Impact of the COVID‐19 Pandemic on Coronary Heart Disease Admissions and Mortality in Mexico: An Ecological Study

ABSTRACT

Background and Aims

The COVID‐19 pandemic strained healthcare systems, affecting management of coronary heart disease (CHD). This study aims to assess the association between the COVID‐19 pandemic and in‐hospital case fatality rates, emergency department visits, and hospital admissions for CHD in Mexico.

Methods

We conducted an ecological study utilizing data from the Mexican Ministry of Health, spanning January 2018 to December 2021. CHD was defined using ICD‐10 codes I20–I25. We analyzed monthly and annual trends in CHD‐related emergency visits, hospital admissions, and in‐hospital case fatality rates (CFR), reporting results with 95% confidence intervals. The Kruskal–Wallis test assessed statistical significance. Segmented log‐linear regression models, with a fixed breakpoint in March 2020, were applied to monthly rates to estimate pre‐ and post‐break trends (Annual Percent Change, APC) and immediate level changes, using Newey–West standard errors.

Results

CHD emergency visits decreased by 9.8% in March 2020% and 60.8% in May 2020, with annual declines of 36.5% in 2020% and 32.3% in 2021 compared to pre‐pandemic levels. Hospital admissions fell by 31.6% in 2020% and 19.4% in 2021. Meanwhile, in‐hospital CFR rose from 8.6% before the pandemic to 12.6% in 2020% and 11.8% in 2021. A similar trend was observed in hospital discharges, where CFR increased from 13.75% pre‐pandemic to 16.63% in 2020% and 16.15% in 2021. Although hospital mortality was higher among women, men experienced greater reductions in emergency visits and larger relative increases in mortality. Segmented regression revealed an immediate drop of −54.6% in emergency visits and −50.8% in discharges, followed by annual post‐break increases of 2.09% and 2.88%, respectively.

Conclusion

The COVID‐19 pandemic in Mexico was associated with a decline in CHD hospital admissions alongside a significant rise in in‐hospital CFR, with segmented regression showing partial recovery following the initial drop, underscoring the need to strengthen healthcare resilience.

Summary

• What's Known: The COVID‐19 pandemic strained healthcare systems globally, including care for coronary heart disease (CHD).

• What's New: CHD emergency visits and hospital admissions in Mexico significantly declined during the pandemic, while in‐hospital case fatality rates increased.

• Clinical Implications: Healthcare systems must enhance resilience and adopt strategies, such as telemedicine, to ensure continuity of care for CHD patients during health crises.

1. Background

The COVID‐19 pandemic has been associated with widespread indirect impacts on healthcare systems worldwide [1, 2, 3]. Previous studies have reported a decrease in the number of patients admitted with coronary heart disease (CHD) not only in consultations and elective procedures but also in emergency admissions [2, 3, 4, 5]. This fact has raised questions about the prognosis of CHD patients, particularly those with acute coronary syndromes and strokes, since these events heavily depend on a prompt diagnosis and treatment [6]. Studies have shown that patients admitted with acute myocardial infarction during the first phase of the pandemic, experienced higher mortality and worse short‐term outcomes [1].

A recent meta‐analysis found that, during the pandemic, patients with ST‐segment elevation myocardial infarction (STEMI) experienced longer delays from symptom onset to the first medical contact, which were associated with a higher risk of complications and higher levels of high‐sensitivity troponin levels at admission [7]. Admissions for non‐ST‐segment elevation myocardial infarction (NSTEMI) also decreased during the pandemic, coinciding with an increased mortality risk [7]. Previous studies have shown that postponing elective procedures was associated with an increase in emergency surgeries for ruptured aortic aneurysms and acute aortic dissections [8].

To our knowledge, no study has estimated the changes in hospital discharges and in‐hospital mortality for CHD in Mexico, a middle‐income country where the CHD epidemic is still in its early stages and mortality rates continue to rise [9]. Using official national data from 2018 to 2021, our study fills this gap by offering a comprehensive analysis with a broader timeframe than most existing reports, which typically focus only on the pandemic's early months. This evidence is especially important for countries experiencing rapid epidemiological transitions, where interruptions in cardiovascular care could lead to disproportionately severe long‐term consequences. Our findings offer practical guidance for policymakers to strengthen health system preparedness and ensure continuity of essential cardiovascular services during future health crises. This information is critical to understanding the indirect effects of the COVID‐19 pandemic and to identifying potential targets for medical policy aimed at helping reduce the burden of CHD. Therefore, we aimed to investigate the association between the COVID‐19 pandemic period and in emergency and hospital admissions and in‐hospital lethality for CHD.

