Statins for Prevention of Cardiovascular Disease in Adults
By Martina M. McGrath, MD
December 22, 2016
Cardiovascular disease (CVD) remains the leading killer of adults in the US, implicated in one out of every three deaths. Statins have shown significant benefit in secondary prevention of cardiovascular disease and mortality across a range of patient populations. Despite a large body of work, the data for primary prevention is less clear. Until now, the US Preventive Services Task Force (USPSTF) has not recommended statin therapy for primary prevention of CVD, but has instead suggested monitoring lipid levels as part of an overall CV risk assessment. In November 2016, they produced a set of recommendations published in JAMA, along with several accompanying editorials. Patients with LDL cholesterol >190mg/dL and those with familial hypercholesterolemia are excluded as statin therapy is recommended with this degree of hyperlipidemia. Lifestyle modification advice is recommended for all patients.
The recommendations and quality of evidence are as follows:
- Adults aged 40-75 years with no clinical history of CVD, ≥1 CVD risk factor, and calculated 10-year CVD event risk ≥10%:
Initiate low- to moderate-dose statins (Evidence Grade: B)
- Adults aged 40-75 years with no clinical history of CVD, ≥1 CVD risk factor, and calculated 10-year CVD event risk 7.5-10%:
Discuss with patient and selectively offer low- to moderate-dose statins (Evidence Grade: C)
- Adults aged 76 years and older with no history of CVD:
Recommendations are based on the results of 19 randomized controlled trials, involving 71,344 participants. For adults aged 40-75 years, treatment with low or moderate dose statin was associated with a reduction in all-cause mortality, with a pooled risk ratio of 0.86 (95% CI 0.80-0.93). Similar risk reduction was seen across groups of patients stratified by baseline risk, where those at greater risk had a similar degree of protection as those at lower risk. Therefore, the lower risk patients had ‘less to gain’ in absolute terms, hence the lower strength of recommendation for treatment in this group. For those aged >76 years, the panel concluded that there was insufficient evidence to produce a recommendation regarding potential benefit.
While the recommendations are based on data from large numbers of patients, several areas of controversy persist. There is minimal data regarding the utility of screening or treating dyslipidemia before the age of 40 years. Based on this, the USPSTF recommends against screening young adults and encourages the use of clinical judgment in caring for these patients. The dosing of statins, when to initiate low versus moderate intensity therapy, and whether to simply treat or to treat to a specific LDL goal, are important unresolved questions. The incidence of other adverse events such as myalgias, diabetes, and cognitive impairment did not appear to be significant in these trials. Indeed, other recent studies have queried as to whether these adverse effects are truly related to statins. However, as discussed in one of the accompanying editorials, accurate estimation of these risks becomes important when applying therapy across a large proportion of the population, particularly in those who may be expected to gain a smaller benefit from treatment than those enrolled in many of the original trials.
Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2016;316(19):2008-2024.
Dr. Martina McGrath is an instructor in medicine at Harvard Medical School, and a member of the Renal Division, Department of Medicine, at Brigham and Women’s Hospital, both in Boston.