REVISTA DE INVESTIGACIÓN CLÍNICA Contents available at PubMed www.clinicalandtranslationalinvestigation.com Rev Invest Clin. 2022;74(3):135-46 ORIGINAL ARTICLE Safety and Revisit Related to Discharge the Sixty-one Spanish Emergency Department Medical Centers Without Hospitalization in Patients with COVID-19 Pneumonia. A Prospective Cohort Study UMC-Pneumonia COVID-19 Javier Jacob1*, Arantxa Albert-Casado1, Juan G. Del-Castillo2, Pere Llorens-Soriano3, Sonia Jiménez-Hernández4, Guillermo Burillo-Putze5, Alfonso Martín-Martínez6, Francisco J. Martín-Sánchez2, Eric J. García-Lamberechts2, Pascual Piñera-Salmerón7, Aitor Alquézar-Arbé8, Carles Ferre-Losa1, María Á. Juan-Gómez9, Leticia Serrano-Lázaro10, José Noceda-Bermejo11, Manuel Salido-Mota12, María J. Fortuny-Bayarri13, Matilde González-Tejera14, José M. Ferreras-Amez15, Elena Díaz-Fernández16, Eva Quero-Motto17, Ana Peiró-Gómez18, Enrique Martín-Mojarro19, Ferran Llopis-Roca1, Arturo Huerta-García20, Jorge Pedraza-García21, Napoleón Meléndez-Cálix22, José V. Brazó-Aznar23, María J. Cano-Cano24, and Óscar Miró25 Emergency Department, 1Hospital Universitari de Bellvitge, L’Hospitalet de Llobregat, Barcelona; 2Hospital Clínico San Carlos, IDISSC, Universidad Complutense, Madrid; 3Hospital General de Alicante, University Miguel Hernández, Elche, Alicante; 4Hospital Clínic, IDIBAPS, University of Barcelona, Barcelona; 5Hospital Universitario de Canarias, Tenerife; 6Hospital Universitario de Móstoles, Madrid; 7Hospital Reina Sofía, Murcia; 8Hospital de la Santa Creu i Sant Pau, Barcelona; 9Hospital Universitario Doctor Peset, Valencia; 10Hospital Universitario y Politécnico La Fe, Valencia; 11Hospital Clínico Universitario de Valencia, Valencia; 12Hospital Universitario Regional de Málaga, Málaga; 13Hospital Francesc de Borja de Gandia, Valencia; 14Hospital General Universitario de Elche, Alicante; 15Hospital Clinico Universitario Lozano Blesa, Zaragoza; 16Hospital Universitario Sant Joan, Alicante; 17Hospital Universitario Virgen de la Arrixaca, Murcia; 18Hospital de Llíria, Valencia; 19Hospital de Sant Pau i Santa Tecla, Tarragona; 20Clinica Sagrada Familia, Barcelona; 21Hospital Valle de los Pedroche de Pozoblanco, Córdoba; 22Hospital Virgen de los Lírios, Alcoy, Alicante; 23Hospital Universitario de la Ribera, Valencia; 24Hospital Arnau de Vilanova, Valencia; 25Hospital Clínic de Barcelona, Spain ABSTRACT Background: Information is needed on the safety and efficacy of direct discharge from the emergency department (ED) of patients with COVID-19 pneumonia. Objectives: The objectives of the study were to study the variables associated with dis- charge from the ED in patients presenting with COVID-19 pneumonia, and study ED revisits related to COVID-19 at 30 days (EDR30d). Methods: Multicenter study of the SIESTA cohort including 1198 randomly selected COVID patients in 61 EDs of Spanish medical centers from March 1, 2020, to April 30, 2020. We collected baseline and related characteristics of the acute *Corresponding author: Received for publication: 24-01-2022 Javier Jacob Approved for publication: 08-02-2022 E-mail: jjacob@bellvitgehospital.cat DOI: 10.24875/RIC.22000021 0034-8376 / © 2022 Revista de Investigación Clínica. Published by Permanyer. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 135 REV INVEST CLIN. 2022;74(3):135-46 episode and calculated the adjusted odds ratios (aOR) for ED discharge. In addition, we analyzed the variables related to EDR30d in discharged patients. Results: We analyzed 859 patients presenting with COVID-19 pneumonia, 84 (9.8%) of whom were discharged from the ED. The variables independently associated with discharge were being a woman (aOR 1.890; 95%CI 1.176- 3.037), age < 60 years (aOR 2.324; 95%CI 1.353-3.990), and lymphocyte count > 1200/mm3 (aOR 4.667; 95%CI 1.045- 20.839). The EDR30d of the ED