key: cord-0806757-r57oy7vk
authors: Chavez, Summer; Huebinger, Ryan; Chan, Hei Kit; Gill, Joseph; White, Lynn; Mendez, Donna; Jarvis, Jeffrey L.; Vithalani, Veer D.; Tannenbaum, Lloyd; Al-Araji, Rabab; Bobrow, Bentley
title: The impact of COVID-19 on incidence and outcomes from out-of-hospital cardiac arrest (OHCA) in Texas
date: 2022-04-13
journal: Am J Emerg Med
DOI: 10.1016/j.ajem.2022.04.006
sha: 1aaeab011c6ebc846e47a42a52151f4153ded3dd
doc_id: 806757
cord_uid: r57oy7vk

INTRODUCTION: Emerging research demonstrates lower rates of BCPR, public AED (PAD), worse outcomes, and higher incidence of OHCA during the COVID-19 pandemic. We aim to characterize the incidence of OHCA during the early pandemic period and the subsequent long-term period while describing changes in OHCA outcomes and survival. METHODS: We analyzed adult OHCAs in Texas from the Cardiac Arrest Registry to Enhance Survival (CARES) during March 11–December 31 of 2019 and 2020. We stratified cases into pre-COVID-19 and COVID-19 periods. Our prehospital outcomes were bystander cardiopulmonary resuscitation (BCPR), public AED use (PAD), sustained ROSC, and prehospital termination of resuscitation (TOR). Our hospital survival outcomes were survival to hospital admission, survival to hospital discharge, good neurological outcomes (CPC Score of 1 or 2) and Utstein bystander survival. We created a mixed effects logistic regression model analyzing the association between the pandemic on outcomes, using EMS agency as the random intercept. RESULTS: There were 3619 OHCAs (45.0% of overall study population) in 2019 compared to 4418 (55.0% of overall study population) in 2020. Rates of BCPR (46.2% in 2019 to 42.2% in 2020, P < 0.01) and PAD (13.0% to 7.3%, p < 0.01) decreased. Patient survival to hospital admission decreased from 27.2% in 2019 to 21.0% in 2020 (p < 0.01) and survival to hospital discharge decreased from 10.0% in 2019 to 7.4% in 2020 (p < 0.01). OHCA patients were less likely to receive PAD (aOR = 0.5, 95% CI [0.4, 0.8]) and the odds of field termination increased (aOR = 1.5, 95% CI [1.4, 1.7]). CONCLUSIONS: Our study adds state-wide evidence to the national phenomenon of long-term increased OHCA incidence during COVID-19, worsening rates of BCPR, PAD use and survival outcomes.

Out-of-hospital cardiac arrest (OHCA) is a leading cause of death in the United States, accounting for more than 300,000 occurrences per year [1, 2] . Decades of research has shown few interventions that consistently improve outcomes--early initiation of bystander cardiopulmonary resuscitation (BCPR) and automated external defibrillator use (AED)--yet survival rates have remained relatively constant (<10%) [ [3] , [4] , [5] , [6] ]. Prior research estimates that close to half of OHCA patients receive BCPR while public AED rates hover around 9-12% [ [7] , [8] , [9] , [10] ]. As such, these are high-yield targets for public health efforts to increase interventions that are key to improving OHCA survival rates.

Emerging studies are beginning to show the tremendous impact of the SARS-CoV-2 pandemic (COVID-19) on OHCA outcomes. These previous studies demonstrate lower rates of BCPR (8.94% decrease from 2020 to 2019) and public AED (PAD) usage, corresponding to lower rates of sustained return of spontaneous circulation (ROSC) (23.0% in 2020 versus 29.8% in 2019; adjusted rate ratio, 0.82 [95% CI, 0.78-0.87]; P < .001), lower survival to hospital discharge (6.6% in 2020 versus 9.8% in 2020; adjusted RR, 0.83 [95% CI, 0.69-1.00]; P = .048) and in general, higher incidence of OHCA during the COVID-19 pandemic compared to prior years [[11] , [12] , [13] ]. However, most of these studies were conducted during the early months of COVID-19 and it is unclear whether these trends continue to persist on a statewide level.

In this study, we aim to characterize the incidence of OHCA during the pandemic period compared to the prior year and describe changes, if any, in OHCA outcomes and survival. This study can help fill the gap regarding long-term impacts of the pandemic beyond the initial first wave on cardiac arrest care and patient outcomes. 

