Off-hours presentation does not affect in-hospital mortality of Japanese patients with acute myocardial infarction: J-MINUET substudy

Background The association between patients with acute myocardial infarction (AMI) who present during off-hours and clinical outcomes has not been fully elucidated. Methods We investigated 3283 consecutive patients with AMI who were selected from a prospective, nationwide, multicenter registry (J-MINUET) database comprising 28 institutions in Japan between July 2012 and March 2014 to determine the current impact of off-hours presentation on in-hospital mortality among Japanese patients with AMI. Results Among the patients, 52% presented in off-hours. Baseline characteristics were comparable, although those who presented during off-hours were younger and had a higher incidence of ST-elevation myocardial infarction and advanced Killip Class. The time from symptom onset to presentation time was shorter in off-hour patients (120 min, interquartile range 60 to 256 vs. 215 min, interquartile range 90 to 610, p < 0.0001). In contrast, 85% of patients underwent primary percutaneous coronary intervention (PCI) and door to balloon time was comparable between the groups (74 min, interquartile range 52 to 113 vs. 75 min, interquartile range 52 to 126, p = 0.34). The rates of in-hospital mortality were comparable (6.2% vs 6.8%, p = 0.39). Multivariate logistic regression analysis revealed that off-hours presentation was not significantly associated with in-hospital mortality [odds ratio (OR) 0.94; 95% CI, 0.68–1.30, p = 0.70]. Conclusion The clinical impact of presenting during off-hours or regular hours on AMI patients in Japan is comparable in contemporary practice. Trial registration UMIN Unique trial Number: UMIN000010037.