A US study has linked the cholesterol-lowering drug statin to a heightened risk of type 2 diabetes among patients already deemed to be at high risk of the condition.
Published in the journal BMJ Open Diabetes Research and Care, the study looked at data from 3,234 overweight or obese participants taking part in the US Diabetes Prevention Programme Outcomes Study.
After 10 years follow-up, a third of patients had started using statins. Researchers found that taking the drugs was associated with a 36% heightened risk of being diagnosed with type 2 diabetes, compared to those who had not been prescribed.
"This study indicates that statins can increase the onset of diabetes in some people,” said Professor Jeremy Pearson, associate medical director at the British Heart Foundation.
"However, it does not mean that people should stop taking their statins as there is no doubt they save lives. Instead, the findings reinforce the need to regularly monitor the blood sugar levels of patients taking statins."
In a separate study, British researchers found a “significant” number of patients prescribed statins only had a small chance of developing cardiovascular disease (CVD)
The report, published in the British Journal of General Practice, found a "significant over-treatment" of statin therapy with patients who had less than 10% chance of having a heart attack or stroke within 10 years.
Tracking statin prescribing between 2000 and 2015, researchers from the University of Birmingham looked at 1.4 million patients aged over 40 across 248 GP practices across England and Wales.
Some 217,860 patients started statin treatment during this time, with 151,788 recorded as having undergone the recommended risk assessment for CVD.
The National Institute for Health and Care Excellence recommends anyone with a 10% chance of developing CVD should be offered statin. However, the study revealed many patients offered the treatment had a low risk of CVD.
Statin initiations increased from 2000 to 2006, after which the rate dropped to almost half by 2015. The CVD risk assessment was introduced in 2012. However, only 27.1% of patients have had their risk score recorded since then.
One in six patients who had the risk assessment and went on to start statin therapy were in the low-risk category, the researchers found.
However, the study notes that clinicians may have been "responding to individual patient preference when prescribing to low-risk patients." The researchers also found potential "under-treatment" among those deemed to be at high risk - to have a 20% or higher chance of CVD within a decade.
Among those that had a risk score recorded after it was introduced in 2012, just over a third (35%) of high-risk patients were prescribed statins.
"It is not possible to establish whether those patients who were above the threshold to be prescribed a statin did not receive treatment because they were not offered it or because they declined an offer," the authors said.
"This study confirms that there is potential under-treatment of patients at high risk of cardiovascular disease (CVD) and, although only a small proportion of low-risk patients are initiated on statins, low-risk patients represent a significant proportion of all statin initiations."
Commenting on the study, Professor Helen Stokes-Lampard, chairman of the Royal College of GPs, said: "Patients should be reassured that GPs are highly-trained to prescribe statins and base their decisions on the circumstances of the individual patient sitting in front of them, including physical, physiological and social factors that might be affecting their health.
"This study is interesting because it looks at possible overtreatment and undertreatment, but it simplifies the true situation because it does not include any information about individual patient preferences, other health conditions, or data that was not accurately coded in patient records.
"This study emphasises the importance of calculating an accurate risk score which can then help healthcare professionals have an honest discussion with their patients about the benefits and risks which are unique to them."