New data show that, after a myocardial infarction, significantly fewer women than men fill a prescription for high-intensity statin therapy. These findings are despite initiatives aimed at reducing historic sex differences in guideline-recommended therapy.
Sanne AE Peters (The George Institute for Global Health, University of Oxford, Oxford, UK) and others report in the Journal of the American College of Cardiology that “historically, women have been less likely than men to receive guideline-recommended statin therapy for the secondary prevention of myocardial infarction”. They add a large meta-analysis of individual participant data of randomised controlled trials have demonstrated that the benefits of more-intensive vs. less-intensive statin therapy, among patients with a history of vascular disease, are similar between men and women. Furthermore, 2013 US guidelines on managing cholesterol do not make sex-specific recommendations on statin dosage.
Noting that “substantial efforts”, such as Go Red for Women, have been made to reduce sex differences in cardiovascular disease, Peters et al comment it is unknown whether these efforts (as well as the guidelines) have reduced the gap between men and women regarding the differences in high-intensity statin therapy. “Moreover, although the overall uptake of high-intensity statins in secondary prevention has increased substantially in recent years, sex differences in the use of high-intensity statin therapy following a hospital admission for myocardial infarction have not been assessed in detail,” they add.
The aim of the present study, therefore, was to review contemporary use of high-intensity statin therapy following a myocardial infarction in men and in women. The authors also sought to “identify factors associated with the underutilisation of high-intensity statins among women.”
Using data from US commercial and government health insurance databases, they identified 39,256 women and 49,000 men who filled a statin prescription for statin therapy following hospital discharge for myocardial infarction. Peters et al comment: “After adjustment for demographic characteristics comorbidities, and healthcare use, the women-to-men risk ratio for high-intensity statin use were 0.91 in the total population of statin users, 0.91 among those with no prior statin use, 0.87 among those with low/moderate-intensity statin use, and 0.98 among those with prior high-intensity statin use (p for interaction by prior statin use and dosage <0.001).”
According to the authors, the sex differences were largest among those without prior statin use and those with prior low/moderate intensity use “suggesting that women are less likely than men to get uptitrated or less likely to initiate high-intensity statin therapy post myocardial infarction”.
The sex differences were also larger among the youngest and oldest patients. This finding, Peters et al state, is “concerning” because the “oldest are at the highest risk, whereas young women have recently been shown to have the slowest rate of decline in cardiovascular disease rate in the United States”.
Furthermore, they note that there was no evidence of diminishing of the sex differential in the use of high-intensity statin post myocardial infarction following the 2013 guidelines, commenting: “In the overall population, the women-to-men risk ratio ranged from 0.94 in 2007 to 0.91 in 2015.”
Peters et al discuss several reasons for the reasons why women are still less likely to receive high-intensity statin therapy after a myocardial infarction. This includes the fact some studies have suggested that women are more likely to experience side-effects from statin therapy from men, but data from six randomised controlled trials indicate that muscle symptoms (a known side-effect of statin therapy) was slightly higher in women in both placebo and statin groups. “These suggest that the risk for statin-associated muscle symptoms should not be a barrier to prescribing high-intensity statin therapy to women,” the authors comment.
Concluding, they write: “The factors attributable to these sex differences need to be elucidated. Increased awareness of the benefits of high-intensity statins is needed to reinforce the use of high-intensity statins among women with a prior myocardial infarction.”
Peters told Cardiovascular News: “The discrepancies in high-intensity statin use may explain, at least in part, why mortality rates for women with a history of heart disease and stroke are higher than for men. Our research suggests some deaths could be prevented if the guidelines on treatment with high-intensity statins were adhered to.”
She adds: “We need further research to understand the barriers to guideline-recommended treatment in women. There is clearly more work to be done to raise awareness of the benefits of high-intensity statins for both women and men who have experienced heart attacks, in order to eliminate these disparities.”