Impact of Coronavirus Disease 2019 (COVID-19) Outbreak on Emergency Patients Hospitalized With Cardiocerebrovascular Diseases in Osaka Prefecture, Japan　― A Population-Based Study ―

Kenta Tanaka; Yusuke Katayama; Tetsuhisa Kitamura; Hisaya Dohmi; Jun Masui; Tomoya Hirose; Shunichiro Nakao; Jotaro Tachino; Ling Zha; Tomotaka Sobue; Jun Oda; Tetsuya Matsuoka

doi:10.1253/circj.CJ-23-0298

Abstract

Background: Little is known about the transport and outcomes of emergency patients with cardiocerebrovascular diseases in Japan before and during the COVID-19 pandemic.

Methods and Results: Data were extracted from a population-based registry in Osaka, Japan, from 2019 to 2021. There were almost no differences in the numbers of emergency patients hospitalized with myocardial infarction, stroke, or heart failure or their deaths. However, the number of cases of difficulty obtaining patient acceptance by hospitals increased in 2020 and 2021 compared with 2019.

Conclusions: The numbers of emergency patients hospitalized with cardiocerebrovascular diseases and their deaths in Osaka were not affected by the COVID-19 epidemic.

The novel coronavirus disease 2019 (COVID-19) was confirmed in Wuhan, China, in December 2019, and has spread around the world. In Japan, the first COVID-19 case was identified on 16 January 2020, and this infectious disease has spread rapidly since then.¹

For patients with emergency cardiocerebrovascular diseases, prompt transport to a medical institution after disease onset is important in determining the patient’s outcome. However, during the period of the COVID-19 pandemic, the Emergency Medical Service system may have been affected, and patients with cardiocerebrovascular diseases may not have been transported to emergency medical institutions promptly and appropriately.

Several studies have investigated the transportation and outcome of patients with cardiovascular diseases using the data of several hospital emergency departments from 2019 to 2020. However, no studies have analyzed these factors from 2019 to 2021 using population-based data, especially for patients with cardiocerebrovascular diseases. This study used population-based data to evaluate the epidemiology and outcome of emergency patients hospitalized with cardiocerebrovascular diseases transported to medical institutions in Osaka Prefecture, Japan, during that period.

Methods

This was a retrospective descriptive study with a study period from 1 January 2019 to 31 December 2021. We used the database of a population-based registry of emergency patients that comprises both ambulance and in-hospital records managed by the Osaka emergency information Research Intelligent Operation Network (ORION) system, which is operated by Osaka Prefecture and covers all patients transported to critical care centers and emergency hospitals in the prefecture. Information on the ORION database has been previously described in detail.² This study was approved by the Ethics Committee of the Osaka University Graduate School of Medicine (No. 15003), and was conducted in accordance with the Declaration of Helsinki. In 2020, 8,837,685 people lived in the 1,905-km² area of Osaka Prefecture.³

Subjects undergoing interhospital transport were excluded. The outcome measures were the number of emergency transports, difficulties in obtaining patient acceptance by hospitals (defined as ambulance crews having to make ≥4 phone calls to hospitals before obtaining hospital acceptance of the patient as well as staying at the scene for ≥30 min), and deaths among hospitalized emergency patients as assessed at 21 days after hospitalization. We used the outcome measures of 2019 as the reference (control period before COVID-19) and compared them by year and by month for 2020 (1st year of the COVID-19 pandemic) and 2021 (2nd year of the COVID-19 pandemic).

Those patients whose diagnosis at hospital arrival was cardiocerebrovascular disease such as acute myocardial infarction (AMI: I21–I23 of the International Classification of Diseases, 10th revision codes), cerebral infarction (I63), intracranial hemorrhage (I61, I62), subarachnoid hemorrhage (SAH: I60), aortic aneurysm and dissection (I71), pulmonary embolism (PE: I26), heart failure (HF: I50), or acute pericarditis/acute myocarditis (I30, I40). The analyses regarding difficulties in obtaining patient acceptance by hospitals and deaths of patients whose diagnosis was acute pericarditis/acute myocarditis were excluded because of the small number of cases.

We calculated the incidence rate ratio (IRR) and its 95% confidence interval (CI) by year and by month for 2020 and 2021, respectively, using a Poisson regression model with year 2019 as the control year. Statistical analyses were implemented using STATA MP version 16.0 (STAT Corp., College Station, TX, USA).

Results

The total number of emergency hospitalized patients with cardiocerebral vascular diseases in Osaka Prefecture was 23,743, 23,819, and 24,163 in 2019, 2020, and 2021, respectively (Figure).

Figure.

Study flowchart.

