Answers to common questions
- High cholesterol and diabetes related to lifestyle habits
- Benefits of taking a statin outweigh risks
- Decision on strength of drugs made on individual basis
Are cholesterol-lowering drugs and diabetes linked?
Statins—the main class of drug used to reduce levels of cholesterol in the blood—have been heavily prescribed for some time. In fact, Simvastatin, the first commercial drug in the family, dates back to the 1980s.
Currently, six to seven million people in the UK are taking it or another similar drug in the same family.
As a result of numerous articles in the UK press over recent months, many people have been surprised to learn that conclusive evidence has emerged that statins increase the risk of maturity onset diabetes in people who take them.
Why has it taken so long for this connection to emerge?
Principally, it is because the increase in risk of developing diabetes is very small, and thus cannot be detected without collecting a lot of data.
Even clinical trials that include thousands of participants have failed to pick up a significant difference between diabetes rates in patients on statins and those on placebos.
However, it is possible to improve detection of more subtle differences between different groups through meta-analysis, when data from multiple studies is pooled and re-checked.
How much does the risk increase?
A meta-analysis published in 2010 in The Lancet, a leading British general medical journal, examined data from over 90,000 people.
The study shows that, over a period of four years, for every 255 people treated with a statin, one extra case of diabetes would result. Overall, the total increase in blood sugar is probably in the order of about 3%.
However, it is important to be clear that most cases of diabetes diagnosed in these study groups would have occurred with or without the individual concerned taking a statin.
Does this mean people taking statins should stop?
Almost certainly not. The same study shows that for each extra case of diabetes caused, 5.4 cardiovascular events (heart attacks or similar occurrences) were prevented. So, the benefits of taking a statin clearly outweigh the risk.
Numerous clinical trials have shown that, in appropriately targeted patients, treatment with a statin cuts the risk of heart disease without simultaneously raising the risk of death from other factors. Rather, it reduces the overall risk of death from all causes.
An even larger pool of data analysed by a Canadian group was published in peer-reviewed British medical journal The BMJ earlier this year.
The study shows that treatment with higher doses of stronger statins carries an increased risk of progression to diabetes. However, this does not mean that everyone should be treated with a weaker statin or at a lower dose.
People who have very high cholesterol or carry a high risk of heart disease are likely to need a higher dose of statin if the treatment is to be effective, regardless of the increased risk of diabetes.
The decision on the strength of treatment has to be made on an individual basis. Accordingly, you simply need to make sure that your doctor is factoring in all considerations when he or she decides what to prescribe you.
Even if a diabetic person stops taking a statin it is unlikely to lower blood sugar to normal levels. However, the action would definitely increase the risk of heart problems in the future.
What can I do to avoid high cholesterol in the first place?
It is worth remembering that both high cholesterol and maturity onset diabetes are clearly related to lifestyle.
For most of us, staying at a healthy weight, keeping active and eating a healthy diet are the best ways to guard against this type of dilemma.