Patient-Reported Adverse Events Among Elderly Patients Receiving Novel Oral COVID-19 Antivirals: A Nationwide Sampled Survey in Korea

Background: There is a dearth of research on the factors linked with adverse events (AEs) associated with nirmatrelvir/ritonavir (NMVr) and molnupiravir (MOL), particularly in the elderly. Therefore, this study aimed to investigate self-reported AEs and identify factors associated with the occurrence of AEs following NMVr or MOL treatment among survey participants aged 60 years or older in South Korea. Methods: This nationwide survey was conducted through in-person interviews using structured questionnaires, from July 24 to August 31, 2023. Eligible participants included individuals aged 60 years or older who had been diagnosed with coronavirus disease 2019 (COVID-19) and received NMVr or MOL. The study outcomes included self-reported demographic, lifestyle, and health characteristics associated with the occurrence of AEs. Multivariate logistic regression analysis was used to estimate the adjusted odds ratio (aOR) and 95% confidence interval (CI) of each characteristic in participants with and without AEs. Results: Of the 520 participants, 123 (23.7%) experienced at least one AE with oral COVID-19 treatment: 21.0% (96/458) for NMVr and 43.5% (27/62) for MOL. None of the participants reported any serious AEs. Increased odds of AE occurrence were observed in participants treated with MOL compared to those treated with NMVr (aOR, 3.05; 95% CI, 1.67–5.57), a history of two or more compared to one COVID-19 diagnosis (1.93; 1.03–3.62), and self-reported health status as “Unhealthy” compared to “Healthy” (2.65; 1.31–5.36). Conclusion: No AEs required further evaluation to change treatment strategies in elderly patients on NMVr or MOL. Several factors, including the use of MOL, history of COVID-19, and reported health status, were associated with an increased incidence of AEs. Both treatments may still be useful choices for patients with non-severe COVID-19 aged 60 years or older. However, close monitoring of unidentified potential harm and further investigation of the factors associated with the occurrence of AEs are needed.