Highlights
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Acute cardiovascular hospitalizations in NC declined after the state of emergency order.
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Declines in rates were similar in both urban and rural counties, and older individuals experienced the most substantial declines.
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After reopening measures, there was an abrupt rebound in acute cardiovascular hospitalizations.
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Government orders closely correlate with health care seeking behavior in acute cardiovascular events.
Abstract
Objective
Little is known about the effect of government-issued State of Emergency (SOE) and Reopening orders on health care behaviors. We aimed to determine the effect of SOE and Phase 1 of Reopening orders on hospitalizations for acute myocardial infarction (AMI) or acute decompensated heart failure (ADHF).
Methods
Hospitalizations for AMI and ADHF in the UNC Health system, which includes 10 hospitals in both urban and rural counties, were identified. An interrupted time series design was used to compare weekly hospitalization rates for eight weeks before the March 10 th SOE declaration, eight weeks between the SOE order and Phase 1 of Reopening order, and the subsequent eight weeks.
Results
Overall, 3,792 hospitalizations for AMI and 7,223 for ADHF were identified. Rates before March 10 th were stable. AMI/ADHF hospitalizations declined about 6% per week in both urban and rural hospitals from March 11 th to May 5 th . Larger declines in hospitalizations were seen in adults ≥65 years old (-8% per week), women (-7% per week), and White individuals (-6% per week). After the Reopening order, AMI/ADHF hospitalizations increased by 8% per week in urban centers and 9% per week in rural centers, including a significant increase in each demographic group. The decline and rebound in acute CV hospitalizations were most pronounced in the two weeks following the government orders.
Conclusions
AMI and ADHF hospitalization rates closely correlated to SOE and Reopening orders. These data highlight the impact of public health measures on individuals seeking care for essential services; future policies may benefit from clarity regarding when individuals should present for care.
Graphical abstract
1
Introduction
An unexpected decline in rates of hospitalizations for a broad range of cardiovascular conditions has been observed worldwide during the coronavirus disease-2019 (COVID-19) pandemic . The etiology for this remains unclear with proposed etiologies including patient fears of developing COVID-19 in the hospital setting, decreased air pollution, increased sleep duration, and less work-related stress. Government issued stay at home orders have been shown to affect elective procedures [ , ], but it is unclear if these mandates affected patients seeking emergency care.
The first person to test positive for coronavirus in North Carolina (NC) was in Raleigh on March 3, 2020. On March 9, there were 6 confirmed cases of COVID-19 in Wake County and 7 in the state. The next day, the Governor issued a State of Emergency (SOE) order to coordinate responses to COVID . On March 14, K-12 schools were closed and on March 17, 2020, restaurants and bars were closed. All elective and non-urgent surgeries and procedures were suspended by order of the Department of Health and Human Services as of March 23. On March 27, the Governor ordered NC residents to stay at home for 30 days. On that day, there were 232 confirmed cases of COVID-19 in NC. On May 5, the Governor announced that NC would enter Phase 1 of Reopening on May 8 which would permit the reopening of ‘nonessential’ businesses (e.g. clothing and hardware stores), worship centers, parks and childcare facilities and allow people to leave their homes for commercial purposes.
While much remains unknown about COVID-19, older adults and certain racial/ethnic populations disproportionately account for more severe COVID-19 illnesses and deaths . It is also apparent that the disease has disproportionately impacted urban areas [ , ]. Therefore, there may be variation in perception of exposure risk to Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-COV-2) which may have a differential effect on the trends in hospitalizations in urban versus rural hospitals and across demographic groups. The University of North Carolina (UNC) Health system spans the state of NC and includes 11 hospitals equitably distributed throughout urban and rural areas; it serves the diverse population of NC, which is 28% rural and 22% Black . Each of these hospitals is well equipped to provide care for patients who may need acute CV care such as acute myocardial infarction (AMI) or acute decompensated heart failure (ADHF). The unique geography of the state of NC and the distribution of UNC hospitals throughout the state provided an opportunity to examine the effect of government issued orders in NC.
2
Methods
Hospitalizations containing a hospital billed discharge diagnosis of acute CV conditions of interest with a primary discharge date between January 15 th , 2020 and June 30 th , 2020 at inpatient care entities across the UNC Health system were retrospectively examined. Hospitalizations were categorized according to International Classification of Diseases, Tenth Revision (ICD-10) coding into the following categories: AMI, ADHF, and cardiac arrest using the Informatics for Integrating Biology and the Bedside Platform (i2b2) (Supplemental Table 1). UNC Health system began recording COVID-19 data in its centers on March 12 th (Central illustration and supplemental figure 1). i2b2 is the flagship tool developed by the i2b2 Center, in the North Carolina Translational & Clinical Sciences Institute (NC TraCS) . i2b2 provides a way for researchers to query the Carolina Data Warehouse for Health, a central data repository containing clinical, research, and administrative data sourced from the UNC Health System. Researchers can apply criteria for patient demographics, encounter information, ICD-9-CM and ICD-10-CM diagnoses, ICD-9-CM/ICD-10-CM/CPT/HCPCS procedure codes, vitals, laboratory results, discharge disposition, and medications. To protect patient information, i2b2 does not report frequencies <10; we used 9 as an estimate when values were suppressed. The i2b2 at the University of North Carolina is supported by the National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, through Grant Award Number UL1TR002489.
