A Study to Understand How the Use of Paxlovid Affected Healthcare Use in People With Pre-existing Conditions.

July 21, 2025 updated by: Pfizer

Impact of Nirmatrelvir-ritonavir on Changes in Healthcare Utilization and Frailty Following COVID-19: a Difference-in-difference Analysis

This is a cohort study that will include Paxlovid (nirmatrelvir-ritonavir) treatment eligible for people with a positive SARS-CoV-2 diagnostic test and at least one COVID-19 symptom. This study will look at the change in Post Covid Conditions measured by the number of outpatients, Emergency department, urgent care and inpatient visits before and after COVID-19 between those who did and did not receive Paxlovid. In addition, changes in frailty post-acute infection will be evaluated, in a separate analysis. It is hypothesized that individuals with COVID-19 who received Paxlovid will have a smaller post-COVID-19 increase (vs pre-COVID) in PCC healthcare utilization (i.e., cardiopulmonary) in comparison to patients with COVID-19 who did not receive Paxlovid.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Actual)

14000

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
    • New York
      • New York, New York, United States, 10001
        • Pfizer New York

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Members of the Kaiser Permanente Southern California integrated healthcare delivery system.

Description

Inclusion Criteria:

  • Developed at least one COVID-19 symptom between Apr 1, 2022 through Dec 31, 2023
  • A positive lab-confirmed polymerase chain reaction (PCR) SARS-COV-2 test 5 days after symptom onset (primary analysis).
  • Continuous enrollment in KPSC health plans for at least 1 year (allowing for a 31-day gap to account for potential delays in membership renewal) before the date of symptom onset
  • Active membership in KPSC health plans for at least 31 days after the date of symptom onset
  • Eligible for nirmatrelvir-ritonavir defined by age and CDC-defined risk factors for severe COVID-19

Exclusion Criteria:

  • Individuals on another medication that is contraindicated for treatment with nirmatrelvir-ritonavir defined as having any prescription drug claim in the 90 days prior to COVID-19 symptom onset
  • Receipt of any COVID-19 antiviral (molnupiravir, remdesivir, nirmatrelvir/ritonavir) or monoclonal antibody treatment (bamlanivimab, bebtelovimab, casirivimab/imdevimab, cilgavimab/tixagevimab, otrovimab,) <180 days prior to COVID-19 symptom onset
  • Any positive SARS-CoV-2 test, including self-reported tests, <180 days prior to COVID-19 symptom onset.

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
Participants who received nirmatrelvir-ritonavir
Patients with cardio-pulmonary conditions
Drug: nirmatrelvir-ritonavir
Paxlovid standard of treatment care
Other Names:
  • Paxlovid
Participants who did not received nirmatrelvir-ritonavir
Patients with cardio-pulmonary conditions

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Cardio-pulmonary Measurement A: Change in rate of cardiopulmonary-related healthcare utilization in patients that received nirmatrelvir-ritonavir compared to not received.
Time Frame: 180 days before COVID-19 symptoms to 180 days after or 365 days after
180 days before COVID-19 symptoms to 180 days after or 365 days after

Secondary Outcome Measures

Outcome Measure
Time Frame
Frailty Measurement A: Change in frailty measured by Frailty score Median (IQR) in patients that did receive in patients nirmatrelvir-ritonavir compared to not received.
Time Frame: During Pre-period: 12 months prior to symptom onset Frailty score Median (IQR) to 12 months after.
During Pre-period: 12 months prior to symptom onset Frailty score Median (IQR) to 12 months after.

Collaborators and Investigators

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

Sponsor

Pfizer

Investigators

  • Study Director: Pfizer CT.gov Call Center, Pfizer

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.

Helpful Links

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)

April 15, 2025

Primary Completion (Actual)

April 15, 2025

Study Completion (Actual)

April 15, 2025

Study Registration Dates

First Submitted

July 21, 2025

First Submitted That Met QC Criteria

July 21, 2025

First Posted (Actual)

July 29, 2025

Study Record Updates

Last Update Posted (Actual)

July 29, 2025

Last Update Submitted That Met QC Criteria

July 21, 2025

Last Verified

July 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • C4671067

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

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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