2. Methods

This ecological study, conducted in Mexico, used data from the Mexican Ministry of Health Information System for both emergency visits and hospital discharges from 2018 to 2021 [10]. Information was obtained using International Classification of Diseases, 10th Revision (ICD‐10) codes I20–I25, corresponding to ischemic heart diseases:

• I20 – Angina pectoris

• I21 – Acute myocardial infarction

• I22 – Subsequent myocardial infarction

• I23 – Certain current complications following acute myocardial infarction

• I24 – Other acute ischemic heart diseases

• I25 – Chronic ischemic heart disease

All codes were combined into a single “all coronary heart diseases” category. We also obtained information about in‐hospital mortality related to these admissions. The data were grouped by month and year separately for emergency visits and hospital discharges.

We calculated the monthly average of emergency visits and hospital discharges for 2018 and 2019 to serve as a baseline for the pre‐COVID‐19 period. These figures were then compared with the corresponding months in 2020 and 2021 to determine both monthly and annual percentage changes in emergency visits and hospital discharges.

In‐hospital case fatality rates were calculated by dividing the number of reported deaths by the total number of patients with CHD in the respective month and year for emergency and hospital discharges. We also obtained the pre‐COVID monthly average case fatality rates and compared these baseline rates with the corresponding monthly lethality rates observed in 2020 and 2021. For these comparisons, we calculated both the monthly and annual percentage changes along with their corresponding 95% confidence intervals as measures of effect size and the reliability of our estimates [11].

We performed the Kruskal–Wallis test [12] to compare the monthly distributions of the reference period with those of 2020 and 2021 for both emergency visits/hospital discharges and case fatality rates. P‐values were reported alongside effect size estimates and 95% confidence intervals. All tests were two‐sided, and statistical significance was set a priori at α = 0.05.

Temporal trends in monthly CHD‐related emergency visits and hospital discharges were evaluated using segmented (piecewise) log‐linear regression models, with a fixed breakpoint set at March 2020, corresponding to the onset of the COVID‐19 pandemic in Mexico. The models included: (1) a pre‐break slope (time, in months, from January 2018), (2) an indicator term for the break month (to estimate the immediate level change), and (3) a post‐break slope (time since March 2020). Analyses were performed on the natural logarithm of monthly rates per 100,000 population, with national population estimates used as denominators to standardize the data. Pre‐ and post‐break slopes were expressed as Annual Percent Change (APC) values, calculated as (exp(β)−1)×100 with 95% confidence intervals (CIs). The immediate change at the breakpoint was calculated from the break coefficient as (exp(β_break)−1)×100. Models were fitted using Newey–West standard errors with a maximum lag of 2 months to account for autocorrelation. Separate models were estimated for emergency visits and hospital discharges. Additionally, sensitivity analyses were conducted using ordinary least squares (OLS) with robust standard errors and Prais–Winsten regression with AR(1) errors.

Given the ecological and observational design, all estimates reflect population‐level temporal associations and should not be interpreted as individual‐level causal effects.

All statistical analyses were conducted using Stata 18 BE (StataCorp, College Station, TX, USA).

3. Results

Table 1 presents the total number of emergencies and hospitalization discharges for CHD. Between 2018 and 2019, annual emergency visits rose by 5.6% (95% CI: 3.1 to 8.1); the first notable decline during the pandemic period was observed in March 2020 when emergency visits dropped by 9.8% (95% CI: −14.9 to −4.7) compared to the average for the two previous years. Emergency visits dropped to their lower levels in May 2020, with only 568 patients, representing a 60.8% decrease (95% CI: −63.5 to −58.1) compared with the reference average. The annual percentage change in emergency visits was −36.5% (95% CI: −40.3 to −32.7) in 2020 and −32.3% (95% CI: −36.4 to −28.2) in 2021, compared to the 2018–2019 average.

Table 1.

Emergency visits for CHD in Mexico per month 2018–2021.

Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	TOTAL	p‐value*
A) Emergency visits ( n )
2018	1522	1313	1451	1413	1390	1322	1400	1472	1379	1438	1352	1288	16740
2019	1675	1503	1596	1448	1508	1431	1517	1467	1391	1401	1458	1280	17675
2020	1602	1534	1374	732	568	556	597	655	737	909	853	816	10933
2021	700	734	950	856	1049	1137	1092	935	992	1008	1028	1163	11644
Reference (2018–2019)~	1599 ± 108.2	1408 ± 134.3	1524 ± 102.5	1431 ± 24.7	1449 ± 8.5	1377 ± 77.1	1459 ± 82.7	1470 ± 3.5	1385 ± 8.5	1420 ± 26.2	1405 ± 75.0	1284 ± 5.7	17208
% Change 2020'	0.2% (–7.0, 7.4)	8.9% (–1.6, 19.4)	−9.8% (–17.3, –2.3)	−48.8% (–52.7, –44.9)	−60.8% (–62.0, –59.6)	−59.6% (–64.5, –54.7)	−59.1% (–64.2, –54.0)	−55.4% (–56.6, –54.2)	−46.8% (–49.6, –44.0)	−36.0% (–39.2, –32.8)	−39.3% (–44.4, –34.2)	−36.4% (–38.0, –34.8)	−37.4% (–51.8, –23.0)	< 0.001
% Change 2021'	−56.2% (–59.1, –53.3)	−47.9% (–54.6, –41.2)	−37.6% (–42.7, –32.5)	−40.2% (–43.7, –36.7)	−27.6% (–28.7, –26.5)	−17.4% (–21.9, –12.9)	−25.1% (–29.8, –20.4)	−36.4% (–37.4, –35.4)	−28.4% (–30.6, –26.2)	−29.0% (–32.1, –25.9)	−26.8% (–31.4, –22.2)	−9.4% (–10.1, –8.7)	−33.3% (–40.3, –26.3)	< 0.001
B) In‐hospital case fatality rate (%)
2018	10.1	9.2	7.3	6.7	8.9	9.2	8.6	8.1	7.9	8.2	8.4	12	8.7
2019	10	9.4	7.8	8.8	7.1	7.6	7.8	8.3	7.5	8.6	9.3	9.3	8.5
2020	9.4	8.6	8.7	12.4	20.1	18	15.1	15.9	13.2	12.2	14.7	16.9	12.6
2021	19.4	13.4	12.2	10.7	12.3	11.5	11.7	10.9	11.2	10.7	9.8	10.8	11.8
Reference (2018–2019)~	10.05 ± 0.07	9.30 ± 0.14	7.55 ± 0.35	7.75 ± 1.48	8.00 ± 1.27	8.40 ± 1.13	8.20 ± 0.57	8.20 ± 0.14	7.70 ± 0.28	8.40 ± 0.28	8.85 ± 0.64	10.65 ± 1.91	8.71
% Change 2020'	−6.0% (–11.8, –0.2)	−7.5% (–13.5, –1.5)	+15.9% (7.4, 24.4)	+59.0% (54.0, 64.0)	+151.3% (148.1, 154.5)	+114.3% (111.0, 117.6)	+84.1% (80.9, 87.3)	+94.1% (91.2, 97.0)	+71.4% (68.4, 74.4)	+45.2% (42.3, 48.1)	+65.2% (62.0, 68.4)	+59.4% (55.9, 62.9)	+46.5% (33.8, 59.2)	< 0.001
% Change 2021'	+94.0% (90.1, 97.9)	+44.1% (40.0, 48.2)	+62.7% (58.0, 67.4)	+37.2% (34.0, 40.4)	+53.8% (51.0, 56.6)	+36.9% (33.9, 39.9)	+42.7% (39.9, 45.5)	+32.9% (30.1, 35.7)	+45.5% (42.7, 48.3)	+27.4% (24.7, 30.1)	+10.1% (7.4, 12.8)	+1.9% (–0.6, 4.4)	+37.2% (25.0, 49.4)	< 0.001

Note: ´* Kruskal‐Wallis test comparing reference distribution with 2020 or 2021, ~ Reference: Average 2018–2019, ´ The percentage change value in the TOTAL column represents the annual mean percentage change vs reference, with its 95% CI. The remaining values are monthly percentage changes vs reference with 95% CI.

Figure 1 shows the monthly number of emergency visits from 2018 through 2021. Following a steep decline in early 2020, visits partially recovered and then gradually rebounded but stayed below pre‐pandemic levels until late 2021, when they nearly returned to baseline values.

Figure 1.

Monthly number of emergency visits for coronary heart disease (CHD) and corresponding in‐hospital case fatality rates (CFR) in Mexico, 2018–2021. CHD was defined using ICD‐10 codes I20–I25. The first (upper) panel shows the number of emergency visits, and the second (lower) panel shows the corresponding monthly CFR. Lines in different colors represent each study year (2018, 2019, 2020, and 2021), as indicated in the figure legend. X‐axis shows months (2, 4, 6, 8, 10), and Y‐axis shows counts (visits) or percentages (CFR). Data source: Mexican Ministry of Health Information System.

