Hospital COVID-19 Surge and Associated Mortality Risk

April 5, 2021 updated by: National Institutes of Health Clinical Center (CC)

Association Between Hospital Case Burden and Mortality Risk Among Patients Hospitalized With COVID-19: A Retrospective Cohort Study of U.S. Hospitals

A retrospective cohort study will be conducted using a large administrative database of U.S. hospitals to understand the volume-outcome relationship among patients hospitalized with COVID-19.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Patients with critical illness and/or respiratory failure tend to display better outcomes at hospitals that manage higher volumes of these patients. However, during a COVID-19 pandemic, this relationship may have been altered by the strain of higher patient volume on resources and personnel. A retrospective cohort study will be conducted using a large administrative database to understand the volume-outcome relationship among patients hospitalized with COVID-19. Understanding the COVID-19 volume-outcome relationship in U.S. hospitals may help identify the optimal care setting and transfer thresholds, and inform triage policies and risk-adjustment.

The Premier Healthcare Database (PHD), an all-payer administrative data repository covering approximately 20% of U.S. hospitalizations from 48 states will be queried for adult (18+ years) in-patient encounters that recorded diagnosis coding for COVID-19 March 1st through August 31st, 2020 at continuously-reporting hospitals. Hospitals with <15 COVID-19 encounters over the study period will be excluded from the primary cohort to preserve statistical reliability.

A surge index will be calculated for each hospital month that incorporates care-complexity-weighted COVID-19 case burden and will be normalized for nominal (2019) bed capacity and non-COVID-19 case burden and will represent the primary covariate. Hospital months will be stratified by the percentile of the surge index (e.g. <50th, 50-75th, 75-90th, 90-95th and ≥95th percentile).

The impact of COVID-19-case burden (surge index) on the risk-adjusted odds ratio (aOR) of mortality (or discharge to hospice) among overall COVID-19 cohorts will be determined using a hierarchical generalized linear mixed model controlling for case-mix, treatment-related, time-varying and other hospital-level factors. Variables will be selected based on their representing "baseline" status upon presentation to the hospital to minimize effect of mediators.

Variables for case mix adjustment: age, gender, race/ethnicity, comorbidity burden, insurance status, admission source and acuity, acute organ failure score and code status present-on-admission, use of pharmacologic agents (remdesivir, corticosteroids, hydroxychloroquine and azithromycin), severity of hypoxia (acute respiratory failure codes, need for non invasive positive pressure ventilation, need for invasive mechanical ventilation), vasopressor use within two days of admission respectively.

Variables for temporal and hospital-level adjustment: hospital teaching status, urbanity, geographic region, bed capacity, hospital proportion of Medicaid/uninsured admissions, proportion of COVID-19 patients intubated within 2 days of admission, hospital's technologic index (stratified by availability of extracorporeal membrane oxygenation, more than one ICU and continuous renal replacement therapy), hospital availability of remdesivir, attending physician to patient ratio, pre-COVID-19 mechanical ventilation volume, proportion of overall admits tested for COVID-19 and admission month (1st vs 2nd wave).

Effect modification by (1st vs. 2nd ) pandemic wave, the previous month's surge index and rate of acute hospital transfers and/or tracheotomies will assessed using interaction terms. Sensitivity analyses will be performed using alternative iterations/strata of the surge index, excluding fewer patients for statistical reliability, models with and without treatment-related variables and using Elixhauser comorbidity index instead of US Centers for Disease Control and Prevention-defined poor prognostic underlying conditions in COVID-19 to test robustness of results. Analyses will be repeated using in-hospital mortality (without reported discharges to hospice). The magnitude of an unmeasured confounder that would be necessary to alter the direction of statistically significant findings will be assessed. More selective subgroups of patients in ICU and mechanical ventilation will not be used as a primary study population given the potentially dynamic nature of admission and intubation criteria over the course of the pandemic and its relationship to volume.

Depending on availability at the time of analysis, an de-identified curated electronic health record-based dataset will be used for clinical validation of select variables in administrative data (e.g. reliability of respiratory failure codes in representing patients requiring high-flow oxygen alone i.e. not non-invasive or invasive mechanical ventilation.)

Study Type

Observational

Enrollment (Actual)

144116

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • National Institutes of Health Clinical Center (primary center conducting large database study)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

See study description

Description

Inclusion Criteria:

  • See study description

Exclusion Criteria:

  • See study description

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Inpatient encounters with COVID-19 present-on-admission
See Study description above
Other: Surge Index
See study description above

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
In-hospital mortality or discharge to hospice
Time Frame: From time of admission to death during the hospitalization or discharge to hospice
From time of admission to death during the hospitalization or discharge to hospice

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
In-hospital mortality
Time Frame: From time of admission to death during the hospitalization
(without reported discharges to hospice)
From time of admission to death during the hospitalization

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Institutes of Health Clinical Center (CC)

Collaborators

Harvard Medical School (HMS and HSDM)
National Cancer Institute (NCI)
National Institute of Allergy and Infectious Diseases (NIAID)
Emory University

Investigators

  • Principal Investigator: Sameer S Kadri, MD, MS, National Institutes of Health, Clinical

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 1, 2020

Primary Completion (Actual)

February 15, 2021

Study Completion (Actual)

February 15, 2021

Study Registration Dates

First Submitted

December 28, 2020

First Submitted That Met QC Criteria

December 28, 2020

First Posted (Actual)

December 30, 2020

Study Record Updates

Last Update Posted (Actual)

April 6, 2021

Last Update Submitted That Met QC Criteria

April 5, 2021

Last Verified

December 1, 2020

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • BD022386

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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