Table 1 shows the number of emergency patients hospitalized for cardiocerebrovascular diseases in Osaka from 2019 to 2021 and the IRR (95% CI) values. The total number of hospitalized emergency patients with AMI was 2,231, 2,288, and 2,221 in 2019, 2020, and 2021, respectively, and there were no significant differences between 2020 and 2019 (IRR: 1.03, 95% CI: 0.97–1.09) or 2021 and 2019 (IRR: 1.00, 95% CI: 0.94–1.06). There was also no significant difference in the number of emergency patients hospitalized with cerebral infarction between 2019 and 2020 (IRR: 0.99, 95% CI: 0.96–1.02), but a slight increase in the number of emergency patients hospitalized with cerebral infarction was observed in 2021 compared with 2019 (IRR: 1.03, 95% CI: 1.00–1.06). The numbers of other cardiocerebrovascular diseases showed no significant differences in 2020 and 2021 compared with 2019.

Table 1. Number of Emergency Patients Hospitalized for Cardiocerebrovascular Diseases by Month and Year in Osaka, Japan

Cardiocerebrovascular disease	January	February	March	April	May	June	July	August	September	October	November	December	Total
AMI
2019	199	183	178	160	194	167	206	183	173	184	202	202	2,231
2020	239	220	195	172	152	164	194	210	160	189	179	214	2,288
2021	186	182	204	168	170	173	167	173	162	200	184	252	2,221
IRR^a (95% CI)	1.20 (0.99–1.46)	1.20 (0.98–1.47)	1.10 (0.89–1.35)	1.08 (0.86–1.34)	0.78 (0.63–0.97)	0.98 (0.79–1.23)	0.94 (0.77–1.15)	1.15 (0.94–1.41)	0.92 (0.74–1.15)	1.03 (0.83–1.27)	0.89 (0.72–1.09)	1.06 (0.87–1.29)	1.03 (0.97–1.09)
IRR^b (95% CI)	0.93 (0.76–1.15)	0.99 (0.81–1.23)	1.15 (0.93–1.41)	1.05 (0.84–1.31)	0.88 (0.71–1.08)	1.04 (0.83–1.29)	0.81 (0.66–1.00)	0.95 (0.76–1.17)	0.94 (0.75–1.17)	1.09 (0.89–1.34)	0.91 (0.74–1.12)	1.25 (1.03–1.51)	1.00 (0.94–1.06)
Cerebral infarction
2019	775	665	740	773	730	697	710	671	713	703	765	795	8,737
2020	767	679	731	743	686	723	724	728	675	726	711	780	8,673
2021	829	679	786	743	725	725	711	716	685	769	792	866	9,026
IRR^a (95% CI)	0.99 (0.89–1.09)	1.02 (0.92–1.14)	0.99 (0.89–1.10)	0.96 (0.87–1.06)	0.94 (0.85–1.04)	1.04 (0.93–1.15)	1.02 (0.92–1.13)	1.08 (0.98–1.21)	0.95 (0.85–1.05)	1.03 (0.93–1.15)	0.93 (0.84–1.03)	0.98 (0.89–1.08)	0.99 (0.96–1.02)
IRR^b (95% CI)	1.07 (0.97–1.18)	1.02 (0.92–1.14)	1.06 (0.96–1.18)	0.96 (0.87–1.06)	0.99 (0.89–1.10)	1.04 (0.94–1.16)	1.00 (0.90–1.11)	1.07 (0.96–1.19)	0.96 (0.86–1.07)	1.09 (0.99–1.21)	1.04 (0.94–1.14)	1.09 (0.99–1.20)	1.03 (1.00–1.06)
IH
2019	374	358	408	358	288	269	276	261	255	314	365	389	3,915
2020	391	379	379	334	290	298	291	276	265	384	369	398	4,054
2021	411	360	361	328	298	268	275	256	267	374	339	393	3,930
IRR^a (95% CI)	1.05 (0.90–1.21)	1.06 (0.91–1.23)	0.93 (0.81–1.07)	0.93 (0.80–1.09)	1.01 (0.85–1.19)	1.11 (0.94–1.31)	1.05 (0.89–1.25)	1.06 (0.89–1.26)	1.04 (0.87–1.24)	1.22 (1.05–1.42)	1.01 (0.87–1.17)	1.02 (0.89–1.18)	1.04 (0.99–1.08)
IRR^b (95% CI)	1.10 (0.95–1.27)	1.01 (0.87–1.17)	0.88 (0.77–1.02)	0.92 (0.79–1.07)	1.03 (0.88–1.22)	1.00 (0.84–1.18)	1.00 (0.84–1.18)	0.98 (0.82–1.17)	1.05 (0.88–1.25)	1.19 (1.02–1.39)	0.93 (0.80–1.08)	1.01 (0.88–1.17)	1.00 (0.96–1.05)
SAH