In the pre‐COVID years, the in‐hospital case fatality rate in emergencies was 8.6%; in 2020, it was 12.6%, a 46.4% increase (95% CI: 39.5 to 53.3) over the reference (Table 2). In 2021, the rate was 11.8%, representing a 37.9% higher rate (95% CI: 30.2 to 45.6). Notably, case fatality rates were consistently higher than the reference since March 2020 and only normalized in December 2021.

Table 2.

Hospital discharges for CHD in Mexico per month 2018–2021.

Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	TOTAL	p‐value*
A) Hospital discharges ( n )
2018	1139	1064	1168	1053	1098	1090	1209	1047	1010	1199	1106	1079	13262
2019	1084	981	1061	1070	1038	974	1045	1044	999	1041	1037	1000	12374
2020	1263	1186	1165	582	476	418	475	530	643	782	618	630	8768	< 0.01
2021	587	574	813	749	905	982	1030	797	865	972	1001	1054	10329	< 0.01
Reference (2018–2019)~	1111.5 ± 38.9	1022.5 ± 58.7	1114.5 ± 75.6	1061.5 ± 12.0	1068.0 ± 42.4	1032.0 ± 81.8	1127.0 ± 116.0	1045.5 ± 2.1	1004.5 ± 7.8	1120.0 ± 112.1	1071.5 ± 48.8	1039.5 ± 55.7	12818	—
% Change 2020′	+13.6% (8.7, 18.5)	+16.0% (11.1, 20.9)	+4.5% (–1.0, 10.0)	–45.2% (–47.9, –42.5)	–55.4% (–57.7, –53.1)	–59.5% (–61.8, –57.2)	–57.9% (–60.5, –55.3)	–49.3% (–51.4, –47.2)	–36.0% (–38.7, –33.3)	–30.2% (–32.8, –27.6)	–42.3% (–44.9, –39.7)	–39.4% (–41.9, –36.9)	–31.6% (–37.4, –25.8)	< 0.01
% Change 2021′	–47.2% (–49.9, –44.5)	–43.9% (–46.5, –41.3)	–27.1% (–29.6, –24.6)	–29.4% (–32.0, –26.8)	–15.3% (–17.6, –13.0)	–4.8% (–6.9, –2.7)	–8.6% (–10.9, –6.3)	–23.8% (–26.2, –21.4)	–13.9% (–16.1, –11.7)	–13.2% (–15.5, –10.9)	–6.6% (–8.9, –4.3)	+1.4% (–0.7, 3.5)	–19.4% (–23.8, –15.0)	< 0.01
B) In‐hospital case fatality rate (%)
2018	15.01	15.23	13.27	11.02	12.2	13.39	11.41	13.56	11.88	13.01	14.01	13.62	13.14
2019	16.24	15.09	16.4	13.55	14.93	13.35	13.21	12.64	15.52	13.74	13.31	14.4	14.37
2020	16.79	15.26	13.91	13.06	24.37	23.44	18.32	17.17	18.35	13.55	16.5	17.3	16.63	< 0.01
2021	24.02	18.12	14.88	16.82	14.81	15.07	14.95	16.06	17.8	15.74	14.79	14.9	16.15	< 0.01
Reference (2018–2019)~	15.63 ± 0.87	15.16 ± 0.10	14.84 ± 2.21	12.29 ± 1.79	13.57 ± 1.93	13.37 ± 0.03	12.31 ± 1.27	13.10 ± 0.46	13.70 ± 2.57	13.38 ± 0.52	13.66 ± 0.50	14.01 ± 0.55	13.75	—
% Change 2020′	+7.43% (3.4, 11.5)	+0.69% (–3.0, 4.4)	–6.27% (–10.0, –2.5)	+6.31% (2.7, 9.9)	+79.61% (76.4, 82.8)	+75.35% (72.1, 78.6)	+48.79% (45.4, 52.2)	+31.04% (27.9, 34.2)	+33.97% (30.9, 37.0)	+1.35% (–2.1, 4.8)	+20.82% (17.6, 24.0)	+23.48% (20.0, 26.9)	+20.9% (14.1, 27.7)	< 0.01
% Change 2021′	+53.7% (50.3, 57.1)	+19.5% (15.9, 23.1)	+0.3% (–3.2, 3.8)	+36.9% (33.4, 40.4)	+9.1% (6.0, 12.2)	+12.7% (9.5, 15.9)	+21.5% (18.3, 24.7)	+22.6% (19.5, 25.7)	+30.0% (26.8, 33.2)	+17.7% (14.4, 21.0)	+8.2% (5.0, 11.4)	+6.3% (3.0, 9.6)	+17.4% (11.9, 22.9)	< 0.01

Note: ´* Kruskal‐Wallis test comparing reference distribution with 2020 or 2021. ~ Reference: Average 2018–2019. ´ The percentage change value in the TOTAL column represents the annual mean percentage change vs reference, with its 95% CI. The remaining values are monthly percentage changes vs reference with 95% CI.

