More people should be taking statins for primary prevention, US study suggests
Research shows that prescribing statins for patients with a 7.5% ten-year risk of cardiovascular disease is cost effective for US patients and the threshold could be lowered even further.
US guidelines that set the threshold for starting statin therapy at a lower level than the threshold recommended by the National Institute for Health and Care Excellence (NICE) in England are cost effective, suggests a paper published in JAMA on 14 July 2015.
In 2014, NICE halved the threshold at which statins should be considered for primary prevention — from a 20% risk of experiencing a cardiovascular event in the next ten years to a 10% risk. The decision was criticised by many senior clinicians who were concerned about the risk of side effects.
The United States has a lower recommended threshold for initiating statins. The 2013 American College of Cardiology/American Heart Association (ACC/AHA) cholesterol guidelines recommend statins as primary prevention for patients aged 40–75 years if they have a low density lipoprotein (LDL) cholesterol level of 70mg/dL to 189mg/dL and an estimated ten-year risk of cardiovascular disease of 7.5% or higher. Publication of these guidelines was controversial in the United States as it was a departure from previous recommendations, de-emphasizing low density lipoprotein (LDL) cholesterol thresholds and focusing on total atherosclerotic cardiovascular disease (ASCVD) risk instead.
The paper concludes that the 7.5% threshold is cost effective for US patients and suggests that it might be cost effective to lower the threshold even further.
Researchers modelled scenarios using data from a representative US population aged 40–75 years to determine the cost effectiveness of initiating statin treatment at different thresholds of ten-year cardiovascular risk. They estimated that at the current 7.5% threshold, 48% of adults would be treated with statins, and that this would be associated with an incremental cost-effectiveness ratio (ICER) of US$37,000/QALY (quality-adjusted life-year) compared with a threshold of 10% or higher. Lower thresholds of 4.0% or higher and 3.0% or higher would result in 61% and 67% of adults being treated, respectively, and would be associated with ICERs of US$81,000/QALY and US$140,000/QALY, respectively.
Writing in an accompanying editorial, Philip Greenland, from the department of medicine and preventive medicine at Northwestern University, Chicago, and Michael Lauer, from the division of cardiovascular sciences at the National Heart, Lung, and Blood Institute in Bethesda, Maryland, say: “These findings suggest that the currently recommended threshold of 7.5% is cost effective, and a lower threshold might also be cost-effective.”
Although a ten-year risk threshold of 7.5% or higher may appear to be a low threshold, most cardiovascular events occur among low-risk members of the population, they say.
Another paper in the same issue of JAMA sought to determine whether the 2013 ACC/AHA guidelines improved identification of individuals who developed incident ASCVD or had evidence of coronary artery calcium, compared with the National Cholesterol Education Program’s 2004 ‘Updated third report of the expert panel on detection, evaluation and treatment of high blood cholesterol in adults (ATP III)’ guidelines. A total of 2,435 statin-naive people underwent computed tomography between 2002 and 2005 to detect coronary artery calcification (CAC) and were followed up for a median of 9.4 years for incident CVD. Far more of them were eligible for statins under the ACC/AHA guidelines than the ATPIII guidelines (39% versus 14%). The additional statin-eligible people were at markedly increased risk for experiencing clinical events and to have elevated levels of coronary calcium. Patients eligible for statins under ACC/AHA had increased hazard ratios for incident CVD compared with those eligible by ATP III: 6.8 (95% confidence interval [CI] 3.8-11.9, P<.001) versus 3.1 (95% CI 1.9-5.0, P<.001).
The Royal College of Physicians and Royal College of General Practitioners both declined to comment on the findings and would not be drawn on whether the threshold for initiating statins in the UK should be reviewed. They are awaiting the findings of a review on the safety of statins being conducted by the Medicines and Healthcare products Regulatory Agency (MHRA).
The MHRA review, which is due to be published in the next few months, will examine safety data from clinical trials, observational studies and spontaneous data to ensure that prescribing information on the adverse effects of statins is consistent with these data.
Citation: The Pharmaceutical Journal DOI: 10.1211/PJ.2015.20069031
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