Early β-blocker use and in-hospital mortality in patients with Takotsubo cardiomyopathy

OBJECTIVE: A catecholamine-mediated mechanism has been implicated in the pathogenesis of Takotsubo cardiomyopathy (TC). However, the impact of β-blockers in acute-phase management of TC remains uncertain. This study aimed to examine whether early β-blocker use in TC was associated with lower in-hospital mortality. METHODS: This was a retrospective cohort study using the Diagnosis Procedure Combination nationwide inpatient database in Japan. Patients with TC aged ≥20 years who were admitted to acute-care hospitals between 2010 and 2014 were identified. Thirty-day in-hospital mortality was compared between patients who started β-blocker therapy on hospitalisation day 1 or 2 (early β-blocker group) and those who did not receive a β-blocker during hospitalisation (control group) using propensity score-matching and instrumental variable analyses. RESULTS: Of 2672 eligible patients (female, 81.5%; 423 early β-blocker therapy, 2249 controls) from 615 hospitals, 1:4 propensity score-matching created a cohort of 2110 patients (422 early β-blocker therapy, 1688 controls). There was no significant difference in 30-day in-hospital mortality between the early β-blocker group and control group (2.4% vs 2.0%, p=0.703; risk difference, 0.4%; 95% CI, -1.2% to 2.0%). Logistic regression analysis did not show a significant association between early β-blocker use and 30-day in-hospital mortality (OR, 1.17; 95% CI 0.58 to 2.37). Instrumental variable analysis also found that early β-blocker use was not associated with lower 30-day in-hospital mortality (risk difference, 1.2%; 95% CI -3.1% to 5.5%). CONCLUSIONS: This study found no significant association between early β-blocker use and in-hospital mortality in patients with TC.