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. 2023 Sep;44(9):1458-1466.
doi: 10.1017/ice.2022.300. Epub 2023 Mar 13.

Impact of changing case definitions for coronavirus disease 2019 (COVID-19) hospitalization on pandemic metrics

Claire N Shappell  1   2 , Michael Klompas  1   3 , Christina Chan  1 , Tom Chen  1 , Chanu Rhee  1   3
Affiliations

Impact of changing case definitions for coronavirus disease 2019 (COVID-19) hospitalization on pandemic metrics

Claire N Shappell et al. Infect Control Hosp Epidemiol. 2023 Sep.

Abstract

Objective: To examine the impact of commonly used case definitions for coronavirus disease 2019 (COVID-19) hospitalizations on case counts and outcomes.

Design, patients, and setting: Retrospective analysis of all adults hospitalized between March 1, 2020, and March 1, 2022, at 5 Massachusetts acute-care hospitals.

Interventions: We applied 6 commonly used definitions of COVID-19 hospitalization: positive severe acute respiratory coronavirus virus 2 (SARS-CoV-2) polymerase chain reaction (PCR) assay within 14 days of admission, PCR plus dexamethasone administration, PCR plus remdesivir, PCR plus hypoxemia, institutional COVID-19 flag, or COVID-19 International Classification of Disease, Tenth Revision (ICD-10) codes. Outcomes included case counts and in-hospital mortality. Overall, 100 PCR-positive cases were reviewed to determine each definition's accuracy for distinguishing primary or contributing versus incidental COVID-19 hospitalizations.

Results: Of 306,387 hospital encounters, 15,436 (5.0%) met the PCR-based definition. COVID-19 hospitalization counts varied substantially between definitions: 4,628 (1.5% of all encounters) for PCR plus dexamethasone, 5,757 (1.9%) for PCR plus remdesivir, 11,801 (3.9%) for PCR plus hypoxemia, 15,673 (5.1%) for institutional flags, and 15,868 (5.2%) for ICD-10 codes. Definitions requiring dexamethasone, hypoxemia, or remdesivir selected sicker patients compared to PCR alone (mortality rates 12.2%, 10.7%, and 8.8% vs 8.3%, respectively). Definitions requiring PCR plus remdesivir or dexamethasone did not detect a reduction in in-hospital mortality associated with the SARS-CoV-2 Omicron variant. ICD-10 codes had the highest sensitivity (98.4%) but low specificity (39.5%) for distinguishing primary or contributing versus incidental COVID-19 hospitalizations. PCR plus dexamethasone had the highest specificity (92.1%) but low sensitivity (35.5%).

Conclusions: Commonly used definitions for COVID-19 hospitalizations generate variable case counts and outcomes and differentiate poorly between primary or contributing versus incidental COVID-19 hospitalizations. Surveillance definitions that better capture and delineate COVID-19-associated hospitalizations are needed.

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Conflict of interest statement

Potential Conflicts of Interest

C.R. reports royalties from UpToDate, Inc., and consulting fees from Cytovale and Pfizer on unrelated topics. M.K. reports royalties from UpToDate, Inc. The other authors report no potential conflict of interest.

Figures

Figure 1.
Figure 1.
Crude number of hospitalizations (A), proportion of COVID hospitalizations/PCR positive hospitalizations (B) and in-hospital mortality for COVID hospitalization (C) by month for six candidate definitions of COVID-19 hospitalization
Figure 2.
Figure 2.
Performance of five definitions of COVID-19 hospitalization versus medical record review for Primary and Primary/Contributing COVID Hospitalization
See this image and copyright information in PMC

References

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