{Reference Type}: Journal Article
{Title}: Efficacy of COVID-19 Oral antivirals in hospitalised oldest-old with high morbidity burden: a target trial emulation study.
{Author}: Lai FTT;Wang B;Wei C;Chui CSL;Li X;Cheung CL;Wong ICK;Chan EWY;Wan EYF;
{Journal}: Age Ageing
{Volume}: 53
{Issue}: 8
{Year}: 2024 Aug 6
{Factor}: 12.782
{DOI}: 10.1093/ageing/afae180
{Abstract}: <B>BACKGROUND: </B>Molnupiravir and nirmatrelvir-ritonavir are orally administered pharmacotherapies for mild to moderate COVID-19. However, the effectiveness of these drugs among very old (≥80 years), hospitalised patients remains unclear, limiting the risk-benefit assessment of these antivirals in this specific group. This study investigates the effectiveness of these antivirals in reducing mortality among this group of hospitalised patients with COVID-19.<BR><B>METHODS: </B>Using a territory-wide public healthcare database in Hong Kong, a target trial emulation study was conducted with data from 13 642 eligible participants for the molnupiravir trial and 9553 for the nirmatrelvir-ritonavir trial. The primary outcome was all-cause mortality. Immortal time and confounding bias was minimised using cloning-censoring-weighting approach. Mortality odds ratios were estimated by pooled logistic regression after adjusting confounding biases by stabilised inverse probability weights.<BR><B>RESULTS: </B>Both molnupiravir (HR: 0.895, 95% CI: 0.826-0.970) and nirmatrelvir-ritonavir (HR: 0.804, 95% CI: 0.678-0.955) demonstrated moderate mortality risk reduction among oldest-old hospitalised patients. No significant interaction was observed between oral antiviral treatment and vaccination status. The 28-day risk of mortality was lower in initiators than non-initiators for both molnupiravir (risk difference: -1.09%, 95% CI: -2.29, 0.11) and nirmatrelvir-ritonavir (risk difference: -1.71%, 95% CI: -3.30, -0.16) trials. The effectiveness of these medications was observed regardless of the patients' prior vaccination status.<BR><B>CONCLUSIONS: </B>Molnupiravir and nirmatrelvir-ritonavir are moderately effective in reducing mortality risk among hospitalised oldest-old patients with COVID-19, regardless of their vaccination status.