There are 100 counties in NC of which 80 counties were identified as rural, 14 as suburban, and 6 as urban based on the population densities derived from 2014 estimates of the 2010 U.S Census population by the NC Rural Center . Data were available for 10 of 11 UNC health system hospitals (Onslow Memorial Hospital was acquired in 2019 and was not reporting to i2b2 at the date of data collection); these hospitals were categorized into urban, suburban, or rural based on the county in which they were located ( Fig. 1 ). For this study, we collapsed the urban and suburban counties into one analytic category and compared with rural counties. Urban/suburban hospitals included UNC Medical Center, UNC REX Hospital, and Pardee Hospital. Rural hospitals included Caldwell Hospital, Chatham Hospital, Johnston Hospital, Lenoir Memorial Hospital, Nash Hospital, UNC Rockingham Hospital, and Wayne Memorial Hospital ( Fig. 1 ). This study was considered exempt from institutional review board approval as i2b2 contains only deidentified information.
Demographics and clinical characteristics including age, sex, race, diabetes mellitus, and hypertension, chronic obstructive pulmonary disease, discharge disposition, and length of stay data were collected. To account for the large daily variation in hospital volume during the pandemic, weekly rates of acute CV diagnoses of interest were calculated. Age was categorized as ≥65 years and <65 years old. To examine the impact of COVID-19 on trends in CV hospitalizations, we utilized an interrupted time series (ITS) design and segmented log-linear negative binomial regression. The ITS design is a quasi-experimental approach and considered one of the strongest methods for evaluating longitudinal effects of interventions [ , ]. Briefly, the study period is divided into pre-intervention and post-intervention segments, and separate regression analyses are built for each period. Using ITS, we then compared both the immediate impact (intercepts) and weekly trends (slopes) from the eight weeks before March 10 th , 2020 (January 15 th –March 10 th ) to the eight weeks after (March 11 th –May 5 th ), and then the eight weeks after March 10 th to the following eight weeks (May 6 th –June 30 th ) during reopening. In-hospital mortality and cardiac arrest were also examined using similar methods. Categorical variables were compared using Chi-square tests and continuous variables were compared using Kruskal Wallis test, as appropriate. All analyses were done using SAS version 9.4 (SAS Inc, Cary, NC) and R version 4.0.0 (2020, R Core Team, Vienna, Austria).
3
Results
A total of 11,015 hospitalizations for AMI or ADHF were identified from January 15, 2020 to June 30, 2020 in the UNC Health system, including 3792 for AMI (34%) and 7223 for ADHF (66%). A breakdown showed that 6895 (63%) occurred at hospitals in urban counties, 5943 (54%) were men, 7099 (64%) were White, 3372 (31%) were Black, and 7064 (64%) were 65 years or older.
There were 1462 AMI and 2776 ADHF admissions in the eight weeks preceding the SOE declaration in NC (January 15 th to March 10 th ), compared to 1089 AMI and 2088 ADHF admissions from March 11 th to May 5 th , and 1241 AMI and 2359 ADHF admissions from May 6 th to June 30 th ( Table 1 , Fig. 2 ). Incident rate ratios (IRR) representing average weekly AMI/ADHF hospitalizations during the three time intervals in our study are displayed in Table 2 , stratified by hospital location and demographic group. Between January 15 th and March 10 th , there were an average of 512 (95% CI 457, 574) AMI or ADHF hospitalizations per week at centers in the UNC Health system, and trends were stable (IRR 1.01 95% CI 0.99, 1.03, p = 0.52). Following the March 10 th SOE declaration, there was a 33.8% drop in AMI/AHDF hospitalizations from March 11 th through March 24 th which then stabilized. Overall admissions for AMI or ADHF declined by about 6% per week in the 8 weeks after the SOE order (change in intercept p = 0.32, change in slope p = 0.0002). In the first three weeks during Phase 1 of Reopening, there was a substantial increase in rates of hospitalization for AMI or ADHF which then stabilized; overall rates increased by 8% per week during the 8 weeks after reopening (change in intercept p = 0.0009, change in slope p < 0.0001, Central Illustration, panel A).
| January 15, 2020–March 10, 2020 | March 11, 2020–May 5, 2020 | P(2-sided) a | May 6, 2020–June 30, 2020 | P(2-sided) b | |
|---|---|---|---|---|---|
| AMI/ADHF hospitalizations, n | 4238 | 3177 | – | 3600 | – |
| Urban Center, n (%) | 2669 (63) | 1982 (62) | 0.60 | 2244 (62) | 0.96 |
| Rural Center, n (%) | 1569 (37) | 1195 (38) | 1356 (38) | ||
| Age ≥ 65 years, n (%) | 2855 (67) | 1967 (62) | <0.0001 | 2242 (62) | 0.77 |
| Men, n (%) | 2328 (55) | 1671 (53) | 0.05 | 1944 (54) | 0.25 |
| Race, n (%) | |||||
| White | 2830 (67) | 1976 (62) | 0.0004 | 2293 (64) | 0.20 |
| Black | 1223 (29) | 1008 (32) | 0.007 | 1141 (32) | 0.98 |
| Other | 185 (4) | 193 (6) | 0.0009 | 166 (5) | 0.007 |
| Diabetes Mellitus c | 1416 (33) | 1001 (32) | 0.08 | 1095 (30) | 0.33 |
| Hypertension d | 2354 (56) | 1686 (53) | 0.03 | 1861 (52) | 0.26 |
| Chronic Obstructive Pulmonary Disease e | 1106 (26) | 783 (25) | 0.16 | 805 (22) | 0.03 |
| Length of Stay > 2 days | 1790 (42) | 1325 (42) | 0.65 | 1451 (40) | 0.24 |
| Discharge to Skilled Nursing Facility | 786 (19) | 470 (15) | <0.0001 | 514 (14) | 0.55 |
| In-hospital Mortality, n (%) | 290 (7) | 218 (7) | 0.97 | 187 (5) | 0.004 |
| Cardiac Arrest | 207 (32) | 216 (34) | – | 216 (34) | – |
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