2019	98	68	88	76	71	80	57	68	68	72	79	82	907
2020	74	74	66	70	56	68	69	59	78	87	75	78	854
2021	87	79	97	59	75	64	59	58	74	79	65	85	881
IRR^a (95% CI)	0.76 (0.55–1.03)	1.09 (0.77–1.54)	0.75 (0.54–1.04)	0.92 (0.66–1.29)	0.79 (0.55–1.14)	0.85 (0.61–1.19)	1.21 (0.84–1.75)	0.87 (0.60–1.25)	1.15 (0.82–1.61)	1.21 (0.87–1.67)	0.95 (0.68–1.32)	0.95 (0.69–1.31)	0.94 (0.86–1.03)
IRR^b (95% CI)	0.89 (0.66–1.20)	1.16 (0.83–1.63)	1.10 (0.82–1.49)	0.78 (0.54–1.11)	1.06 (0.75–1.48)	0.80 (0.57–1.13)	1.04 (0.71–1.52)	0.85 (0.59–1.23)	1.09 (0.77–1.54)	1.10 (0.79–1.53)	0.82 (0.58–1.16)	1.04 (0.76–1.42)	0.97 (0.88–1.07)
Aortic aneurysm and dissection
2019	83	72	72	61	67	47	47	49	53	78	88	89	806
2020	64	77	67	62	55	51	46	46	70	85	66	94	783
2021	91	72	66	70	56	58	52	50	61	81	86	84	827
IRR^a (95% CI)	0.77 (0.55–1.08)	1.07 (0.77–1.50)	0.93 (0.66–1.32)	1.02 (0.70–1.47)	0.82 (0.56–1.19)	1.09 (0.72–1.65)	0.98 (0.64–1.50)	0.94 (0.61–1.43)	1.32 (0.91–1.92)	1.09 (0.79–1.50)	0.75 (0.54–1.04)	1.06 (0.78–1.43)	0.97 (0.88–1.07)
IRR^b (95% CI)	1.10 (0.81–1.49)	1.00 (0.71–1.41)	0.92 (0.65–1.30)	1.15 (0.80–1.64)	0.84 (0.58–1.21)	1.23 (0.83–1.85)	1.11 (0.73–1.68)	1.02 (0.67–1.55)	1.15 (0.78–1.70)	1.04 (0.75–1.44)	0.98 (0.72–1.33)	0.94 (0.69–1.29)	1.03 (0.93–1.13)
PE
2019	14	23	24	23	12	12	21	22	19	23	16	23	232
2020	30	29	12	20	16	15	15	20	16	17	17	22	229
2021	31	25	21	15	18	17	21	13	21	18	24	18	242
IRR^a (95% CI)	2.14 (1.10–4.37)	1.26 (0.70–2.28)	0.50 (0.23–1.04)	0.87 (0.45–1.66)	1.33 (0.59–3.09)	1.25 (0.55–2.92)	0.71 (0.34–1.45)	0.91 (0.47–1.75)	0.84 (0.41–1.73)	0.74 (0.37–1.45)	1.06 (0.50–2.25)	0.96 (0.51–1.80)	0.99 (0.82–1.19)
IRR^b (95% CI)	2.21 (1.14–4.50)	1.09 (0.59–2.00)	0.88 (0.46–1.64)	0.65 (0.32–1.30)	1.50 (0.68–3.41)	1.42 (0.64–3.25)	1.00 (0.52–1.92)	0.59 (0.27–1.23)	1.11 (0.57–2.17)	0.78 (0.40–1.52)	1.50 (0.76–3.02)	0.78 (0.40–1.52)	1.04 (0.87–1.25)
HF
2019	837	592	611	619	585	473	460	475	400	505	592	714	6,863
2020	814	713	661	527	476	449	445	462	463	541	601	743	6,895
2021	792	627	694	556	490	473	479	446	450	545	650	762	6,964
IRR^a (95% CI)	0.97 (0.88–1.07)	1.20 (1.08–1.35)	1.08 (0.97–1.21)	0.85 (0.76–0.96)	0.81 (0.72–0.92)	0.95 (0.83–1.08)	0.97 (0.85–1.10)	0.97 (0.85–1.11)	1.16 (1.01–1.33)	1.07 (0.95–1.21)	1.02 (0.90–1.14)	1.04 (0.94–1.15)	1.00 (0.97–1.04)
IRR^b (95% CI)	0.95 (0.86–1.04)	1.06 (0.95–1.19)	1.14 (1.02–1.27)	0.90 (0.80–1.01)	0.84 (0.74–0.95)	1.00 (0.88–1.14)	1.04 (0.91–1.19)	0.94 (0.82–1.07)	1.13 (0.98–1.29)	1.08 (0.95–1.22)	1.10 (0.98–1.23)	1.07 (0.96–1.18)	1.01 (0.98–1.05)
Acute pericarditis or acute myocarditis
2019	7	3	3	3	6	3	5	4	3	5	3	7	52
2020	7	3	4	5	4	4	2	5	1	5	1	2	43
2021	8	5	5	4	7	8	6	10	6	7	4	2	72
IRR^a (95% CI)	1.00 (0.30–3.34)	1.00 (0.13–7.47)	1.33 (0.23–9.10)	1.67 (0.32–10.73)	0.67 (0.14–2.81)	1.33 (0.23–9.10)	0.40 (0.04–2.44)	1.25 (0.27–6.30)	0.33 (0.01–4.15)	1.00 (0.23–4.35)	0.33 (0.01–4.15)	0.29 (0.03–1.50)	0.83 (0.54–1.26)
IRR^b (95% CI)	1.14 (0.36–3.70)	1.67 (0.32–10.73)	1.67 (0.32–10.73)	1.33 (0.23–9.10)	1.17 (0.34–4.20)	2.67 (0.64–15.61)	1.20 (0.31–4.97)	2.50 (0.72–10.92)	2.00 (0.43–12.36)	1.40 (0.38–5.59)	1.33 (0.23–9.10)	0.29 (0.03–1.50)	1.38 (0.96–2.02)