Regarding sex differences, the number of emergency patients was consistently higher among men (61%) than among women (Figure 1). However, the observed drop in emergency visits was more pronounced in women. Specifically, emergency visits of male patients decreased by 36% (95% CI: −39.8 to −32.2) in 2020 and by 31% (95% CI: −35.0 to −27.0) in 2021, versus 37% (95% CI: −40.8 to −33.2) and 35% (95% CI: −39.0 to −31.0) in women. Pre‐COVID in‐hospital case fatality rates were 8.08% for men and 8.9% for women. In 2020, fatality rates increased by 51.0% (95% CI: 44.2 to 57.8) among men and by 49.0% (95% CI: 42.1 to 55.9) among women. In 2021, the increases were 34.0% (95% CI: 27.3 to 40.7) for men and 55.0% (95% CI: 48.3 to 61.7) for women.

During the reference years, the average annual number of hospital discharges was 12,818. This figure declined by 31.6% (95% CI: −37.4 to −25.8) in 2020% and 19.4% (95% CI: −23.8 to −15.0) in 2021 (Table 2), reflecting a substantial reduction in hospital admissions during the pandemic period. Discharges exhibited a pattern similar to emergency visits, with the steepest decline occurring in June 2020 (−59.5%; 95% CI: −61.8 to −57.2). Recovery began late in 2021, ultimately surpassing the reference level by 1.4% in December.

The average in‐hospital lethality rate before COVID was 13.75% (Table 2). However, the lethality rates in 2020 and 2021 were 16.63% and 16.15%, respectively, representing an increase of 20.92% (95% CI: 18.1 to 23.7) in 2020% and 17.4% (95% CI: 14.5 to 20.3) relative to the reference period.

Men accounted for 66% of hospital discharges in 2018–2019, averaging 8,470 discharges per year compared to 4,347 for women (Figure 2). In 2020, discharges dropped by 31.4% (95% CI: −35.6 to −27.2) among men and 31.9% (95% CI: −36.2 to −27.6) among women. The reductions in 2021 were 16.0% (95% CI: −19.9 to −12.1) for men and 26.0% (95% CI: −30.4 to −21.6) for women. The baseline in‐hospital case fatality rate was 11.77% for men and 17.6% for women. In men, it increased by 26.1% in 2020% and 22.0% in 2021; in women, by 14.7% and 14.0%. Despite these changes, fatality remained consistently higher in women, reaching 20.1% in 2020% and 20.0% in 2021, compared to 14.8% and 14.4% in men.

Figure 2.

Monthly number of hospital discharges for coronary heart disease (CHD) and corresponding in‐hospital case fatality rates (CFR) in Mexico, 2018–2021. CHD was defined using ICD‐10 codes I20–I25. The first (upper) panel shows the number of hospital discharges, and the second (lower) panel shows the corresponding monthly CFR. Lines in different colors represent each study year (2018, 2019, 2020, and 2021), as indicated in the figure legend. X‐axis shows months (2, 4, 6, 8, 10), and Y‐axis shows counts (discharges) or percentages (CFR). Data source: Mexican Ministry of Health Information System.

Table 3 summarizes the results of segmented log‐linear regression analyzing monthly CHD emergency visits and hospital discharges in Mexico from January 2018 to December 2021. Prior to March 2020, emergency visits showed no significant change (0.17% per year; 95% CI −0.10 to 0.44; p = 0.21), while hospital discharges had a non‐significant decline (−0.19% per year; 95% CI −0.64 to 0.27; p = 0.41). At the pandemic onset in March 2020, both indicators experienced sharp declines: emergency visits dropped by 54.6% (95% CI − 66.0 to −37.9; p < 0.001) and hospital discharges fell by 50.8% (95% CI −65.1 to −31.4; p < 0.001). Following this breakpoint, both indicators demonstrated significant recovery trends, increasing annually by 2.09% (95% CI 0.03 to 4.12; p = 0.047) for emergency visits and 2.88% for discharges (95% CI 0.55 to 5.13; p = 0.016).

Table 3.

