BALTIMORE – If all Americans eligible for statins under new American College of Cardiology/American Heart Association guidelines actually took them, thousands of deaths per year from cardiovascular disease might be prevented but at a cost of increased incidence of diabetes and myopathy.
The 2013 ACC/AHA guidelines expand criteria for the use of statins for primary prevention of CVD to more Americans (Circulation 2015;131:A05). Compliance with those guidelines would save 7,930 lives per year that would have been lost to CVD, according to Quanhe Yang, Ph.D., of the Centers for Disease Control and Prevention’s Division for Heart Disease and Stroke Prevention, and colleagues from the CDC and Emory University, Atlanta. Dr. Yang presented the findings at the American Heart Association Epidemiology and Prevention, Lifestyle and Cardiometabolic Health 2015 Scientific Sessions.
Statins are now indicated for primary prevention of CVD for anyone with an LDL cholesterol level greater than or equal to 190 mg/dL, for individuals aged 40-75 years with diabetes, and for those aged 40-75 years with LDL cholesterol greater than or equal to 70 mg/dL but less than 190 mg/dL who have at least a 7.5% estimated 10-year risk of developing atherosclerotic CVD. This means that an additional 24.2 million Americans are now eligible for statins but are not taking one, according to Dr. Yang and coinvestigators. However, “no study has assessed the potential impact of statin therapy under the new guidelines,” said Dr. Yang.
In order to obtain treatment group-specific atherosclerotic CVD, investigators first estimated hazard ratios for each treatment group by sex from the National Health and Nutrition Examination Survey III (NHANES III)–linked Mortality files. These hazard ratios were then applied to data from NHANES 2005-2010, the 2010 Multiple Cause of Death file, and the 2010 U.S. census to obtain age/race/sex-specific atherosclerotic CVD for each treatment group.
Applying the per-group hazard ratios, Dr. Yang and colleagues calculated that an annual 7,930 atherosclerotic CVD deaths would be prevented with full statin compliance, a reduction of 12.6%. However, modeling predicted an additional 16,400 additional cases of diabetes caused by statin use, he cautioned. More cases of myopathy would also occur, though the estimated number depends on whether the rate is derived from randomized, controlled trials (RCTs) or from population-based reports of myopathy. If the RCT data are used, just 1,510 excess cases of myopathy would be seen, in contrast to the 36,100 cases predicted by population-based data.
The study could model deaths caused by CVD only and not the reduction in disease burden of CVD that would result if all of the additional 24.2 million Americans took a statin, Dr Yang noted. Other limitations of the study included the lack of agreement in incidence of myopathy between RCTs and population-based studies, as well as the likelihood that the risk of diabetes increases with age and higher statin dose – effects not accounted for in the study.
Questioning after the talk focused on sex-specific differences in statin takers. For example, statin-associated diabetes is more common in women than men, another effect not accounted for in the study’s modeling, noted an audience member. Additionally, given that women have been underrepresented in clinical trials in general and in those for CVD in particular, some modeling assumptions in the present study may also lack full generalizability to women at risk for CVD.