^aIRR is for 2020 vs. 2019. ^bIRR is for 2021 vs. 2019. AMI, acute myocardial infarction; CI, confidence interval; HF, heart failure; IH, intracerebral hemorrhage; IRR, incidence rate ratio; PE, pulmonary embolism; SAH, subarachnoid hemorrhage.

Table 2 shows the number of difficulties in obtaining patient acceptance by hospitals for emergency patients with cardiocerebrovascular diseases and the IRR (95% CI) values for each month. Significant increases were seen in the number of difficulties in acceptance by hospitals of emergency patients in 2020 compared with 2019 for those with PE (IRR: 5.50, 95% CI: 1.20–51.07) and HF (IRR: 1.93, 95% CI: 1.55–2.43). Likewise, significant increases were also seen in the number of difficulties in patient acceptance by hospitals of emergency patients in 2021 compared with 2019 for those with AMI (IRR: 2.95, 95% CI: 1.75–5.17), cerebral infarction (IRR: 1.54, 95% CI: 1.25–1.90), intracranial hemorrhage (IRR: 2.12, 95% CI: 1.55–2.93), SAH (IRR: 2.08, 95% CI: 1.04–4.38), aortic aneurysm and dissection (IRR: 1.89, 95% CI: 1.06–3.50), and HF (IRR: 3.81, 95% CI: 3.12–4.69). In particular, when comparing HF by month, the IRR in 2021 compared with 2019 increased significantly in April (IRR, 6.75; 95% CI, 3.19–16.42) and May (IRR, 5.70; 95% CI, 2.88–12.52), which corresponded to the 4th wave of COVID-19 infections in Japan, and in August (IRR, 11.00; 95% CI, 4.00–42.15), corresponding to the 5th wave, and continued to increase significantly thereafter.

Table 2. Number of Difficulties in Obtaining Hospital Acceptance for Emergency Patients Hospitalized for Cardiocerebrovascular Diseases by Month and Year in Osaka, Japan