Segmented log‐linear regression models for monthly CHD emergency visits and hospital discharges, Mexico, January 2018–December 2021.

Outcome	Pre‐break APC % (95% CI)	p‐value	Immediate change at Mar 2020% (95% CI)	p‐value	Post‐break APC % (95% CI)	p‐value
Emergency visits	+0.17 (−0.10, +0.44)	0.212	−54.6 (−66.0, −37.9)	< 0.001	+2.09 (+0.03, +4.12)	0.047
Hospital discharges	−0.19 (−0.64, +0.27)	0.407	−50.8 (−65.1, −31.4)	< 0.001	+2.88 (+0.55, +5.13)	0.016

Note: Immediate change calculated from the break coefficient as (e^βbreak −1)×100. Estimates are based on log‐transformed monthly rates per 100,000 population, using national population estimates as denominators.

Abbreviation: APC = Annual Percent Change, estimated from monthly log‐rate trends.

Additional sensitivity analyses using OLS and Prais–Winsten models produce similar results. However, models adjusted for autocorrelation showed smaller immediate effects and, in some instances, post‐break trends that were not statistically significant (Supplementary Table S1).

4. Discussion

In this study, we analyzed the association between the COVID‐19 pandemic period and changes on emergency visits, hospital discharges, and in‐hospital case fatality rates. We found a substantial 36.5% decrease (95% CI: −40.3 to −32.7) in emergency visits and a 31.6% reduction (95% CI: −37.4 to −25.8) in hospital discharges in 2020 compared to previous years. Although both metrics showed some recovery in 2021, they remained below pre‐pandemic levels. Meanwhile, in‐hospital case fatality rates showed a significant increase, particularly for emergency visits, rising by 46.4% (95% CI: 39.5 to 53.3) compared to the reference period.

In addition, segmented log‐linear regression analysis revealed an immediate decline of −54.6% in emergency visits and −50.8% in hospital discharges at the onset of the pandemic (March 2020), followed by modest yet statistically significant increases (+2.09% and +2.88% per year, respectively). These patterns are consistent with a partial recovery over time, although volumes did not return to pre‐pandemic levels.

Previous studies have reported a decline in hospital admissions for acute syndromes, including STEMI, NSTEMI, and other acute ischemic heart diseases, during the COVID‐19 pandemic [2, 13, 14, 15]. A systematic review of 40 studies found a 28.1% decrease in hospital admissions for ACS compared with the same period in 2019, which is almost eight percentage points less than the decline observed in our emergency visits data [2]. However, most of the studies included in the review were conducted in high‐income countries, with only two from middle‐income countries in Asia. In Latin America, a multicenter study involving 18 centers across seven countries, including Mexico, reported declines in admissions for all types of strokes in most countries, but notably, no such decline was observed in Mexico [16]. This discrepancy may be related to the previous study focusing solely on acute stroke, and the analysis covered only from March to June 2020, whereas our study encompassed the entire period of 2020–2021, and included all months. Furthermore, the Mexican sample in that study was limited to 5 centers, while our study utilized comprehensive official national data.

Our findings reveal a statistically significant increase in the in‐hospital case fatality rate during 2020, with emergency visits rising to 12.6% representing a 46.4% increase (95% CI: 39.5 to 53.3), and hospital discharges increasing to 16.63%, a 20.92% rise (95% CI: 18.1 to 23.7). While the fatality rates observed in our study were higher than those reported in previous research, the relative magnitude of the increase during the pandemic period was even greater in some other countries [16, 17]. In the Latin American study on acute strokes, in‐hospital fatality rates increased from 4.9% to 9.7% [16], and although the fatality rate nearly doubled, it remained lower than the levels observed in Mexico. Furthermore, a study conducted in Brazil comparing data from the Private Health System between 2020 and the previous 2 years reported a greater impact compared to our study, showing a 26% reduction in coronary admission rates (95% CI: 22,30) alongside an increase in in‐hospital fatality rates from 3.6% (95% CI 3.2, 4.1) to 5.4% (95% CI: 4.5, 6.4) [17].

In addition, sex‐stratified analyses showed consistently higher in‐hospital case fatality rates among women compared with men, both before and during the pandemic period. This pattern is consistent with previous evidence from Mexico reporting higher in‐hospital mortality among women hospitalized for acute myocardial infarction prior to the COVID‐19 pandemic, suggesting that a higher baseline CFR among women is an expected finding rather than a pandemic‐specific anomaly [18]. Similar sex differences in short‐term hospital mortality following acute coronary events, including acute myocardial infarction and broader manifestations of coronary heart disease, have been documented in other populations, where women tend to experience worse in‐hospital outcomes despite a lower overall incidence of CHD [19, 20].

