Background Little is known about the prognostic implications of frailty, a state of susceptibility to stressors and poor recovery to homeostasis in older people, after myocardial infarction ( MI ). Methods and Results We studied 3944 MI patients aged ≥65 years treated at 41 Australian hospitals from 2009 to 2016 in the CONCORDANCE ( Australian Cooperative National Registry of Acute Coronary Care, Guideline Adherence and Clinical Events ) registry. Frailty index ( FI ) was determined using the health deficit accumulation method. All-cause and cardiac-specific mortality at 6 months were compared between frail ( FI >0.25) and nonfrail ( FI ≤0.25) patients. Among 1275 patients with ST-segment-elevation MI (STEMI), 192 (15%) were frail, and among 2669 non-STEMI ( NSTEMI) patients, 902 (34%) were frail. Compared with nonfrail counterparts, frail STEMI patients received 30% less reperfusion therapy and 22% less revascularization during index hospitalization; frail NSTEMI patients received 30% less diagnostic angiography and 39% less revascularization. Unadjusted 6-month all-cause mortality ( STEMI : 13% versus 3%; NSTEMI : 13% versus 4%) and cardiac-specific mortality ( STEMI : 6% versus 1.4%, NSTEMI : 3.2% versus 1.2%) were higher among frail patients. After adjustment for known prognosticators, FI was significantly associated with higher 6-month all-cause ( STEMI : odds ratio: 1.74 per 0.1 FI [ 95% confidence interval, 1.37-2.22], P<0.001; NSTEMI : odds ratio: 1.62 per 0.1 FI [95% confidence interval, 1.40-1.87], P<0.001) but not cardiac-specific mortality ( STEMI : P=0.99; NSTEMI : P=0.93). Conclusions Frail patients receive lower rates of invasive cardiac care during MI hospitalization. Increased frailty was independently associated with increased postdischarge all-cause mortality but not cardiac-specific mortality. These findings inform identification of frailty during MI hospitalization as a potential opportunity to address competing risks for mortality in this high-risk population.
Keywords: frailty; health services research; myocardial infarction; outcomes.