We analyzed adult OHCAs in Texas from the Cardiac Arrest Registry to Enhance Survival (CARES) during March 11-December 31 of 2019 and 2020. The CARES database is a collaboration between Emory University and the Centers for Disease Control and Prevention, which aims to improve cardiac arrest outcomes by using OHCA surveillance data. Data is voluntarily reported by EMS agencies and hospitals from across the country. CARES has standardized quality measurements for benchmarking and quality improvement efforts on the local, state and national level [14, 15] . The national CARES database captures 51% about the U.S. population, approximately 167 million people [14, 15] . The study was approved by the University of Texas Health Science Center at Houston IRB and the CARES Data Sharing Committee (HSC-MS-19-0601).

We stratified cases into different groups of interest: pre-COVID-19 (March 11, 2019 to December 31, 2019) and COVID-19 period (March 11, 2020 to December 31, 2020), representing the period after the emergence and persistence of COVID-19 and a matched period during the prior years. We used March 11, 2020 as the cutoff date as this is when COVID-19 was declared a pandemic by the World Health Organization [16] . We excluded cases witnessed by 9-1-1 responders, arrests occurring at healthcare facilities and pediatric cases (<18 years old). We excluded 2 EMS agencies who did not participate in CARES for the entire study period, representing 0.003% of the original data set.

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Cardiac arrest characteristics were defined as age, gender, race/ethnicity (White, Black, Hispanic, Other), witnessed arrest, initial rhythm type (shockable, non-shockable) and location type (home/residence, public). Our prehospital outcomes of interest were BCPR, public AED use, sustained ROSC, and prehospital termination of resuscitation (TOR). Our hospital survival outcomes of interest were survival to hospital admission, survival to hospital discharge, good neurological outcomes (CPC Score of 1 or 2) and Utstein bystander survival rate (patients surviving to hospital discharge with witnessed bystander arrest, initial shockable rhythm receiving BCPR and/or AED) [17] .

We analyzed the patient arrest characteristics and prehospital care data using descriptive statistics stratified by pre-pandemic and pandemic periods. We calculated the median and interquartile ranges for patient ages. We used Pearson's 2 tests to determine association of variables with the two study years. Similarly, we used Fisher's exact tests for variables with expected frequencies less than 5 to evaluate their association with the two study years. We built mixed multivariable logistic regression models to estimate the adjusted odds ratio (aOR) of outcomes of interest comparing the pre-pandemic and pandemic periods, and stratifying by EMS agency as the random intercept. The models were controlled for the following confounders: age, gender, race/ethnicity, witnessed arrest, initial rhythm type and location type. All statistical analyses were conducted with STATA 16.1.

As shown in Figure 1 , 8,037 patients were included in the analysis. (Figure 1 ). There were 3,619

OHCAs (45.0%) in 2019 compared to 4,418 (55.0%) in 2020 for a total of 8,037 cases (Table 2) .

Across the two study periods, median age, race/ethnicity and witnessed arrest were consistent.

From 2019 to 2020, the proportion of arrests occurring at home or at a residence increased from 80.9% to 86.7% (P < 0.01) ( Table 1) . Additionally, there were slightly more cardiac arrests occurring in the COVID-19 period thought to be related to respiratory causes (8.2% in 2019 vs 8.4% in 2020) while OHCAs secondary to a cardiac etiology decreased (85.1% in 2019 vs 84.6% in 2020) (P = 0.04) ( Table 1) 

Emerging data suggests worsening OHCA outcomes on a national level during the COVD-19

pandemic, but it is not clear if this trend persists on the state level [13] . We hypothesized public interventions, especially those shown to improve OHCA outcomes such as BCPR and PAD would decrease while survival outcomes would worsen. To date, no other state-wide studies have been comparable in terms of geographic size, patient population or temporal length. By utilizing such a comprehensive reach, this study adds to the evidence that OHCA care and outcomes has J o u r n a l P r e -p r o o f continued to worsen in the COVID-19 pandemic period. Better characterization of which aspects of pre-hospital cardiac care have deteriorated due to the pandemic can help drive quality improvement efforts and restore the chain of the survival.

Between the two study periods, the patient demographics (age, gender, race & ethnicity) were similar. However, the total number of cardiac arrests increased from 3,627 in 2019 to 4,443 in 2020, an absolute 22.5% increase. Because the same EMS agencies participated in both study periods, this suggests an absolute increase in cardiac arrests as it cannot be attributed to agency participation. While this general increase is consistent with other studies, estimates of differences in OHCA incidence range from -3% to 191.4% during the early months of the pandemic [18] . In a systematic review by Teoh, et. al, the pooled annual OHCA incidence increased by 39.5% (P < 0.001), which is more in-line with our calculations [19] .