Several factors have been proposed to help interpret these differences. Women with acute coronary syndromes are more likely to be older at presentation, to have a higher burden of cardiometabolic comorbidities, and to present with atypical or less specific symptoms, which may delay recognition and timely treatment [18, 21]. In addition, multiple studies have documented longer pre‐hospital delays and a lower probability of receiving timely care after first medical contact among women, as well as lower use of invasive management strategies during acute coronary syndromes, patterns that have been associated with worse in‐hospital outcomes [21, 22, 23]. In this context, the larger relative increases in case fatality observed among women in 2021—despite smaller reductions in hospital admissions—may reflect a selective pattern in which women who did seek hospital care during later phases of the pandemic presented with more severe clinical profiles, potentially amplifying pre‐existing sex‐based disparities in outcomes without implying a higher underlying incidence of coronary heart disease.

To interpret the changes in CHD admission and fatality rates during the COVID‐19 pandemic, several hypotheses have been proposed. A key factor is patients' fear of contracting the virus, which has been reported to delay or avoid seeking medical care [13]. This behavior is consistent with widespread adherence to social distancing and stay‐at‐home recommendations and coinciding with reduced hospital admissions despite ongoing health needs [2]. The most pronounced decline in hospital admissions occurred during the early weeks of the pandemic. A UK study found fear of COVID‐19 infection as the main reason for patients avoiding hospitalization [24]. Additionally, some studies suggest that this hesitancy is greater in individuals with less severe symptoms [13, 25], which may have influenced mortality patterns by introducing a selection bias in which predominantly severe cases seek hospital care. In Mexico during 2020, 18.6% of the population reported having health needs, but only 82% of those individuals sought medical care; the main reasons for not seeking care were the perception that the condition was not severe (55%), lack of financial resources (12%), and fear of COVID‐19 infection (11%) [26].

Another potential explanation for the increase in hospital mortality is the possible role of underdiagnosis of COVID‐19 within the Mexican population and its implications for CHD patients. During the first months of the pandemic, limited testing capacity, combined with a high rate of asymptomatic infections, resulted in many cases going undetected. A nationally representative seroprevalence study found that 67% of individuals with SARS‐CoV‐2 antibodies were asymptomatic [27], suggesting that some CHD patients admitted to hospitals may have had concurrent or recent SARS‐CoV‐2 infection that went clinically unrecognized. Considering the well‐documented association between COVID‐19 and adverse cardiovascular outcomes ‐including pro‐inflammatory, thrombotic, and arrhythmias [13, 28, 29] ‐ these undiagnosed infections may have contributed in the increased in‐hospital mortality observed during the pandemic. This possibility also raises important methodological considerations regarding outcome classification, which are addressed below.

Another possible explanation for the observed reduction in hospitalization is the healthcare system's adaptation to the pandemic [13]. Overwhelmed healthcare facilities were associated with reductions in elective surgeries or deferrals of less urgent cases [13]. A previous study found reductions in essential health services in the Mexican Institute of Social Security (IMSS), the main healthcare provider for the Mexican Population [30]. At the onset of the pandemic, guidelines recommended limiting visits to healthcare facilities to emergencies only, resulting in the cancellation or rescheduling of most routine medical appointments [30]. Patients with well‐managed chronic diseases were eligible to receive refillable electronic prescriptions, while those with uncontrolled conditions were not provided with any options for routine monitoring [30]. Doubova et al. reported approximately a 30% decline in consultations for diabetes and hypertension—critical risk factors for CHD—with a corresponding increase in patients remaining uncontrolled; this figure likely underestimates the true extent of the problem [30]. These shifts in CHD risk factor management may have been associated with greater severity of cases requiring hospitalization, which could partly explain the rise in fatality rates.

It is plausible that these changes in healthcare utilization were associated with worse prognosis of CHD patients, including higher mortality and complications. Consequently, healthcare systems must implement strategies to adapt and restore patient trust. Roth et al., studied differences in cardiovascular (CVD) mortality during the COVID epidemic across different countries and found that while countries like Ecuador, Mexico, and Russia experienced increases in cardiovascular mortality (CVD), encompassing CHD, other nations maintained or reduced CVD deaths [31]. Several strategies have been proposed to mitigate the impact of the COVID‐19 pandemic. These include adopting telemedicine services to monitor patients through video calls; establishing mobile clinics that offer in‐home visits for patients requiring physical examinations; prioritizing patients with higher risk scores by utilizing smartphone applications to monitor heart rhythms; and employing smartwatches capable of detecting atrial fibrillation to some extent. To rebuild patient confidence, social media and newspapers can be used to foster trust in the healthcare system and educate people on critical topics such as myocardial infarctions, dyspnea, or heart failure [32].

