The Impact of Nirmatrelvir-Ritonavir in Reducing Hospitalizations Among High-Risk Patients With SARS-CoV-2 During the Omicron Predominant Era.

Background: The coronavirus disease 2019 (COVID-19) pandemic has caused significant morbidity and mortality in high-risk populations. Several therapeutics have been developed to reduce the risk of complications related to COVID-19, hospitalizations, and death. In several studies, nirmatrelvir-ritonavir (NR) was reported to reduce the risk of hospitalizations and death. We aimed to evaluate the efficacy of NR in preventing hospitalizations and death during the Omicron predominant period.

Methods: We retrospectively evaluated patients from June 1, 2022, through September 24, 2022. There were a total of 25,939 documented COVID-19 cases. Using propensity matching, we matched 5754 patients treated with NR with untreated patients.

Results: Postmatching, the median age of the NR-treated group was 58 years (interquartile range, 43-70 years) and 42% were vaccinated. Postmatching composite outcome of the 30-day hospitalization and mortality in the NR-treated group were 0.9% (95% confidence interval [CI]: 0.7%-1.2%) versus 2.1% (95% CI: 1.8%-2.5%) in the matched control group, with a difference of -1.2 (-1.7, -0.8), P value <.01. The difference rates (NR vs. control) in 30-day all-cause hospitalizations and mortality were -1.2% (95% CI: -1.6% to -0.7%, P value <.01) and -0.1% (95% CI: -0.2% to 0.0%, P value = 0.29), respectively. We found similar finding across different age groups (≥65 vs. <65) and the vaccinated group.

Conclusion: We report a significant benefit with the use of NR in reducing hospitalizations among various high-risk COVID-19 groups during the Omicron BA.5 predominant period.