discharged group was 40.0%, being lower in women (aOR 0.368; 95%CI 0.142-0.953). A total of 130 hospitalized patients died (16.8%) as did two in the group discharged from the ED (2.4%) (OR 0.121; 95%CI 0.029- 0.498). Conclusion: Discharge from the ED in patients with COVID-19 pneumonia was infrequent and was associated with few variables of the episode. The EDR30d was high, albeit with a low mortality. (REV INVEST CLIN. 2022;74(3):135-46) Keywords: Pneumonia COVID-19. Emergency department. Revisit. Discharge. INTRODUCTION visits were poorly studied13,14. Therefore, our objec- tive was to study the variables associated with direct The COVID-19 pandemic is one of the most impor- discharge of patients with COVID-19 from the ED and tant challenges for emergency medicine in this cen- the safety of this decision in terms of mortality and tury. The initial lack of knowledge of this disease and ED revisits. its expression as a pandemic has led to the need for structural and management resources which were previously unknown in the emergency department METHODS (ED)1-6. A health alarm was generated by this new infection due to the elevated number of patients Data from the UMC-19 project (Unusual Manifesta- presenting pneumonia with acute respiratory dis- tions of COVID-19) were analyzed to conduct the tress syndrome (ARDS) requiring admission to inten- present study. The UMC-19 project is a multicenter, sive care units (ICUs) with invasive or non-invasive observational study within a prospectively studied ventilatory support and carrying an elevated mortal- cohort carried out by the Spanish Investigators in ity. This context has made the presence of pneumo- Emergency Situations TeAm (SIESTA) research net- nia by COVID-19 an area of uncertainty in the eval- work15. This project has created a randomly selected uation of risk in the ED and, consequently, has led to control group of patients with COVID-19 recruited a high percentage of hospital admissions and never- from 61 Spanish EDs participating in the project, before practiced situations in the ED7,8. Therefore, which included from 10 to 30 patients each according critical decisions in the ED must be made to ensure to the reference population of the ED. The SIESTA that patients with pneumonia can be safely dis- cohort includes 1198 patients. The patient inclusion charged to avoid hospital overcrowding and collapse period was from March 1, 2020, to April 30, 2020. of the system. These decisions must be supported COVID-19 cases were defined as patients with a pos- by scientific evidence to safeguard against inade- itive result in the reverse transcription-polymerase quate discharges that result in bad clinical results. chain reaction test obtained from a nasopharyngeal The data of large series collected in studies of pa- swab at admission to the ED or from a second confir- tients with COVID-19 have reported some variables mation sample during hospitalization in the case of related to bad prognoses such as age, the presence clinical suspicion. of chronic comorbidities, an elevation of inflamma- tory parameters and D-dimer, and the presence of A total of 43 variables were collected: two demo- acute respiratory failure or lymphopenia, among oth- graphic (age and gender); 11 comorbidities (hyper- ers9-11. There are currently models for predicting tension, dyslipidemia, diabetes mellitus, chronic ob- severe manifestations and mortality from COV- structive pulmonary disease, coronary artery disease, ID-1912. However, at the time of the first wave of clinically estimated obesity, cerebrovascular disease, the pandemic, there was little clinical experience chronic kidney disease, chronic heart failure, demen- related to COVID-19 pneumonia that would allow tia, and active cancer); 16 symptoms and signs at ED emergency physicians to safely discharge patients