Cardiocerebrovascular disease	January	February	March	April	May	June	July	August	September	October	November	December	Total
AMI
2019	1	2	1	0	3	2	2	3	2	0	2	2	20
2020	5	3	0	5	5	1	0	3	2	2	2	6	34
2021	7	3	5	5	11	1	3	6	7	6	2	3	59
IRR^a (95% CI)	5.00 (0.56–236.49)	1.50 (0.17–17.96)	NA	NA	1.67 (0.32–10.73)	0.50 (0.01–9.60)	NA	1.00 (0.13–7.47)	1.00 (0.07–13.80)	NA	1.00 (0.07–13.80)	3.00 (0.54–30.39)	1.70 (0.95–3.12)
IRR^b (95% CI)	7.00 (0.90–315.48)	1.50 (0.17–17.96)	5.00 (0.56–236.49)	NA	3.67 (0.97–20.47)	0.50 (0.01–9.60)	1.50 (0.17–17.96)	2.00 (0.43–12.36)	3.50 (0.67–34.53)	NA	1.00 (0.07–13.80)	1.50 (0.17–17.96)	2.95 (1.75–5.17)
Cerebral infarction
2019	22	20	21	19	12	7	3	9	14	8	8	10	153
2020	13	12	9	20	17	7	7	12	6	14	7	19	143
2021	39	23	13	22	28	13	10	24	16	20	15	13	236
IRR^a (95% CI)	0.59 (0.27–1.23)	0.60 (0.27–1.29)	0.43 (0.17–0.98)	1.05 (0.53–2.08)	1.42 (0.64–3.25)	1.00 (0.30–3.34)	2.33 (0.53–13.98)	1.33 (0.52–3.58)	0.43 (0.13–1.19)	1.75 (0.69–4.81)	0.88 (0.27–2.76)	1.90 (0.84–4.57)	0.93 (0.74–1.18)
IRR^b (95% CI)	1.77 (1.03–3.14)	1.15 (0.60–2.21)	0.62 (0.28–1.30)	1.16 (0.60–2.26)	2.33 (1.15–5.04)	1.86 (0.69–5.50)	3.33 (0.86–18.85)	2.67 (1.20–6.52)	1.14 (0.52–2.53)	2.50 (1.05–6.56)	1.88 (0.75–5.11)	1.30 (0.53–3.31)	1.54 (1.25–1.90)
IH
2019	8	12	2	8	6	2	5	2	2	2	4	7	60
2020	3	7	7	10	4	7	4	7	3	4	9	11	76
2021	17	11	9	17	15	7	10	8	10	10	5	8	127
IRR^a (95% CI)	0.38 (0.06–1.56)	0.58 (0.19–1.61)	3.50 (0.67–34.53)	1.25 (0.44–3.64)	0.67 (0.14–2.81)	3.50 (0.67–34.53)	0.80 (0.16–3.72)	3.50 (0.67–34.53)	1.50 (0.17–17.96)	2.00 (0.29–22.11)	2.25 (0.63–10.00)	1.57 (0.56–4.78)	1.27 (0.89–1.81)
IRR^b (95% CI)	2.13 (0.87–5.69)	0.92 (0.37–2.27)	4.50 (0.93–42.80)	2.13 (0.87–5.69)	2.50 (0.92–7.86)	3.50 (0.67–34.53)	2.00 (0.62–7.46)	4.00 (0.80–38.67)	5.00 (1.07–46.93)	5.00 (1.07–46.93)	1.25 (0.27–6.30)	1.14 (0.36–3.70)	2.12 (1.55–2.93)
SAH
2019	0	1	4	2	1	0	1	0	2	0	1	1	13
2020	1	1	0	3	2	2	0	2	2	1	0	2	16
2021	3	1	3	5	4	1	1	0	2	0	2	5	27
IRR^a (95% CI)	NA	1.00 (0.01–78.50)	NA	1.50 (0.17–17.96)	2.00 (0.10–117.99)	NA	NA	NA	1.00 (0.07–13.80)	NA	NA	2.00 (0.10–117.99)	1.23 (0.56–2.78)
IRR^b (95% CI)	NA	1.00 (0.01–78.50)	0.75 (0.11–4.43)	2.50 (0.41–26.25)	4.00 (0.40–196.99)	NA	1.00 (0.01–78.50)	NA	1.00 (0.07–13.80)	NA	2.00 (0.10–117.99)	5.00 (0.56–236.49)	2.08 (1.04–4.38)
Aortic aneurysm and dissection
2019	0	4	1	1	1	0	3	4	2	2	1	0	19
2020	1	3	0	1	1	0	1	1	1	3	1	6	19
2021	9	2	0	4	5	0	0	2	3	6	1	4	36
IRR^a (95% CI)	NA	0.75 (0.11–4.43)	NA	1.00 (0.01–78.50)	1.00 (0.01–78.50)	NA	0.33 (0.01–4.15)	0.25 (0.01–2.53)	0.50 (0.01–9.60)	1.50 (0.17–17.96)	1.00 (0.01–78.50)	NA	1.00 (0.50–2.00)
IRR^b (95% CI)	NA	0.50 (0.05–3.49)	NA	4.00 (0.40–196.99)	5.00 (0.56–236.49)	NA	NA	0.50 (0.05–3.49)	1.50 (0.17–17.96)	3.00 (0.54–30.39)	1.00 (0.01–78.50)	NA	1.89 (1.06–3.50)
PE
2019	0	1	0	0	0	0	0	0	1	0	0	0	2
2020	2	0	0	2	2	0	1	0	1	1	1	1	11
2021	0	3	1	0	0	0	0	1	0	0	1	1	7
IRR^a (95% CI)	NA	NA	NA	NA	NA	NA	NA	NA	1.00 (0.01–78.50)	NA	NA	NA	5.50 (1.20–51.07)
IRR^b (95% CI)	NA	3.00 (0.24–157.49)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	3.50 (0.67–34.53)
HF
2019	22	17	14	8	10	9	9	4	8	1	10	10	122
2020	24	10	17	27	26	12	7	26	8	11	21	47	236
2021	78	39	31	54	57	19	17	44	31	29	31	35	465
IRR^a (95% CI)	1.09 (0.59–2.04)	0.59 (0.24–1.36)	1.21 (0.56–2.66)	3.38 (1.49–8.60)	2.60 (1.21–6.04)	1.33 (0.52–3.58)	0.78 (0.25–2.35)	6.50 (2.26–25.63)	1.00 (0.33–3.06)	11.00 (1.60–473.47)	2.10 (0.95–4.99)	4.70 (2.34–10.43)	1.93 (1.55–2.43)
IRR^b (95% CI)	3.55 (2.19–5.98)	2.29 (1.27–4.32)	2.21 (1.14–4.50)	6.75 (3.19–16.42)	5.70 (2.88–12.52)	2.11 (0.91–5.30)	1.89 (0.80–4.81)	11.00 (4.00–42.15)	3.88 (1.74–9.76)	29.00 (4.81–1,184.44)	3.10 (1.48–7.09)	3.50 (1.70–7.92)	3.81 (3.12–4.69)

