Prevention and Early Treatment of Acute Lung Injury (PETAL) Network – Biology and Longitudinal Epidemiology of PETAL COVID-19 Observational Study (BLUE CORAL)

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Accession Number

Study Type
Epidemiology Study

Collection Type
Open BioLINCC Study See bottom of this webpage for request information

Study Period
June 2020 to March 2022

NHLBI Division

Dataset(s) Last Updated
July 5, 2023

Clinical Trial URLs


Commercial Use Data Restrictions No

Data Restrictions Based On Area Of Research No


To measure the incidence and changes over time in symptoms, disability, and financial status after COVID-19–related hospitalization.


For many individuals, the effects of COVID-19 persist after the acute phase and result in prolonged symptoms and disability. This has led to widespread efforts to characterize the epidemiologic characteristics of such post-COVID-19 sequelae. However, accurate data were limited, hindering the ability to counsel patients, caregivers, and policy makers and to plan relevant recovery-focused clinical research. Thus, the BLUE CORAL study was intended to address the knowledge gaps and provide critical data to help guide clinical care, public health, and scientific efforts.


Participants included English- or Spanish-speaking adults that were hospitalized at one of the 44 PETAL Network hospitals across the U.S. within 14 days of a positive molecular test for SARS-CoV-2 with fever and/or respiratory signs or symptoms compatible with COVID-19. Patients were enrolled within the first 72 hours of hospital admission and were excluded if they had opted for comfort care, were incarcerated, or had severe prehospitalization disabilities or cognitive impairment.

A total of 1388 COVID-19 patents were enrolled, with 825 (444 male, and 379 female) that completed at least one follow-up survey.


BLUE CORAL was a prospective cohort study. Participants were enrolled between August 24, 2020, and July 20, 2021, with follow-up occurring through March 30, 2022. Posthospital surveys were administered by trained interviewers in English or Spanish to patients or their proxies at 1, 3, and 6 months after enrollment. Cardiopulmonary symptoms were assessed using the Airways Questionnaire 20, the Kansas City Cardiomyopathy Questionnaire, and the Seattle Angina Questionnaire. Fatigue was assessed using the Patient Health Questionnaire-9. Disability was assessed by self-report of limitations in activities of daily living (ADLs) or instrumental activities of daily living (IADLs). Financial problems were assessed using the World Health Organization Disability Assessment Schedule 2.0 question and questions regarding job changes, time off work, and insurance coverage developed with the Mi-COVID-19 study using qualitative interviews. Quality of life was measured using the European Quality of Life 5-dimension 5-level instrument.

The primary outcomes were new or worsened cardiopulmonary symptoms, financial problems, functional impairments, perceived return to baseline health, and quality of life. Symptoms that were not present before hospitalization or specifically reported as increased in severity were counted as new or worsened.


The findings of this cohort study of people discharged after COVID-19 hospitalization suggest that recovery in symptoms, functional status, and fatigue was limited at 6 months, and some participants reported new problems 6 months after hospital discharge.

Admon AJ, Iwashyna TJ, Kamphuis LA, Gundel SJ, Sahetya SK, Peltan ID, Chang SY, Han JH, Vranas KC, Mayer KP, Hope AA, Jolley SE, Caldwell E, Monahan ML, Hauschildt K, Brown SM, Aggarwal NR, Thompson BT, Hough CL; National Heart, Lung, and Blood Institute PETAL Network. Assessment of Symptom, Disability, and Financial Trajectories in Patients Hospitalized for COVID-19 at 6 Months. JAMA Netw Open. 2023 Feb 1;6(2):e2255795. doi: 10.1001/jamanetworkopen.2022.55795. PMID: 36787143; PMCID: PMC9929698.

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