arrival (lasting symptoms, fever, rhinorrhea, cough, without requiring hospital admission, and ED return expectoration, dyspnea, vomiting, diarrhea, anosmia, 136 J. Rodríguez et al.: UMC-PNEUMONIA COVID-19 DISCHARGE SAFETY dysgeusia, temperature, systolic blood pressure, heart in 2 × 2 tables when the expected values were <5), rate, respiratory rate, oxygen saturation by pulse ox- and Student’s t-test for independent measures was imetry, and fraction of inspired oxygen); 10 labora- used for the quantitative variables, if the distribution tory findings (C-reactive protein, creatinine, aspartate did not affect the principle of normality (analyzed amino transferase, alanine amino transferase, ferritin, using Kolmogorov–Smirnov test) or using the non- lactate dehydrogenase, leukocytes, lymphocytes, parametric Mann–Whitney U-test if affected. The platelets, and D-dimer); and four chest X-rays data magnitude of association was expressed as a crude (interstitial infiltrates, opacities, pleural effusion, and odds ratio (OR) with a 95% confidence interval (CI). cardiomegaly). For the study, only data of patients A first analysis was performed to investigate the vari- presenting with pneumonia in the chest X-rays de- ables related to discharge directly from the ED. To fined by the presence of opacity or interstitial infil- investigate independent associations, adjusted ORs trates were analyzed. In all cases, the review and de- (aOR) were calculated; for this, variables that were scription of the chest X-rays were carried out by the statistically significant in the univariate analysis were emergency physician responsible for the patient. The introduced in the multivariate analysis. Taking into scores of the quick Sequential Organ Failure Assess- account, the large number of variables analyzed in the ment (qSOFA) and CRB-65 scales were calculated us- study and that many would foreseeably present sta- ing the data collected. The patients were divided into tistically significant differences, the investigative two groups based on whether hospital admission or team decided to perform multivariate analysis in two discharge directly from the ED was required, and as- blocks (baseline related and acute episode related) to sociations between the two groups were studied. Af- make a stable logistic regression model. We then per- terward, we studied the variables associated with formed a second analysis of the variables associated revisit to the ED related to COVID-19 within 30 days with EDR30d in the group discharged from the ED. For after discharge (EDR30d). The principal investigators all analyses, differences were considered statistically (PIs) of each participating center reviewed the clinical significant when the p value was less than 0.05 or histories of the EDs and hospitalization wards to ob- when the 95%CI of the OR excluded the value 1. The tain the study data. The final diagnosis of COVID-19 IBM SPSS Statistics V26 statistical program was used and the adverse events was collected locally by the PI for the statistical analyses. of each center. Follow-up at 30 days was made by review of the electronic clinical histories of the pa- tients. RESULTS The study was approved by the Ethics Committee in Of the 1168 patients recruited in the SIESTA cohort, Clinical Research of the Hospital Clínic de Barcelona, at the time of analysis of the data, chest X-rays had Institut d'Investigacions Biomèdiques August Pi i Su- not been performed in 25 cases (Fig. 1). Of the re- nyer (IDIBAPS) (protocol HCB/2020/0534). In view maining 1143 patients, 859 (75.2%) presented with of the urgent need of data collection, waiver of writ- pneumonia and were included in the final study co- ten informed consent was granted by the ethics com- hort. Of these, 84 patients (9.8%) were discharged mittee. Patient information included in the