Statins have been targeted less efficiently in patients most at risk of cardiovascular disease since the publication of NICE guidance in 2007, concludes a new UK study.
The researchers – published in Heart this month – said there has been a ‘substantive’ overuse of statins in low-risk groups since NICE guidance was published that the drugs remain underused in high-risk patients.
Their study of data from 3.8m patients in primary care from 1993 to 2011 showed that although rates of statin use among patients at high cardiovascular risk have gone up in recent years, they have also risen considerably among people at low risk.
Before 2007, 7% of patients with a 10-year predicted risk over 20% were prescribed a statin, compared with 30% after 2007. For low-risk patients with less than 15% 10-year predicted risk, the rate of statin prescriptions rose from 2% to 5%.
The findings create an overall picture of statins being increasingly prescribed at lower risk, the authors report. The average five-year observed cardiovascular risk among statin users fell from 17% before to 7% after 2007.
The team also found substantial variation among general practices in statin prescribing rates after 2007, ranging from 2% to 30% among low-risk and from 8% to 62% among high-risk patients.
The paper concluded : ‘There appeared to be a substantive overuse in patients with low CVD risk as well as underuse in those with high CVD risk. The strategy to identify patients at high CVD risk in UK clinical practice has become less efficient following the publication of NICE guidance.’
The researchers also added that ‘approaches in how high cardiovascular disease risk is assessed vary between practices’ and that that three risk scores are currently in use – Framingham, ASSIGN and QRISK2.
The paper’s publication coincides with another paper in the British Journal of General Practice that suggests there is considerable confusion among GPs over which cardiovascular risk score to choose.
Dr Ivan Benett, clinical director for Central Manchester CCG and a GPSI in cardiology, said: ‘I would agree with the conclusions of both papers that there is confusion [over] which scoring method is most appropriate and what levels to intervene at, but mostly that we are undertreating those who stand to gain most.’
Dr Benett added that there is also confusion among clinicians when applying primary and secondary prevention thresholds for intervention, which could at least partly explain why statins are being overprescribed in low-risk groups.
‘Our pathology lab, for example, highlights cholesterol levels above 4 mmol/l as “high”, whether or not they have pre-existing cardiovascular disease. Therefore those in the primary prevention category may be being given statins on this basis.’
But he said that the underuse of statins in high-risk patients is the major concern and that, even more worryingly, patients with established coronary heart disease are not being optimally treated with statins, with QOF data showing around 30% of these patients are not achieving target cholesterol levels.
Dr Christopher Arden, GPSI in cardiology and a GP in Hampshire, said it was important to remember the positive aspect that many more high-risk patients are being captured, however.
He said: ‘The increase in prescribing in high-risk patients – from 7% to 30% – clearly shows that high-risk patients are more often being identified and being put on treatment than 10 to 12 years ago.
‘I’d certainly acknowledge there’s a lot of work to be done in terms of making sure that residual risk in the high-risk is addressed. But we have to remember it’s not just statins – these patients often come with other comorbidities and other lifestyle risk factors that we have to address – the statin prescribing is rather a crude measure.’
Dr Arden nonetheless agreed on the need to improve on current risk prediction methods.
He said: ‘It’s not helped by the degree of confusion over which risk scores to use and we could do with a bit of consistency in education and messaging to GPs.’