Assistant Professor University of Toronto University of Toronto Toronto, Canada
Background: Nirmatrelvir/ritonavir (Paxlovid) has been approved for use in the treatment of COVID-19. Evaluation of the Real-world effectiveness of nirmatrelvir/ritonavir to prevent hospitalization and death from COVID-19 as variants emerged was needed.
Objectives: To evaluate the real-world effectivness of nirmatrelvir/ritonavir in the prevention of hospitalization and death from COVID-19.
Methods: We conducted a cohort study in Ontario, Canada leveraging administrative health data from ICES. The cohort included all residents >17 years of age who tested positive for SARS-CoV-2 between April 4th and August 31st 2022. We compared nirmatrelvir/ritonavir-treated patients to untreated patients and measured the primary outcome of hospitalization from COVID-19 or all-cause death, and a secondary outcome of death, 1-30 days from the index date. Inverse probability of treatment weighting (IPTW) was used to control for confounding. We used logistic regression models to calculate odds ratios (OR) with 95% confidence intervals (CIs).
Results: The final cohort included 177, 545 patients with 8,876 cases and 168,669 controls. The groups were well-balanced after applying stabilized IPTWs. The relative odds of hospitalization or death, and death in the treated group compared to those untreated was wOR 0.56; 95%CI, 0.47-0.67) and 0.49 (95%CI, 0.39-0.62), respectively. Findings were similar across strata of vaccination status and comorbidities.
Conclusions: This real-world study of Nirmatrelvir/ritonavir found treatment was associated with significantly reduced risk of hospitalization and death. These findings support the ongoing use to treat patients with mild COVID-19 at risk for severe disease.