database directly from the ED. Table 1 shows the characteris- was encoded to ensure anonymity and patient confi- tics of the whole cohort and the variables associated dentiality. with discharge from the ED. When comparing the basal characteristics of these patients with those requiring hospital admission, those discharged from Statistical analysis the ED were younger, there was a greater proportion of women, and they presented fewer comorbidities. Categorical variables are expressed as absolute and In relation to the characteristics of the acute epi- relative frequencies, and continuous data are present- sode, there was a lower presence of dyspnea, a high- ed as means with standard deviation (SD) or, if not er presence of respiratory rate < 24 bpm, and O2 normally distributed, as median, and interquartile saturation > 92%. In regard to the analytical data of range. For comparisons, the Chi-square test was used the group discharged from the ED, a greater propor- for the qualitative variables (or the Fisher’s exact test tion of patients presented C-reactive protein values 137 REV INVEST CLIN. 2022;74(3):135-46 Figure 1. Patient inclusion flowchart. of < 10 mg/L, creatinine < 1.2 mg/dL, ferritin < 300 CI 1.045-20.839). A score ≥ 1 point in the qSOFA ng/mL, lactate dehydrogenase < 240 IU/L, lympho- and CRB-65 scales was related to greater hospital cyte count > 1200 per mm3, and D-dimer < 1000 admission. ng/mL. Chest X-rays showed a greater proportion of unilateral opacities. Figure 2 shows the estimation of Among the whole cohort, 132 patients died (15.4%), the adjusted effect (ordered by the aOR value) of the 130 from the hospitalized group (16.8%), and two in different baseline and acute episode characteristics the group discharged from the ED (2.4%), with a of the patients included in the multivariate model of crude OR of 0.121 (95%CI 0.029-0.498). In the latter the probability of hospital admission or discharge group, a total of 30 patients (40.0%) revisited the ED, from the ED in patients with COVID-19 pneumonia. but only 6 (8.0%) required hospitalization. Table 2 Discharge from the ED was associated with being a shows the comparative analysis based on EDR30d. woman (aOR of 1.890; 95% CI 1.176-3.037), age < The only variable significantly associated with a low- 60 years (aOR of 2.324; 95% CI 1.353-3.990), and er EDR30d was being a woman, with an OR of 0.368 lymphocyte count > 1200/mm3 (aOR of 4.667; 95% (95%CI 0.142-0.953). 138 J. Rodríguez et al.: UMC-PNEUMONIA COVID-19 DISCHARGE SAFETY Table 1. Characteristics of the study patients, according to hospital admission or ED discharge. Odds ratio calculated for ED discharge Total COVID-19 Hospital ED discharge p-value OR pneumonia admission (n = 84) (95%CI) (n = 859) (n = 775) Demographics Age (years) 64.4 65.5 54.8 <0.001 1.039 (mean [SD]) (16.7) (16.5) (15.4) (1.025-1.054) Age < 60 years 332 277 55 <0.001 3.410 (38.6) (35.7) (65.5) (2.124-5.473) Female gender 353 306 47 0.004 1.947 (41.1) (39.5) (56.0) (1.236-3.066) Comorbidities (n [%]) Hypertension 398 377 21 <0.001 0.352 (46.3) (48.6) (25.0) (0.211-0.588) Dyslipidemia 312 290 22 0.042 0.593 (36.3) (37.4) (26.2) (0.357-0.986) Diabetes mellitus 173 165 8 0.011 0.389 (20.1) (21.3) (9.5) (0.184-0.823) Chronic obstructive 86 84 2 0.014 0.201 pulmonary disease (10.0) (10.8) (2.4) (0.048-0.831) Coronary artery disease 70 68 2 0.042 0.254 (8.1) (8.8) (2.4) (0.061-0.999) Obesity 127 121 6 0.038 0.416 (clinically estimated) (14.8) (15.6) (7.1) (0.177-0.975) Cerebrovascular disease 54 51 3 0.280 (6.3) (6.6) (3.6) Chronic kidney disease 65 64 1 0.020 0.134 (7.6) (8.3) (1.2) (0.018-0.977) Chronic heart failure 68 68 0 0.005 0.894 (7.9) (8.8) (0.0) (0.873-0.916) Dementia 69 64 5 0.460 (8.0) (8.3) (6.0) Active cancer 86 84 2 0.014 0.201 (10.0) (10.8) (2.4) (0.048-0.831) Symptoms at ED arrival [n (%)] Symptom onset (days) 7.8 7.7 8.5 0.302 (mean [SD]) (5.6) (5.5) (6.5) Fever 592 541 51 0.087 (68.9) (69.8) (60.7) Rhinorrhea 90 81 9 0.940 (10.5) (10.5) (10.7) Cough 511 456 55 0.239 (59.5) (58.8) (65.5) Expectoration 139 127 12 0.619 (16.2) (16.4) (14.3) Dyspnea 506 466 40 0.027 0.603 (58.9) (60.1) (47.6) (0.384-0.947) Vomiting or diarrhea 220 196 24 0.513 (25.6) (25.3) (28.6) (Continues) 139 REV INVEST CLIN. 2022;74(3):135-46 Table 1. Characteristics of the study patients, according to hospital admission or ED discharge. Odds ratio calculated for ED discharge (continued) Total COVID-19 Hospital ED discharge p-value OR pneumonia admission (n = 84) (95%CI) (n = 859) (n = 775) Symptoms at ED arrival [n (%)] Anosmia 59 51 8 0.311 (6.9) (6.6) (9.5) Dysgeusia 62 52 10 0.081 (7.2) (6.7) (11.9) Signs at ED arrival (n [%]) Temperature (°C) 36.9 36.9 36.7 0.059 (mean [SD]) (0.9) (1.0) (0.9) SBP (mmHg) 128.8 128.8 129.5 0.701 (mean [SD]) (21.2) (21.7) (16.7) Heart rate (bpm) 89.5 89.2 92.0 0.159 (mean [SD]) (17.1) (16.9) (19.7) Respiratory rate 621 546 75 <0.001 4.160 < 24 bpm (73.9) (72.0) (91.5) (1.887-9.173) Basal saturation O2 677 600 77 0.002 3.208 > 92% (78.8) (77.4) (91.7) (1.453-7.082) Laboratory findings (n [%]) C-reactive protein 549 490 59 0.005 2.438 < 10 mg/L (68.3) (66.8) (83.1) (1.286-4.622) Creatinine 756 681 75 0.003 1.110 < 1.2 mg/dL (90.3) (89.4) (100) (1.084-1.137) AST < 40 IU/L 395 359 36 0.431 (64.2) (63.8) (69.2) ALT < 40 IU/L 516 468 48 0.501 (71.4) (71.0) (75.0) Ferritin < 300 ng/mL 104 93 11 0.026 2.553 (27.7) (26.4) (47.8) (1.089-5.983) LDH < 250 IU/L 238 206 32 0.003 2.218 (34.9) (33.2) (52.5) (1.306-3.766) Leukocyte count 114 108 6 0.145 > 4000 per mm3 (13.5) (14.0) (8.0) Lymphocyte count 301 252 49 <0.001 4.402 > 1200 per mm3 (36.7) (33.6) (69.0) (2.603-7.443) Platelets 654 590 64 0.095 > 150,000 per mm3 (77.7) (76.9) (85.3) D-dimer < 1000 ng/mL 479 422 57 0.006 2.409 (67.9) (66.4) (82.6) (1.265-4.586) Chest X-rays findings (n [%]) Interstitial lung infiltrates 486 445 41 0.130 (56.6) (57.4) (48.8) Ground-glass lung 696 630 66 0.546 opacities (81.0) (81.3) (78.6) Central 93 86 7 0.448 (13.7) (14.0) (10.6) (Continues) 140 J. Rodríguez et al.: UMC-PNEUMONIA COVID-19 DISCHARGE SAFETY Table 1. Characteristics of the study patients, according to hospital admission or ED discharge. Odds ratio calculated for ED discharge (continued) Total COVID-19 Hospital ED discharge p-value OR pneumonia admission (n = 84) (95%CI) (n = 859) (n = 775) Chest X-rays findings (n [%]) Unilateral 236 197 39 <0.001 3.175 (33.9) (31.3) (59.1) (1.890-5.334) Pleural effusion 34 33 1 0.241 (4.2) (4.5) (1.2) Cardiomegaly 64 60 4 0.301 (7.9) (8.2) (4.9) Risk score (n [%]) qSOFA≥ 1 points 309 296 13 <0.001 0.294 (36.8) (39.1) (15.9) (0.160-0.541) CRB65 ≥ 1 points 465 440 25 <0.001 0.317 (55.4) (58.0) (30.5) (0.194-0.518) DISCUSSION criteria of severe pneumonia. Indeed, being a woman, being young, and the absence of lymphopenia were In our series, a significant proportion of patients with the only variables significantly associated with ED COVID-19 attending the ED presented with pneumo- discharge. There are multiple tools for the evaluation nia and required hospital admission. Those dis- of risk for bacterial pneumonia, including the Pneu- charged from the ED were more often women under monia Severity Index, CURB-65, and CRB-6517-19. the age of 60 with mild or no lymphopenia. However, These scales are very commonly used since they the EDR30d was high but few patients needed hos- assess the risk of mortality of the episode and help pitalization and mortality was low, and therefore, in decision-making. However, differences between these discharges may be considered as safe. The community-acquired pneumonia and COVID-19 COVID-19 pandemic is one of the greatest challeng- pneumonia have been observed and may