins decreased cancer mortality in patients who were already taking them prior to cancer diagnosis. “Clinical guidelines currently do not indicate the use of statins to improve cancer prognosis; however, our results are encouraging enough to merit further investigation,” the authors wrote. Statins were linked to fewer exacerbations of COPD. Exacerbations means winding up in the doctor’s office because of worsening symptoms. This isn’t a surprise because some evidence shows that statins have potential antiviral and anti-inflammatory effects, and respiratory viral infections are a major cause of COPD exacerbation. Also randomized clinical trials showed statins were associated with decreased all-cause mortality in patients with chronic kidney disease (CKD), which supports prescribing statins for these patients to reduce their long-term death risk. Finally, there was “suggestive” evidence of statin use and lower risks for Alzheimer’s disease, dementia, kidney injury, and infection.
It might be for all of these things that these ancillary benefits of statins were not primary. Instead they were just because they prevented cardiovascular disease (CVD) and that secondarily helped some cancer, COPD or kidney disease. For example the trial data also showed that cardiovascular-related deaths accounted for more than 40% of all deaths in patients with CKD and heart disease makes COPD worse of course.
As far as the potential harms from statins, such as induced diabetes and muscle disease, “the evidence had a relatively low level of credibility,” they wrote, so that doesn’t justify withholding statins out of concern for these potential harms.
However this review still doesn’t support making any changes to the current clinical recommendations for using statins for non-CVD conditions, the researchers concluded.
That doesn’t answer the second question. Should we all be taking statins to prevent CVD? How low can your LDL cholesterol go? Lots of people have heart attacks without LDL cholesterol levels in the range that current recommendations call for starting a statin. Why did God make LDL cholesterol? Would it kill you if your LDL cholesterol was zero?
I’m not taking a statin yet. Maybe next Thursday, though. We’ll see.
1. He Y et al. Statins and Multiple Noncardiovascular Outcomes: Umbrella Review of Meta-analyses of Observational Studies and Randomized Controlled Trials. Published: Ann Intern Med. 2018;169(8):543-553. DOI: 10.7326/M18-0808. Published at www.annals.org on 9 October 2018
2. John Murphy, MDLinx | November 16, 2018. https://www.mdlinx.com/internal-medicine/article/2984?utm_source=in-house&utm_medium=message&utm_campaign=itn-statins-nov18