^aIRR is for 2020 vs. 2019. ^bIRR is for 2021 vs. 2019. NA, not assessable. Other abbreviations as in Table 1.

The numbers of deaths among emergency patients hospitalized for cardiocerebrovascular diseases are shown in Table 3. There were no significant differences in the numbers of death from any of the cardiocerebrovascular diseases in 2021 and 2020 compared with 2019.

Table 3. Number of Deaths Among Emergency Patients Hospitalized for Cardiocerebrovascular Diseases by Month and Year in Osaka, Japan

Cardiocerebrovascular disease	January	February	March	April	May	June	July	August	September	October	November	December	Total
AMI
2019	23	21	20	18	13	16	13	13	16	8	27	20	208
2020	22	23	18	11	12	20	13	20	11	21	14	20	205
2021	18	24	13	17	15	12	14	10	13	24	9	17	186
IRR^a (95% CI)	0.96 (0.51–1.80)	1.10 (0.58–2.08)	0.90 (0.45–1.79)	0.61 (0.26–1.37)	0.92 (0.38–2.19)	1.25 (0.62–2.58)	1.00 (0.43–2.34)	1.54 (0.73–3.37)	0.69 (0.29–1.58)	2.63 (1.12–6.85)	0.52 (0.25–1.02)	1.00 (0.51–1.96)	0.99 (0.81–1.20)
IRR^b (95% CI)	0.78 (0.40–1.52)	1.14 (0.61–2.16)	0.65 (0.30–1.37)	0.94 (0.46–1.94)	1.15 (0.51–2.63)	0.75 (0.32–1.69)	1.08 (0.47–2.49)	0.77 (0.30–1.90)	0.81 (0.36–1.80)	3.00 (1.30–7.72)	0.33 (0.14–0.73)	0.85 (0.42–1.71)	0.89 (0.73–1.10)
Cerebral infarction
2019	35	29	29	16	20	28	13	17	25	25	22	27	286
2020	18	17	16	22	23	21	16	23	12	21	25	27	241
2021	40	17	35	28	20	21	27	19	20	25	19	36	307
IRR^a (95% CI)	0.51 (0.27–0.93)	0.59 (0.30–1.10)	0.55 (0.28–1.05)	1.38 (0.69–2.80)	1.15 (0.60–2.21)	0.75 (0.40–1.37)	1.23 (0.56–2.78)	1.35 (0.69–2.70)	0.48 (0.22–0.99)	0.84 (0.45–1.56)	1.14 (0.61–2.11)	1.00 (0.56–1.77)	0.84 (0.71–1.00)
IRR^b (95% CI)	1.14 (0.71–1.85)	0.59 (0.30–1.10)	1.21 (0.72–2.05)	1.75 (0.91–3.46)	1.00 (0.51–1.96)	0.75 (0.40–1.37)	2.08 (1.04–4.38)	1.12 (0.55–2.29)	0.80 (0.42–1.50)	1.00 (0.55–1.81)	0.86 (0.44–1.67)	1.33 (0.79–2.28)	1.07 (0.91–1.27)
IH
2019	43	34	40	34	25	32	31	28	24	34	44	29	398
2020	42	47	32	42	38	25	25	23	25	35	38	53	425
2021	48	27	31	27	30	28	27	19	32	43	27	46	385
IRR^a (95% CI)	0.98 (0.62–1.53)	1.38 (0.87–2.22)	0.80 (0.49–1.31)	1.24 (0.77–2.00)	1.52 (0.89–2.63)	0.78 (0.44–1.36)	0.81 (0.46–1.41)	0.82 (0.45–1.48)	1.04 (0.57–1.90)	1.03 (0.62–1.70)	0.86 (0.54–1.36)	1.83 (1.14–2.98)	1.07 (0.93–1.23)
IRR^b (95% CI)	1.12 (0.72–1.73)	0.79 (0.46–1.36)	0.78 (0.47–1.27)	0.79 (0.46–1.36)	1.20 (0.68–2.13)	0.88 (0.51–1.50)	0.87 (0.50–1.51)	0.68 (0.36–1.26)	1.33 (0.76–2.37)	1.26 (0.79–2.04)	0.61 (0.37–1.01)	1.59 (0.98–2.62)	0.97 (0.84–1.12)