imply a dif- es that EDs have faced to date. In a situation in which ferent evolution of the disease. Based on indirect the health-care system has bordered on the collapse, data, if it is taken into account that the mortality in and health-care personnel have been exposed to a our series was 15.4%, it can be said that mortality high risk of contagion and an unprecedented work- by COVID-19 pneumonia could be up to 50% higher load, emergency medicine physicians have been up than that of community-acquired pneumonia20,21. At against an unforeseeable situation. All of these cir- present, different predictive models have been pro- cumstances have occurred within the context of a posed for COVID-19 infection. However, many of new, previously unknown infectious disease linked these scales have limitations: highly variable clinical with an elevated need for hospital admission due to scoring performance, undetermined or high risk of the presentation of severe, heterogeneous complica- bias, retrospective design, or performed early in the tions such as multiorgan dysfunction, ARDS, septic pandemic12. shock, disseminated intravascular coagulation, and thromboembolic events requiring ICU admission and The variables that emergency physicians have consid- with a high mortality8-12,16. For all these reasons, it ered to be well related to safe decision-making have is logical that our results reflect the high number of been few, but based on clinical judgment. Age is a hospital admissions in patients with COVID-19 with variable widely related to worse outcomes in patients pneumonia, even in patients who did not present with SARS-CoV-2 infection. With an increase in age, 141 REV INVEST CLIN. 2022;74(3):135-46 Figure 2. Estimation of the adjusted effect of the different baseline patient characteristics included in the multivariate model on the probability of admission or discharge from the ED in patients with COVID-19 pneumonia *The OR value provided by the adjusted logistic regression model was extremely low (0.000) and the confidence interval of 95% could not be calculated. CI: confidence interval. LDH: lactate dehydrogenase. the proportion of patients who evolve to more severe optimal cut point in this decision together with the forms of infection and require ICU admission increas- remaining clinical, analytical, and radiological crite- es. A recent meta-analysis with 611,583 subjects ria22. Males present more severe COVID-19 infection, shows that all age groups had significantly higher with a greater need for hospital admission, admission mortality compared to the immediately younger age to an ICU, and intubation23. The reason why men group. The greatest increase in the risk of mortality present more severe clinical forms is not clear, and in was seen in patients aged 60-69 years compared with fact, this circumstance was also observed in infection those aged 50-59. Advanced age is, therefore, one of by MERS-CoV and SARS-CoV24. It is likely that the the variables most clearly related to the need for clinical presentation in men is more severe and more hospitalization, and probably, the age of 60 is the often leads to the decision for hospital admission. The 142 J. Rodríguez et al.: UMC-PNEUMONIA COVID-19 DISCHARGE SAFETY Table 2. Characteristics of patients with pneumonia COVID-19 depending on revisit to the emergency department at 30 days (EDR30d) related to COVID-19 Total COVID-19 COVID-19 pneumonia COVID-19 pneumonia p-value pneumonia with EDR30d without EDR30d (n = 75) (n = 30) (n = 45) Demographics Age (years) 54.8 (15.4) 54.7 (13.7) 54.1 (15.6) 0.862 (mean [SD]) Age < 60 years 51 (68.0) 22 (73.3) 29 (64.4) 0.419 Female gender 41 (54.7) 12 (40.0) 29 (64.4) 0.037 Other comorbidities Hypertension 18 (24.0) 7 (23.3) 11 (24.4) 0.912 Dyslipidemia 20 (26.7) 6 (20.0) 14 (31.1) 0.286 Diabetes mellitus 8 (10.7) 