Differential impact of muscle mass in women and men on heart failure and mortality after myocardial infarction

Background Reduced muscle mass is associated with abnormal cardiorespiratory fitness, decreased quality of life, and worse prognosis in the general population. There are no data on the potential differences in the association between muscle mass and heart failure after myocardial infarction (MI). Fat-free mass (FFM) is considered a surrogate for lean mass, which is regarded as the best surrogate for skeletal muscle mass. Purpose We investigated the association between FFM and congestive heart failure (CHF) as well as all-cause one-year mortality in men and women with MI who underwent percutaneous coronary intervention (PCI). Methods A retrospective study was conducted at a tertiary referral hospital with a 24/7 PCI service. We included 6493 MI patients who underwent PCI. FFM tertiles were created and further divided by sex, resulting in three female and three male groups. These groups were compared by sex and by FFM for CHF and one-year all-cause mortality. Data were analysed using descriptive statistics. Results The lowest incidence of CHF was observed in the high FFM group (third FFM tertile) in both sexes, followed by the second FFM tertile (medium FFM) and the first FFM tertile (low FFM) (7.5%, 10.9%, and 15.1% in men, and 7.9%, 14.5%, and 22.0% in women, respectively; p<0.0001 for both sexes and between sexes) (Figure 1). An inverse relationship between FFM and CHF was found in both sexes. The Spearman correlation coefficient showed a negative correlation between FFM and CHF in both sexes, which was stronger in women (r = -0.91; p<0.0001) than in men (r = -0.71; p<0.0001). A similar inverse relationship was observed between FFM tertiles and one-year mortality. The lowest one-year all-cause mortality occurred in the third FFM tertile (high FFM), followed by the second tertile (medium FFM) and the first tertile (low FFM), with rates of 5.8%, 12.2%, and 22.6% in men, and 6.9%, 16.9%, and 25.5% in women, respectively (p<0.0001 for both sexes and between sexes) (Figure 2). Conclusion In patients with MI treated with PCI, muscle mass was important for both sexes in relation to CHF and one-year mortality. Based on the correlation, low FFM is expected to be more harmful in women than in men. According to our results, women with low muscle mass are particularly at risk for CHF and mortality and should receive special attention after MI.