The following is a summary of “Identifying Veterans Who Benefit From Nirmatrelvir-Ritonavir: A Target Trial Emulation,” published in the June 2024 issue of Infectious Disease by Yan et al.

While recommended for individuals at risk of severe COVID-19, nirmatrelvir-ritonavir is currently underused, highlighting the need for data on its practical application across eligible groups.

Researchers conducted a retrospective study determining effective eligibility criteria for optimizing nirmatrelvir-ritonavir utilization among high-risk individuals for severe COVID-19.

They conducted an emulation study within the Veterans Health Administration, comparing outcomes between veterans at high risk for severe COVID-19 who tested positive for SARS-CoV-2 and received nirmatrelvir–ritonavir (April 2022 to March 2023). The outcome measures included incidence of hospitalization or all-cause mortality at 30 days, evaluated across the entire cohort and stratified by estimated 30-day risk of death or hospitalization using an ensemble risk prediction model.

The results showed 87% male with a median age of 66 years and 16% unvaccinated and were treated with nirmatrelvir-ritonavir (n = 24,205) experienced lower 30-day risks of hospitalization (1.80% vs. 2.30%; risk difference [RD], −0.50% [95% CI: −0.69 to −0.35]) and death (0.11% vs. 0.30%; RD, −0.20 [95% CI: −0.24 to −0.13]) compared to matched untreated individuals. Significant reductions in combined hospitalization or death were particularly in the highest risk quartile (RD −2.85 [95% CI: −3.94 to −1.76]), immunocompromised individuals (RD −1.91 [95% CI: −3.09 to −0.74]), and individuals aged 75 years and older (RD −1.16 [95% CI: −1.73 to −0.59]). In contrast, no reductions were noted in the two lowest-risk quartiles or patients under 65 years of age regarding the risk of hospitalization or death.

Investigators concluded that nirmatrelvir-ritonavir significantly reduced 30-day hospitalization and death in high-risk, older, and immunocompromised veterans but showed no benefit for younger or lower-risk groups.

Source: academic.oup.com/cid/advance-article/doi/10.1093/cid/ciae202/7691167