4 (13.3) 4 (8.9) 0.706 Chronic obstructive pulmonary 2 (2.7) 1 (3.3) 1 (2.2) 1.000 disease Coronary artery disease 2 (2.7) 1 (3.3) 1 (2.2) 1.000 Obesity (clinically estimated) 6 (8.0) 2 (6.7) 4 (8.9) 1.000 Cerebrovascular disease 2 (2.7) 1 (3.3) 1 (2.2) 1.000 Chronic kidney disease 1 (1.3) 1 (3.3) 0 (0.0) 0.400 Chronic heart failure 0 (0.0) - - - Dementia 4 (5.3) 1 (3.3) 3 (6.7) 0.646 Active cancer 2 (2.7) 2 (6.7) 0 (0.0) 0.157 Symptoms at ED arrival Symptom duration (days) 8.5 9.1 (7,3) 7.6 (5.7) 0.327 (mean [SD]) (6.5) Fever 45 (60.0) 18 (60.0) 27 (60.0) 1.000 Rhinorrhea 9 (12.0) 4 (13.3) 5 (11.1) 1.000 Cough 49 (65.3) 22 (73.3) 27 (60.0) 0.235 Expectoration 12 (16.0) 5 (16.7) 7 (15.6) 1.000 Dyspnea 37 (49.3) 15 (50.0) 22 (48.9) 0.925 Vomiting or diarrhea 22 (29.3) 10 (33.3) 12 (26.7) 0.534 Anosmia 8 (10.7) 2 (6.7) 6 (13.3) 0.464 Dysgeusia 9 (12.0) 2 (6.7) 7 (15.6) 0.301 Signs at ED arrival Temperature (°C) 36.7 (0.9) 36.6 (0.9) 36.7 (1.0) 0.680 (mean [SD]) SBP (mmHg) 129.5 (16.7) 129.5 (17.5) 129.1 (16.6) 0.917 (mean [SD]) (Continues) 143 REV INVEST CLIN. 2022;74(3):135-46 Table 2. Characteristics of patients with pneumonia COVID-19 depending on revisit to the emergency department at 30 days (EDR30d) related to COVID-19 (continued) Total COVID-19 COVID-19 pneumonia COVID-19 pneumonia p-value pneumonia with EDR30d without EDR30d (n = 75) (n = 30) (n = 45) Signs at ED arrival Heart rate (bpm) 92.0 (19.7) 90.1 (16.5) 94.8 (21.7) 0.319 (mean [SD]) Respiratory rate 66 (90.4) 28 (93.3) 38 (88.4) 0.692 < 24 bpm Basal saturation 66 (88.0) 27 (90.0) 39 (86.7) 0.733 O2 > 92% Laboratory findings [mean (SD)] C-reactive protein 52 (81.3) 23 (85.2) 29 (78.4) 0.491 < 10 mg/L Creatinine < 1.2 mg/dL 65 (95.6) 25 (92.6) 40 (97.6) 0.558 AST< 40 IU/L 30 (66.7) 13 (72.2) 17 (63.0) 0.519 ALT< 40 IU/L 43 (75.4) 16 (66.7) 27 (81.8) 0.189 Ferritin < 300 ng/mL 11 (47.8) 4 (36.4) 7 (58.3) 0.292 LDH < 250 IU/L 27 (49.1) 12 (44.4) 15 (53.6) 0.498 Leukocyte count 65 (94.2) 26 (92.9) 39 (95.1) 1.000 > 4000 per mm3 Lymphocyte count 45 (68.2) 19 (67.9) 26 (68.4) 0.961 > 1200 per mm3 Platelets > 150,000 59 (86.8) 24 (85.7) 35 (87.5) 1.000 per mm3 D-dimer < 1000 ng/mL 52 (82.5) 19 (76.0) 33 (86.8) 0.320 Chest X-rays Interstitial lung infiltrates 38 (50.7) 19 (63.3) 19 (42.2) 0.073 Ground-glass lung opacities 57 (76.0) 23 (76.7) 34 (75.6) 0.912 Central 5 (8.8) 2 (8.7) 3 (8.8) 1.000 Unilateral 32 (56.1) 11 (47.8) 21 (61.8) 0.298 Pleural effusion 1 (1.4) 0 (0.0) 1 (2.3) 1.000 Cardiomegaly 4 (5.5) 0 (0.0) 4 (9.1) 0.147 Ed: emergency department; OR: odds ratio; CI: confidence interval; SD: standard deviation; SBP: systolic blood pressure; AST: aspartate amino transferase; ALT: alanine amino transferase; LDH: lactate dehydrogenase; Hb: hemoglobin. presence of lymphopenia is a common characteristic patients with COVID-19. These lymphocytes and of this infection and has been related to more severe their subsets play an important role in the mainte- clinical forms with worse outcomes8-12,25. The reduc- nance and function of the immune system, and their tion of total lymphocytes is also reflected by a reduc- involvement indicates a deterioration of the immune tion in its subsets, and therefore, CD4+ T cells, CD8+ system during the course of SARS-CoV-2 infection, T cells, B cells, and natural killer cells are reduced in which is common to other coronavirus infections such 144 J. Rodríguez et al.: UMC-PNEUMONIA COVID-19 DISCHARGE SAFETY as MERS-CoV and SARS-CoV and indicates greater one of the countries with greater impact of the pan- compromise and severity26,27. In our study, the ab- demic in relation to mortality in Europe. The use of sence of lymphopenia was a predictive variable in the chest X-rays for the diagnosis of COVID-19 pneumo- decision-making for discharge from the ED. While nia may have limited the number of patients