Reduced mortality during the COVID-19 outbreak in Japan, 2020: a two-stage interrupted time-series design.

BACKGROUND: Coronavirus disease 2019 (COVID-19) continues to be a major global health burden. This study aims to estimate the all-cause excess mortality occurring in the COVID-19 outbreak in Japan, 2020, by sex and age group. METHODS: Daily time series of mortality for the period January 2015-December 2020 in all 47 prefectures of Japan were obtained from the Ministry of Health, Labour and Welfare, Japan. A two-stage interrupted time-series design was used to calculate excess mortality. In the first stage, we estimated excess mortality by prefecture using quasi-Poisson regression models in combination with distributed lag non-linear models, adjusting for seasonal and long-term variations, weather conditions and influenza activity. In the second stage, we used a random-effects multivariate meta-analysis to synthesize prefecture-specific estimates at the nationwide level. RESULTS: In 2020, we estimated an all-cause excess mortality of -20 982 deaths [95% empirical confidence intervals (eCI): -38 367 to -5472] in Japan, which corresponded to a percentage excess of -1.7% (95% eCI: -3.1 to -0.5) relative to the expected value. Reduced deaths were observed for both sexes and in all age groups except those aged <60 and 70-79 years. CONCLUSIONS: All-cause mortality during the COVID-19 outbreak in Japan in 2020 was decreased compared with a historical baseline. Further evaluation of cause-specific excess mortality is warranted.

COVID-19 pandemic is associated with mechanical complications in patients with ST-elevation myocardial infarction.

OBJECTIVE: Although there are regional reports that the COVID-19 pandemic is associated with a reduction in acute myocardial infarction presentations and primary percutaneous coronary intervention (PCI) procedures, little is known about the impact of the COVID-19 pandemic on mechanical complications resulting from ST-segment elevation myocardial infarction (STEMI) and mortality. METHODS: This single-centre retrospective cohort study analysed presentations, incidence of mechanical complications, and mortality in patients with STEMI before and after a state of emergency was declared due to the COVID-19 pandemic by the Japanese government on 7 April 2020. RESULTS: We analysed 359 patients with STEMI hospitalised before the declaration and 63 patients hospitalised after the declaration. The proportion of patients with late presentation was significantly higher after the declaration than before (25.4% vs 14.2%, p=0.03). The incidence of late presentation was significantly higher during the COVID-19 pandemic than before (incidence rate ratio (IRR), 2.41; 95% CI, 1.37 to 4.05; p=0.001, even after adjusting for month (IRR, 2.61; 95% CI, 1.33 to 5.13; p<0.01). Primary PCI was performed significantly less often after the declaration than before (68.3% vs 82.5%, p=0.009). The mechanical complication resulting from STEMI occurred in 13 of 359 (3.6%) patients before the declaration and 9 of 63 (14.3%) patients after the declaration (p<0.001). However, the incidence of in-hospital death (before, 6.2% vs after, 6.4%, p=0.95) was comparable. CONCLUSIONS: Following the COVID-19 pandemic, an increased incidence of mechanical complications resulting from STEMI was observed. Instructing people to stay at home, without effectively educating them to immediately seek medical attention when suffering symptoms of a heart attack, may worsen outcomes in patients with STEMI.