Multiple US guidelines on statins create confusion

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More than 9m people in the US may miss out on the preventative effect of statins, if doctors choose one set of medical guidelines over another.

Reuters Health reports that according to a study, that’s because the government-backed US Preventive Services Task Force (USPSTF) set a higher threshold for use of the drugs, known as statins, than the American College of Cardiology and the American Heart Association (ACC/AHA).

“I would say we’re still searching for the perfect guidelines,” said lead author Michael Pencina, of Duke University in Durham, North Carolina.

The 2013 ACC/AHA guidelines recommend statins for people ages 40 to 75 with at least a 7.5% risk of having a heart attack or stroke in the next 10 years. The ACC/AHA also recommends statins for people with cardiovascular disease, for diabetics between ages 40 and 75 and for adults with high levels of “bad” low-density lipoprotein cholesterol.

The 2016 USPSTF recommendation endorses statins for people ages 40 to 75 with at least a 10% or greater risk of a heart attack or stroke over the next decade and at least one cardiovascular risk factor like diabetes or high blood pressure.

Pencina told is quoted in the report as saying that fewer people would be using statins under the more conservative USPSTF guidelines. “What we wanted to do is quantify the impact and look at what it means in terms of numbers.”

The researchers applied the recommendations to nationally representative data collected from 3,416 people without a history of cardiovascular disease between 2009 and 2014. Overall, 21.5% were already on statins to prevent heart attacks and strokes. An additional 24.3% would be on statins if all doctors followed the ACC/AHA guidelines, compared to an additional 15.8% if all doctors followed the USPSTF recommendation.
The difference between the two guidelines represents about 9.3m people in the US, the researchers write.

Under the USPSTF guidelines, some diabetics would be excluded from statin use. More than half of those excluded would be middle-aged adults with a more than 30% average risk of a cardiovascular event over the next 30 years.

“About one in three people are going to experience a cardiovascular event over the next 30 years,” said Pencina.

The USPSTF is quoted in the report as saying its recommendations are based on the best available evidence about a preventive service’s benefits and harms. “Because the USPSTF makes recommendations that are closely tied to the available evidence, we focused on recommending statins for the people who the evidence showed were most likely to benefit, though ultimately this decision should be made through a conversation between each patient and their doctor,” it said.

In its review of evidence, the USPSTF focused on 19 trials involving a total of 71,344 people who had no history of cardiovascular disease. Overall, people were 14% less likely to die during the study period if they were taking statins than if they were taking a dummy pill or nothing at all. The risk of serious side effects from statins was also low.

The USPSTF is always more conservative in its recommendations than professional organisations – not just for cholesterol, said Dr Steve Nissen, chair of the Robert and Suzanne Tomsich department of cardiovascular medicine at the Cleveland Clinic. “Whether you treat or not treat is frankly something that should be a discussion between patient and physician,” he said in the report. “That’s how I do it.”

Nissen, who was not involved in the new study, said some entity should step in to clear up the confusion between the USPSTF, ACC/AHA and several other statin guidelines. “I’m not terribly happy to have multiple guidelines floating around out there,” he said.

Pencina said it’s important for patients to be informed about their risk of cardiovascular disease and understand the risks and benefits of statins. “Both sets of guidelines – to their credit – recommend an informed decision between the patient and the clinician,” he said. “Those are crucial.”

Importance: There are important differences among guideline recommendations for using statin therapy in primary prevention. New recommendations from the US Preventive Services Task Force (USPSTF) emphasize therapy based on the presence of 1 or more cardiovascular disease (CVD) risk factors and a 10-year global CVD risk of 10% or greater.
Objective: To determine the difference in eligibility for primary prevention statin treatment among US adults, assuming full application of USPSTF recommendations compared with the American College of Cardiology/American Heart Association (ACC/AHA) guidelines.
Design, Setting, and Participants: National Health and Nutrition Examination Survey (NHANES) data (2009-2014) were used to assess statin eligibility under the 2016 USPSTF recommendations vs the 2013 ACC/AHA cholesterol guidelines among a nationally representative sample of 3416 US adults aged 40 to 75 years with fasting lipid data and triglyceride levels of 400 mg/dL or less, without prior CVD.
Exposures: The 2016 USPSTF recommendations vs 2013 ACC/AHA guidelines.
Main Outcomes and Measures: Eligibility for primary prevention statin therapy.
Results: Among the US primary prevention population represented by 3416 individuals in NHANES, the median weighted age was 53 years (interquartile range, 46-61), and 53% (95% CI, 52%-55%) were women. Along with the 21.5% (95% CI, 19.3%-23.7%) of patients who reported currently taking lipid-lowering medication, full implementation of the USPSTF recommendations would be associated with initiation of statin therapy in an additional 15.8% (95% CI, 14.0%-17.5%) of patients, compared with an additional 24.3% (95% CI, 22.3%-26.3%) of patients who would be recommended for statin initiation under full implementation of the 2013 ACC/AHA guidelines. Among the 8.9% of individuals in the primary prevention population who would be recommended for statins by ACC/AHA guidelines but not by USPSTF recommendations, 55% would be adults aged 40 to 59 years with a mean 30-year cardiovascular risk greater than 30%, and 28% would have diabetes.
Conclusions and Relevance: In this sample of US adults from 2009-2014, adherence to the 2016 USPSTF recommendations for statin therapy, compared with the 2013 ACC/AHA guidelines, could lead to a lower number of individuals recommended for primary prevention statin therapy, including many younger adults with high mean long-term CVD risk.

Neha J Pagidipati; Ann Marie Navar; Hillary Mulder; Allan D Sniderman; Eric D Peterson; Michael J Pencina

Reuters Health report
JAMA abstract

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