Decrease in ST-segment elevation myocardial infarction admissions in Catalonia during the COVID-19 pandemic

To the Editor,

On February 2020, the coronavirus disease of 2019 (COVID-19) rapidly spread throughout Europe. Due to the lack of pharmacological treatment or vaccine, governments adopted measures called social distancing to reduce the peak intensity of the epidemic. In Spain, the government issued a decree declaring a state of alarm on 14 March, 2020.

Timely reperfusion therapy by primary percutaneous coronary intervention (pPCI) is recommended for patients with ST-segment elevation myocardial infarction (STEMI)¹ and its benefit is time-dependent, with longer delays associated with worse outcomes. A recent survey of Spanish STEMI networks reported a reduction in pPCI procedures during the COVID-19 pandemic.² We aimed to assess the reduction in STEMI admissions and changes in patient characteristics, delay times and early mortality during the first weeks of the COVID-19 pandemic in Catalonia.

In Catalonia, a Spanish region with 7.6 million inhabitants, acute care for patients with STEMI is organized through a regional network of 10 pPCI hospitals.

The AMI code registry collects data from all attended STEMI patients. The registry belongs to the health department of the Catalan government and its completion is compulsory and periodically audited. The database conforms to ethical and legal requirements for research purposes, and all study procedures are conducted in accordance with the ethical standards of the Helsinki Declaration.

All patients with a confirmed STEMI from 1 March to 19 April, 2020, were compared with patients attended within the same dates in 2019.

Delay times were defined according to the European Guidelines.¹ Patient delay was defined as time from symptom onset to first medical contact. System delay as time from first contact to reperfusion therapy. Ischemia time as time from symptom onset to reperfusion therapy. Delay times were stratified by site of first medical contact.

Admission rates were estimated with Poisson regression models with time (days) as a continuous variable. Categorical variables are expressed as number and percentage and were compared with the chi-square test. Continuous variables are expressed as mean ± standard deviation and were compared with the Student t test. Time intervals are expressed as median [interquartile range] and were compared with the Kruskal-Wallis equality-of-populations rank test. Mortality at 10 days after activation was estimated for all patients with available information about vital status (STEMI occurring between March 1 and April 10).

A total of 395 STEMI patients were admitted during the 2020 period and 524 during the same period in 2019. The mean number of daily admissions was 10.5 in 2019 and 7.9 in 2020 (incidence rate ratio, 0.75; 95% confidence interval, 0.66-0.86). In 2020, there was a significant 52% reduction in daily admissions from day 1 to day 50 (figure 1 ). There were few differences between the groups (table 1 ).

Figure 1.

Daily rate of confirmed ST-segment elevation myocardial infarction admissions between March 1 and April 19 in 2019 (A) and 2020 (B).

Table 1.

Characteristics, delay times and outcomes of patients with confirmed ST-segment elevation acute myocardial infarction

	Valid n	2019	Valid n	2020	P
Female sex	524	109 (20.8)	395	78 (19.8)	.694
Age	524	63.4 ± 0.6	395	61.9 ± 0.7	.104
Age > 80 y	524	70 (13.4)	395	37 (9.4)	.062
Previous history of cardiovascular disease	524	73 (13.9)	395	64 (16.2)	.339
First assisted in hospital	524	232 (44.3)	395	145 (36.7)	.021
Sudden cardiac death	524	33 (6.3)	395	18 (4.6)	.254
Killip III-IV	501	53 (10.6)	387	43 (11.1)	.800
pPCI	519	425 (81.1)	394	337 (85.3)	.141
TIMI flow pre (no flow)	311	195 (62.7)	296	195 (65.9)	.414
TIMI flow post (normal)	309	298 (96.4)	292	279 (96)	.577
Delay time, median [q25-q75]
Patient delay
Attended by EMS	174	49 [24-90]	156	59 [29-132.5]	.059
Attended at hospitals	302	115 [45-280]	212	105 [52-284]	.898
System delay
Attended by EMS	141	80 [65-98]	133	83 [65-99]	.526
Attended at hospitals	266	94 [71-131]	196	103.5 [80.5-133]	.051
Total ischemia time
Attended by EMS	140	141 [115-193]	134	160.5 [125-231]	.095
Attended at hospital	265	239.5 [150-434]	192	239.5 [155–424]	.790
Door-to-balloon time	309	20 [15-27]	295	22 [18-29]	.041
10-day mortality	385	22 (5.7)	340	24 (7.1)	.459

EMS, emergency medical system; pPCI, primary percutaneous coronary intervention; TIMI, Thrombolysis in Myocardial Infarction.

Data are expressed as No. (%), mean ± standard deviation or median [interquartile range].

A similar reduction in STEMI admissions has already been reported in other settings.3, 4, 5 To our knowledge, this is the first study performed in Spain using individual patient data from a regional STEMI network. We observed a 50% reduction in STEMI admissions in 50 days and only slight differences in patient characteristics and delay times compared with patients admitted during the same period in 2019. Potential causes of this decrease in STEMI admissions include avoidance of medical care due to social distancing, STEMI underdiagnosis, and competing risk with the acquisition and severity of COVID-19, and warrant further investigation.