According to the large scale reports in The Lancet, the harms of statins have been largely over-estimated because of misinterpretation of research outcomes, and the advantages of the cholesterol-lowering medicines have been underrated.
The authors of the review – which includes Prof. Liam Smeeth, hope their results will assist patients and physicians make informed choices about the use of statin therapy.
Statins are a commonly used class of prescription medicines that decrease levels of bad low-density lipoprotein (LDL) cholesterol.
Raised LDL cholesterol is a major risk factor for cardiovascular diseases, like as heart attack and stroke, and statins decrease it by reducing down the production of cholesterol in the liver.
With respect to data from the National Health and Nutrition Examination Survey, utilization of cholesterol lowering medicines in the United States enhanced from 18 % to 26 % between 2003-2012, with 93 % of these drugs being statins.
While many researches have hailed the heart health advantages of statin use, others have increased issues about the safety of statin treatment, with some investigators claiming the medicines do more harm than good.
For their review, Prof. Smeeth and peers carried out an comprehensive analysis of various studies that have examined results in sufferers obtaining statin therapy, with a view to gaining a better comprehension of the advantages and risks the drugs may pose.
Evaluating the reliability of various trial methods
The study team viewed the strengths and limitations of a wide range of research, which includes randomized controlled trials (RCTs), meta-analyses, and observational studies.
In RCTs, the results of a specific drug are compared with a placebo in one or more groups of sufferers.
These trials are best for identifying cause and effect of a drug, the investigators note; random allocation of sufferers to the therapy or placebo groups means investigators are better capable of attributing health outcomes to the drug, while “blinding” sufferers and investigators to what drug each individual is taking decreases bias.
Meta-analyses gather and evaluate proof from a number of RCTs that have examined the results of the same drug, which Prof. Smeeth and team say can increase the reliability and generalizability of the results.
With respect to the review authors, observational studies are most likely the least reliable for identifying the effects of drug therapies.
Observational studies look at the health results of sufferers who have been given a drug as part of their standard care and evaluate them with individuals who have not been given the treatment.
However, the research team notices that because physicians are likely to have given a medicine to an individual for a reason, their health is probably to be different to those not getting the drug, which may influence the outcomes.
What is more, the authors indicate that sufferers administered a drug in regular care to know they are being treated with it and are conscious of what the side effects are. As a result, they are more probably to attribute any side effects to the medicine, while individuals not getting the drug are less probably to do so.
Statin therapy decreases risk of cardiovascular events by 25 %
Prof. Smeeth and peers took all of these aspects into consideration when evaluating studies that viewed at the health results of sufferers treated with statin therapy.
By looking at huge RCTs, the investigators identified that every one millimole per liter decrease in LDL cholesterol reduced the risk of ischemic stroke, heart attack, heart associated deaths, and coronary artery bypass surgery by about 25 % each year. Statin therapy was used, following the first year of therapy.
Looking at the outcomes of meta-analyses, the investigators identified that the risk of heart-related events was even more reduced with larger LDL cholesterol reductions as an outcome of statin therapy.
As an example, the study team identified proof to recommend that a 2 millimole per liter decrease in LDL cholesterol with statin therapy – 40 milligrams of atorvastatin daily – is connected with a nearly 50 percent decrease in the risk of a major cardiovascular event.
While some observational research have connected statin use with reduced risk of cancer, respiratory problems, and other medical issues, the authors say there was no proof from RCTs that these consequences are a direct outcome of statin therapy.
Enhanced risks of ischemic stroke, diabetes, and myopathy with statin use.
Myopathy – a condition characterized by muscle weakness – is one problem that emerged as being directly triggered by statin use in both observational studies and RCTs, the authors report.
However, they identified that the risk of developing this problem is minimal, with one extra case coming up for every 10,000 individuals treated with statin therapy every year.
RCTs did demonstrate an enhanced risk of diabetes with statin treatment, say the authors, with about 10-20 extra cases coming up in every 10,000 patients yearly. However, the investigators observe that these cases were most probably to take place in sufferers currently at enhanced risk of diabetes.
Observational studies determined a connection between statin therapy and enhanced risk of hemorrhagic stroke, the study team says, and RCTs recommend that statin use may raise this risk by about 20 %.
Extrapolating this to Western populations, the investigators approximate that statin treatment may result in an extra 10-20 cases of hemorrhagic stroke per 10,000 sufferers every year. However, the team notices that decrease in ischemic stroke risk with statin treatment is considerably larger than the enhanced risk of hemorrhagic stroke, so the risk of stroke overall is decreased with statin use.
While observational studies have revealed that statin therapy raises the risk of muscle pain and weakness, creating a “statin intolerance,” the authors say this impact is not likely to be a direct outcome of statins themselves.
From RCTs, the research team identified that about 10-20 cases of adverse side effects – which includes muscle pain and weakness – per 10,000 sufferers could be linked to statin therapy every year.
Ultimately, the investigators found no proof from RCTs that statins directly lead to other side effects claimed in observational studies, which includes aggression, cataracts, kidney injury, liver disease, memory loss and sleep problems.