Greater CV Protection When Guidelines Back Broader Statin Use

Debra L. Beck

January 16, 2018

A head-to-head comparison of five dyslipidemia management guidelines suggests that those with more conservative recommendations were associated with fewer patients treated and more cardiovascular events that might have been avoidable.[1]

Latest guidelines from the American College of Cardiology/American Heart Association (ACC/AHA), the Canadian Cardiovascular Society (CCS), and the National Institute for Heath and Care Excellence (NICE) in the United Kingdom recommended statin therapy for 40% to 44% of individuals from a contemporary primary care cohort, in the study, published in the January 16 issue of Annals of Internal Medicine.  

In contrast, the European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) guidelines recommended that just 15% of the same cohort be given a statin. The researchers also considered a "statement" on statin use from the US Preventive Services Task Force (USPSTF) and found that with use of the USPSTF criteria, 31% of the primary prevention cohort would have been prescribed a statin.

These more conservative recommendations were not without consequences: Using actual observational data on events and modeling the events based on the various guidelines, they projected that the estimated percentage of atherosclerotic cardiovascular disease (ASCVD) events that could have been prevented by the use of high-intensity statins (assuming a 50% reduction in low-density lipoprotein cholesterol) for 10 years was 34% with the Canadian and US guidelines, 32% with NICE, 27% with USPSTF, and just 13% with ESC/EAS.  

"Guidelines from the ACC/AHA, CCS, or NICE should be followed rather than those from the USPSTF and ESC/EAS," the authors conclude. "If we assume negligible harm from statin therapy and low cost for the drugs, these strategies should prevent many more ASCVD events."

"I think the problem in Europe is that, while the ESC and EAS are very familiar with the science, the ESC has tried to be inclusive and they have allowed many other organizations to participate in the guideline development process," principal investigator, Dr Børge Nordestgaard (University of Copenhagen, Denmark) told theheart.org | Medscape Cardiology.

"This has diluted the scientific quality of the committee and given rise to these more conservative recommendations," he said.

Indeed, the most recent European practice guidelines are authored by "The Sixth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (constituted by representatives of 10 societies and by invited experts)."[2]

Besides the ESC, EAS, European Heart Network, and European Society of Hypertension, the societies include specialists in stroke, diabetes, sports medicine, family medicine, and behavioral medicine.

"Many general practitioners in Europe are still so against the idea of giving medicine to somebody they believe is still healthy," said Nordestgaard. "And some of these voices are being given a say in the European guidelines."

It wouldn't take much to fix the situation, he said. While the other guidelines have all expanded statin indications based on strong clinical trial evidence, the ESC/EAS guidelines continued to recommend a treatment threshold of a 5% 10-year risk for fatal ASCVD.

"That corresponds to a roughly 20% morbidity risk of CVD, where the US guidelines cut it down to 7.5% and the Canadians did similarly," said Nordestgaard.

Observational Study Followed by Modeling Study

Nordestgaard and Martin Mortensen, MD, PhD, from Aarhus University Hospital, Denmark, compared the utility of different guidelines for primary prevention of ASCVD.

They first conducted an observational study of actual ASCVD events (nonfatal myocardial infarction, fatal coronary heart disease, stroke) during 10 years of follow-up in 45,750 Danish persons aged 40 to 75 years enrolled in the Copenhagen General Population Study. Participants were not using statins and did not have ASCVD at baseline.

Armed with the event data, the researchers then parsed through the different guideline recommendations and applied them to determine statin eligibility. They estimated the potential for reduction of all ASCVD events over 10 years through statin assignment of each guideline in persons 40 to 75 years of age.

Despite being founded on the same trial evidence, the guidelines have substantial differences, including in the recommended prediction model for ASCVD and in the risk threshold and low-density lipoprotein cholesterol cut-points for assignment of statin use, the authors write.

"Future updates of some guidelines may need to assign statin therapy to more patients to optimize ASCVD prevention," they conclude. "Future studies are needed to compare the cost-effectiveness of these 5 guidelines."

In an editorial[3] accompanying the publication, GB John Mancini, MD (University of British Columbia, Vancouver, BC, Canada), writes that guideline development is a complex process that arrives at conclusions that "reflect the priorities, preferences, local needs, and practical realities of intended users." Beyond that, they also reflect the structure imposed on the clinical trial findings, including the risk algorithms.

"One of the values of this paper is that it comes from a European member and they looked at it dispassionately and showed these comparative performances that are hard to just brush under the rug, so I think the 13% is something that needs to be reconsidered compared to the Canadian, US, and UK versions, again emphasizing that all the guidelines are based on the same science," Mancini said in an interview.

He added that the methods used by Mortensen and Nordestgaard are strong and that their paper reflected careful interpretation of the heavily nuanced individual guidelines.

This research was funded by Herlev and Gentofte Hospital, Copenhagen University Hospital, Aarhus University, and the Copenhagen County Foundation. Nordestgaard and Mortensen have disclosed no relevant financial relationships. Mancini reports being a member of the writing committee for the CCS dyslipidemia guidelines.

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