Beyond the immediate reduction in admissions and the rise in case fatality, our findings reveal crucial clinical and health system challenges. Clinically, the increase in in‐hospital mortality underscores the need to ensure continuous early detection, rapid referral, and timely reperfusion therapy for CHD even during crises. Health systems should prioritize maintaining access to emergency cardiovascular care and critical procedures, such as percutaneous coronary intervention, to reduce morbidity and mortality, especially during crises. From a system perspective, the sustained decline in admissions during 2020–2021 highlights ongoing barriers to care and underscores the urgent need for contingency plans within national cardiovascular strategies. These plans should focus on decentralized diagnostics, effective risk communication, and improved coordination across care levels. Investments in digital health technologies, training non‐specialist providers, and enabling flexible resource allocation will be essential to ensure continuity of cardiovascular care during future emergencies.

As with any observational study, our research has limitations. Being an ecological study, it is based on aggregated population‐level data, which restricts the ability to draw individual‐level conclusions or establish causal relationships. This makes the study vulnerable to ecological fallacy, where assumptions made about individuals may not hold true based on group data. Additionally, the reliance on administrative data from the Mexican Ministry of Health could introduce potential biases or inaccuracies in reporting.

An additional limitation is the potential misclassification of causes of death during the COVID‐19 pandemic. Limited access to SARS‐CoV‐2 testing and diagnostic confirmation—particularly during the early phases of the pandemic—may have resulted in some deaths being coded as coronary heart disease among hospitalized patients with concurrent or recent, unrecognized COVID‐19. Given the well‐documented cardiovascular involvement of SARS‐CoV‐2 infection, such misclassification may have led to an overestimation of in‐hospital CHD case fatality rates during 2020–2021 and should be considered when interpreting our findings [27, 31].

Furthermore, we were unable to adjust for confounding factors such as comorbidities, healthcare access, or changes in medical treatments during the pandemic, all of which may have influenced the observed trends. Lastly, the findings are specific to Mexico and may not be directly applicable to other countries with different healthcare systems and COVID‐19 responses.

5. Conclusion

During the COVID‐19 pandemic in Mexico, a decrease in discharges for coronary heart disease patients was observed and coincided with a rise in in‐hospital case fatality rates. Healthcare systems may consider adopting targeted, practical strategies to rebuild patient trust and support continuous cardiovascular care during health crises. These strategies should include strengthening early detection and referral processes for CHD; ensuring uninterrupted access to vital cardiovascular interventions, such as percutaneous coronary interventions; and tackling ongoing obstacles to care that could influence the long‐term burden of CHD.

Contingency plans integrated into national cardiovascular strategies could encompass: (1) expanding telemedicine services for routine follow‐ups; (2) deploying mobile clinics and community‐based diagnostic units to overcome geographic and financial barriers; (3) launching targeted public awareness campaigns to encourage timely care‐seeking for acute symptoms; and (4) ensuring that essential cardiovascular procedures remain prioritized even during service disruptions. Despite some recovery following the initial decline, segmented regression analysis shows that service volumes had not returned to pre‐pandemic levels. Adapting to these evolving conditions through such targeted interventions may help improve patient outcomes and mitigate the long‐term consequences of future pandemics or emergencies on coronary health.

Author Contributions

Carmen Arroyo‐Quiroz: conceptualization, methodology, formal analysis, data curation, writing – original draft, writing – review and editing. Adriana Monroy: writing – review and editing, investigation. Silvestre Alavez: conceptualization, writing – original draft, writing – review and editing, supervision, project administration, validation.

Funding

The authors have nothing to report.

Ethics Statement

Ethical approval and informed consent were not required for this study because it used publicly available, de‐identified data from the Mexican Ministry of Health Information System, following local regulations and institutional guidelines. Public access to the database is available at: https://sinba.salud.gob.mx/CubosDinamicos.

Conflicts of Interest

The authors declare no conflicts of interest.

Transparency Statement

The lead author Carmen Arroyo‐Quiroz, Silvestre Alavez affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

Supporting information

Supporting File

Data Availability Statement

The dataset(s) supporting the conclusions of this article are publicly available in the Mexican Health Information System at the following link: https://sinba.salud.gob.mx/CubosDinamicos.