COVID-19 oral antivirals reduce hospitalization and inpatient progression in nursing home residents

A territory-wide, retrospective cohort study in Hong Kong has shown that molnupiravir and nirmatrelvir/ritonavir are effective in reducing the risks of hospitalization and inpatient disease progression among older patients residing in nursing homes.

“The results highlight the clinical benefits [of molnupiravir and nirmatrelvir/ritonavir] in managing COVID-19 outbreaks in nursing homes, supporting the use of oral antivirals in elderly patients in this setting,” said Dr Bosco Ma of Department of Medicine and Therapeutics, the Chinese University of Hong Kong.

The study included 14,617 nursing home residents (mean age, 84.8 years; male, 43.8 percent) with confirmed COVID-19 between 16 February and 31 March 2022. At baseline, 76.9 percent of the patients had cardiovascular diseases, with hypertension being the most common (75.4 percent). Other common comorbidities included diabetes (36.3 percent), gastrointestinal diseases (13.5 percent), nervous system diseases (16.0 percent), and respiratory diseases (11.3 percent). [JAMA Netw Open 2023;6:e2310887]

In the study cohort, 8,939 patients (61.2 percent) did not receive oral antivirals, while 5,195 patients (35.5 percent) received molnupiravir and 483 patients (3.3 percent) received nirmatrelvir/ritonavir. Compared with nonusers, oral antiviral users consisted of a lower proportion of men, and had fewer comorbidities and fewer hospitalizations in the past year. However, gender distribution and comorbidity rates were similar between users of molnupiravir and nirmatrelvir/ritonavir.

Over a median follow-up of 30 days, the primary endpoint of hospitalization for COVID-19 occurred in 42.6 percent of patients (oral antiviral nonusers, 59.6 percent; molnupiravir users, 16.0 percent; nirmatrelvir/ritonavir users, 12.4 percent), while 15.8 percent of patients (oral antiviral nonusers, 23.5 percent; molnupiravir users, 3.8 percent; nirmatrelvir/ritonavir users, 1.0 percent) experienced inpatient disease progression (ie, admission to intensive care unit, use of invasive mechanical ventilation and/or death).

After propensity score weighting to adjust for differences in baseline characteristics, the use of either molnupiravir or nirmatrelvir/ritonavir was associated with significantly reduced risks of hospitalization (molnupiravir: weighted hazard ratio [wHR], 0.46; 95 percent confidence interval [CI], 0.37–0.57; p<0.001) (nirmatrelvir/ritonavir: wHR, 0.46; 95 percent CI, 0.32–0.65; p<0.001) and inpatient disease progression (molnupiravir: wHR, 0.35; 95 percent CI, 0.23–0.51; p<0.001) (nirmatrelvir/ritonavir: wHR, 0.17; 95 percent CI, 0.06–0.44; p<0.001) vs nonuse of oral antivirals. However, no significant differences were found for these risks between molnupiravir and nirmatrelvir/ritonavir use (hospitalization, p=0.99; inpatient disease progression, p=0.12).

In Cox regression analysis, molnupiravir showed a 65 percent decrease in risk of hospitalization (adjusted HR [aHR], 0.35; 95 percent CI, 0.32–0.38), and nirmatrelvir/ritonavir demonstrated a risk decrease of 69 percent (aHR, 0.31; 95 percent CI, 0.24–0.41). For inpatient disease progression, molnupiravir showed a 62 percent risk reduction (aHR, 0.38; 95 percent CI, 0.33–0.45), while nirmatrelvir/ritonavir showed an 86 percent risk reduction (aHR, 0.14; 95 percent CI, 0.06–0.35).

“These findings could be extrapolated to frail elderly patients living in the community,” the researchers commented.