In this study, we used a series of mixed effect logistic regression models, with EMS agency as the random intercept, adjusting for covariates, to calculate adjusted odds ratios and thus the impact of the pandemic on OHCA outcomes of interest. We found that life-saving bystander interventions, BCPR and PAD, worsened relative to the pre-pandemic period and arrests were more likely to occur at home during the COVID-19 period. This is comparable to other estimates which also found decreases in AED usage (OR = 1.78, 95% CI 1.06-2.98) in the pre-COVID-19 period [ [12] , [18] ]. However, study of BCPR has yielded mixed results, with some research suggesting BCPR did not differ significantly during the pandemic period to prior, while others found a decrease (COVID-19: 33.0% versus non-COVID-19: 41.3%, P < 0.001) [ [12] , [13] , [18] ]. A study from Lim, et. al found that OHCAs during the COVID-19 pandemic were more J o u r n a l P r e -p r o o f likely to occur at home (aOR = 1.48, 95% CI 1.24-1.75) and less likely to receive BCPR (aOR = 0.70, 95% CI 0.61-0.81) although 65% of witnessed arrests were by a family member [18] . We would expect for a pandemic spread by a virus with close physical contact, that the frequency of interventions requiring laypersons to be in close proximity to patients (i.e. performing CPR or applying an AED) would decrease due to hesitancy of virus transmission [ [11] , [12] , [20] ].

Because there are less arrests occurring in public settings, the likelihood of a trained layperson able to perform CPR and/or apply an AED would also decrease [ [11] , [21] , [22] ].

In addition to lower rates of BCPR and PAD, we found lower rates of sustained ROSC, increased odds of termination and worsening survival outcomes [ [13] , [22] , [23] , [24] ]. Our estimates of sustained ROSC are consistent with what has been reported in the literature thus far (aOR = 0.61-0.67) [ [13] , [19] , [21] , [22] ]. Our study found the odds of field termination to be slightly lower than that reported in Detroit (OR = 2.36, 95% CI 1.36-4.07) or other studies (OR = 2.46, 95% CI 1.62-3.74) [19, 22] . Across the US, Chan et al found the rate of field termination to be higher in 2020, (53.9% in 2020 versus 39.9% in 2019) increasing not only in areas with high and very high COVID-19 mortality, but even those with the lowest COVID-19 mortality rates [13] .

This increase in field termination is similar to our results.

We found survival to hospital admission and hospital discharge to decrease, while good neurologic outcomes remained unchanged. Our study found rates of survival to hospital admission (OR = 0.56 -0.65) and survival to hospital discharge (OR = 0.46 -0.68) to be slightly higher than what is reported in the literature [ [13] , [19] , [24] , [25] ]. While the rates of good J o u r n a l P r e -p r o o f neurologic scores did not change significantly in our study, conflicting research exists, demonstrating worse or unchanged CPC scores compared to the pre-COVID-19 period [12, 26] .

In Texas, public interventions shown to improve OHCA survival were less frequent during the pandemic and survival outcomes worsened. Odds of field termination increased. Although more arrests occurred at home and non-shockable rhythm was more common, good neurologic outcomes remained unchanged. Future research efforts should identify contributing factors to decreased BCPR and PAD in order to develop targeted education to restrengthen the cardiac chain of survival. Clarifying reasoning behind the increase in field terminations may also shed light on decision making in resource-limited situation or with limited information. This study helps to provide additional explanations as to why OHCA worsened during the pandemic.

Our study had several limitations. Our study was limited to those participants within the Texas CARES catchment, which covers approximately 40.1% of the population. Those participants served by EMS agencies not participating in CARES may have different characteristics leading to a change in study results. The data set does not assess for any variations in quality or processes that may have led to differences in outcomes. For instance, any instance of BCPR is included, but measurements related to compression quality or type of CPR (i.e. compressions only) are not reported. We did not account for individual COVID seropositivity or medical comorbidities, which could affect survival outcomes. Because we conducted our analysis on the aggregate state level, we were unable to account for the microlevel impacts of human geography, which could mask trends on a smaller level.

J o u r n a l P r e -p r o o f

Our study adds state-wide evidence to the national phenomenon of increased OHCA incidence during COVID-19, along with worsening rates of BCPR, PAD use and outcomes. The significance of this study lies in its novelty of geographic size, temporal scope and comprehensive nature of EMS agencies by being part of the CARES database. Our results corroborate prior findings that bystander interventions, field terminations and survival outcomes worsened during the pandemic.

This study was funded by a grant by the Zoll Foundation.

None.

J o u r n a l P r e -p r o o f 

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