SAH
2019	19	19	19	17	13	14	12	13	14	15	21	19	195
2020	19	21	17	22	14	14	14	7	16	23	11	17	195
2021	16	20	20	13	13	13	14	16	13	22	15	19	194
IRR^a (95% CI)	1.00 (0.50–2.00)	1.11 (0.57–2.17)	0.89 (0.44–1.82)	1.29 (0.66–2.60)	1.08 (0.47–2.49)	1.00 (0.44–2.26)	1.17 (0.50–2.76)	0.54 (0.18–1.45)	1.14 (0.52–2.53)	1.53 (0.77–3.16)	0.52 (0.23–1.14)	0.89 (0.44–1.82)	1.00 (0.82–1.23)
IRR^b (95% CI)	0.84 (0.41–1.73)	1.05 (0.53–2.08)	1.05 (0.53–2.08)	0.76 (0.34–1.67)	1.00 (0.43–2.34)	0.93 (0.40–2.13)	1.17 (0.50–2.76)	1.23 (0.56–2.78)	0.93 (0.40–2.13)	1.47 (0.73–3.04)	0.71 (0.34–1.45)	1.00 (0.50–2.00)	0.99 (0.81–1.22)
Aortic aneurysm and dissection
2019	20	10	17	6	16	8	5	7	10	17	18	22	156
2020	11	16	9	11	9	10	7	5	13	14	8	17	130
2021	19	15	12	18	9	11	12	8	15	15	14	20	168
IRR^a (95% CI)	0.55 (0.24–1.20)	1.60 (0.68–3.94)	0.53 (0.21–1.26)	1.83 (0.62–6.04)	0.56 (0.22–1.35)	1.25 (0.44–3.64)	1.40 (0.38–5.59)	0.71 (0.18–2.61)	1.30 (0.53–3.31)	0.82 (0.38–1.78)	0.44 (0.17–1.07)	0.77 (0.39–1.52)	0.83 (0.66–1.06)
IRR^b (95% CI)	0.95 (0.48–1.88)	1.50 (0.63–3.73)	0.71 (0.31–1.57)	3.00 (1.14–9.23)	0.56 (0.22–1.35)	1.38 (0.50–3.94)	2.40 (0.79–8.70)	1.14 (0.36–3.70)	1.50 (0.63–3.73)	0.88 (0.41–1.88)	0.78 (0.36–1.66)	0.91 (0.47–1.75)	1.08 (0.86–1.35)
PE
2019	2	3	0	2	4	1	0	0	1	1	3	3	20
2020	2	6	0	0	3	1	2	0	2	3	2	4	25
2021	6	3	2	1	0	1	2	0	2	4	0	1	22
IRR^a (95% CI)	1.00 (0.07–13.80)	2.00 (0.43–12.36)	NA	NA	0.75 (0.11–4.43)	1.00 (0.01–78.50)	NA	NA	2.00 (0.10–117.99)	3.00 (0.24–157.49)	0.67 (0.06–5.82)	1.33 (0.23–9.10)	1.25 (0.67–2.37)
IRR^b (95% CI)	3.00 (0.54–30.39)	1.00 (0.13–7.47)	NA	0.50 (0.01–9.60)	NA	1.00 (0.01–78.50)	NA	NA	2.00 (0.10–117.99)	4.00 (0.40–196.99)	NA	0.33 (0.01–4.15)	1.10 (0.57–2.12)
HF
2019	59	43	42	43	53	37	31	43	30	42	43	52	518
2020	71	58	70	35	32	28	30	20	44	31	48	60	527
2021	72	45	52	46	41	30	26	40	40	45	48	70	555
IRR^a (95% CI)	1.20 (0.84–1.73)	1.35 (0.89–2.05)	1.67 (1.12–2.50)	0.81 (0.51–1.30)	0.60 (0.38–0.95)	0.76 (0.45–1.27)	0.97 (0.57–1.65)	0.47 (0.26–0.81)	1.47 (0.90–2.42)	0.74 (0.45–1.20)	1.12 (0.72–1.73)	1.15 (0.78–1.71)	1.02 (0.90–1.15)
IRR^b (95% CI)	1.22 (0.85–1.75)	1.05 (0.67–1.63)	1.24 (0.81–1.91)	1.07 (0.69–1.66)	0.77 (0.50–1.19)	0.81 (0.48–1.35)	0.84 (0.48–1.46)	0.93 (0.59–1.47)	1.33 (0.81–2.22)	1.07 (0.69–1.67)	1.12 (0.72–1.73)	1.35 (0.93–1.97)	1.07 (0.95–1.21)

^aIRR is for 2020 vs. 2019. ^bIRR is for 2021 vs. 2019. NA, not assessable. Other abbreviations as in Table 1.

