To the Editor

Zhang et al. conducted a meta-analysis on the association between frailty and mortality in older patients with acute coronary syndromes (ACS) [1]. Pooled hazard ratios (HRs) of frailty for short-term, medium-term, and long-term mortality were 3.67, 4.09, and 1.66, respectively, and risk of frailty on long-term mortality was attenuated. I suppose that frailty status might be easily changed in the elderly and regular check of frailty status should be conducted to prevent worsening health status. I am presenting two issues regarding this study.

First, Man et al. also conducted a meta-analysis regarding the effect of frailty on all-cause mortality in patients with ACS, by classifying all-cause mortality into short term (≤ 6 months) and long term (≥ 12 months) [2]. Adjusted HRs [95% confidence intervals (CIs)] of frailty for in-hospital death, short-term all-cause mortality, and long-term all-cause mortality were 5.49 (2.19–13.77), 3.56 (1.96–6.48), and 2.44 (1.92–3.12). In addition, Adjusted HR (95% CI) of prefrailty for all-cause mortality was 1.65 (1.01–2.69). Although mortality risk was attenuated by long-term follow-up, significant increase of all-cause mortality was kept over one year. As the mortality risk of prefrailty was also observed, early detection of frailty and its improvement are needed.

Second, Núñez et al. examined the association between frailty status and long-term mortality in elderly patients with ACS [3]. Adjusted HRs (95% CIs) of frailty with Fried score of ≥ 3 for all-cause mortality in males and females were 1.89 (1.25–2.85) and 0.92 (0.57–1.49), and there was a sex difference of the association. As one of the explanations, Hanlon et al. reported that aging and comorbid conditions might be related to the sex difference of the association between frailty status and mortality [4]. Although acceptable mechanism of sex difference might not be confirmed, biopsychosocial factors should be comprehensively evaluated to elucidate sex difference of the association.