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

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.

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.