Discussion

The present study showed almost no differences in the numbers of hospitalized emergency patients or their deaths from cardiocerebrovascular diseases in Osaka Prefecture from 2019 to 2021; however, the number of difficulties in obtaining patient acceptance by hospitals of patients with each disease increased in 2020 and 2021 compared with 2019. Our findings from the population-based ORION data could be useful to improve future plans for the Emergency Medical Service system in Japan.

In Europe, the number of admissions to acute cardiology departments decreased by ≈30% for acute coronary syndrome (ACS) and acute HF, but there was no difference for PE in 2020 compared with 2019.⁴ A narrative review of emergency department management showed that the number of stroke cases decreased by ≈30%, and there was no difference in the mortality rate of stroke and ST-segment MI between the pre-pandemic and pandemic periods.⁵ In Osaka, there was almost no difference in the numbers of cases and deaths for any of the cardiocerebrovascular diseases, which suggested that the COVID-19 pandemic had little effect on the transport of emergency patients with cardiocerebrovascular diseases to hospital emergency departments. In Tokyo, the number of admissions for all emergency cardiovascular diseases reduced in 2020 and the in-hospital mortality rate remained the same in 2020 as in the pre-pandemic period.⁶ The reasons for the difference in the number changes of hospitalized patients with emergency cardiovascular diseases between Osaka and Tokyo are unclear, and regional differences in the impact of the COVID-19 pandemic on patients with cardiovascular diseases transported to emergency departments should be evaluated in the future.

In contrast, the number of difficulties in obtaining patient acceptance by hospitals increased for all of the cardiocerebrovascular diseases, and especially for HF, in 2021. This might be explained partially by the fact that HF presents symptoms similar to those of COVID-19 such as dyspnea and cough,⁷ which had a significant impact on the ability of the Emergency Medical Service (EMS) system to respond to the demand. As well, the EMS system was considered to be affected by the rapid increase in COVID-19 cases in 2021. The number of difficulties in obtaining patient acceptance by hospitals increased in the second year of the COVID-19 pandemic, which suggests a considerable impact on the acceptance of emergency patients hospitalized with non-COVID-19 diseases such as cardiocerebrovascular diseases, because the number of COVID-19 cases increased exceedingly from ≈30,000 in 2020 to 170,000 in 2021 in Osaka.¹ The COVID-19 pandemic badly affected the smooth transport of patients with cardiocerebrovascular diseases; however, the number of deaths after hospitalization of these patients did not increase, suggesting that the post-hospitalization treatments worked effectively. It was also reported that the COVID-19 outbreak did not appear to influence nonelective percutaneous coronary interventions for ACS cases in Kobe City, Japan, between February and May 2020, which supports our results.⁸

It has been suggested that the COVID-19 and COVID-19 mRNA vaccinations are associated with acute pericarditis and acute myocarditis.⁹^,¹⁰ In this study, we also evaluated acute pericarditis/acute myocarditis as COVID-19 vaccine-related diseases and found no significant increase in them.

The present study has some limitations. First, we had no information on disease-related severity or the in-hospital treatments of these emergency patients. Second, diagnosis was based on the ICD-10 codes. The relationship between the ICD code and clinical diagnosis of AMI and HF, the major diseases in this study, has been reported to be acceptable in hospitalized patients.¹¹ Third, we focused only on hospitalized patients for the incidence of cardiocerebrovascular diseases and prehospital deaths were not included in our analyses. However, the large sample size, and the population-based design of the database should minimize various biases of observational studies when revealing the epidemiology and outcome of emergency patients hospitalized with cardiocerebrovascular diseases in Japan.

In conclusion, the present ORION-based study revealed almost no differences in the numbers of emergency patients hospitalized with cardiocerebrovascular diseases or their deaths after hospitalization in Osaka Prefecture from 2019 to 2021.

Acknowledgments

We are deeply indebted to all of the EMS personnel and concerned physicians in Osaka Prefecture and to the Osaka Medical Association for their indispensable cooperation and support. This article was supported by the Osaka University Center of Medical Data Science and Advanced Clinical Epidemiology Investigator’s Research Project, which provided insight and expertise for our research, and by the Fire and Disaster Prevention Technologies Program (Grant no. 21584490).

Disclosures

Authors declare no Conflicts of Interest for this article.

IRB Information

This study was approved by the Ethics Committee of the Osaka University Graduate School of Medicine (No. 15003).

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