with physicians are not especially confident that this bio- pulmonary involvement because of the limited sen- logical marker or indeed, any other analytical param- sitivity of the test, with chest computer tomography eter or inflammatory marker is related to patient (CT) being much more effective in this sense. How- discharge from the ED, the absence of marked lym- ever, not all hospitals could perform CT in all the phopenia could certainly be associated with a less patients suspected of having pneumonia, and neither severe clinical presentation, and as such, is consid- could it be performed in all the patients due to work ered in the final decision. It is to be expected that overload during the peak of the pandemic. There- unilateral radiological involvement would be associ- fore, we believe that our results closely approach the ated with the decision for discharge from the ED. real-life health-care setting of the ED in our country. Although this association was important in the crude Likewise, the use of ultrasound might have helped analysis, it was not confirmed in the adjusted analy- improve the diagnosis of pneumonia, but similar to sis. Chest X-ray is one of the principal complemen- CT, not all EDs are able to perform lung ultrasound tary studies of evaluation in COVID-19, although its in all the patients attended. There may also be a sensitivity is variable based on the days of disease limitation on the results in relation to the number of evolution28. Unilateral radiological involvement is independent variables collected and the number of more related to early phases of the disease and mild events. To minimize this possibility, the variables clinical pictures29. We found no significant differences were grouped into blocks according to their charac- in the duration of the symptoms, although there was teristics. a trend to fewer days of evolution among patients discharged from the ED. Patients with COVID-19 pneumonia had an elevated rate of hospital admission. However, when the deci- An under-researched area is ED return visits in these sion to discharge a patient from the ED was made, it patients. There are currently no prediction models for was safe in terms of mortality but not for EDR30d. ED revisits in patients with COVID-19 infection. In our study, few patients were discharged and many pre- sented EDR30d, although the need for hospital admis- SUPPLEMENTARY DATA sion after EDR30d was low. One positive finding was that the decision for discharge from the ED was safe, The complete members list of the SIESTA Research considering the low mortality in this group. It is likely Group is available as supplementary material. Supple- that the elevated EDR30d was due to the uncertainty mentary data are available at Revista de Investigación and alarm generated by this infection among the Clínica online (10.24875/RIC.22000021). These population in general, together with a clinical picture data are provided by the corresponding author and which produces greater involvement in the general published online for the benefit of the reader. The state of health, myalgias, and different symptomatol- contents of supplementary data are the sole respon- ogy hard to control. It is difficult to predict the EDR30d sibility of the authors. in patients discharged from the ED, making further studies in this scenario necessary, along with the im- plementation of follow-up resources at ED discharge REFERENCES to reduce ED revisits30. 1. Carenzo L, Costantini E, Greco M, Barra FL, Rendiniello V, Mainet- ti M, et al. Hospital surge capacity in a tertiary emergency refer- The main limitation of this study is that it was mul- ral centre during the COVID-19 outbreak in Italy. Anaesthesia. 2020;75:928-34. ticenter, with the inherent heterogeneity this repre- 2. 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