Patients, setting and human ethical approvals
This retrospective observational study, conducted at the Shanghai Geriatric Medical Center (Meilong Branch of Zhongshan Hospital, Fudan University), examined individuals with COVID-19 who were hospitalized from 26th April to 30th June 2022. The Shanghai Geriatric Medical Center is a specialized medical facility that admits patients with COVID-19 in Shanghai for treatment. The omicron sublineage BA.2.2 was the primary cause of COVID-19 cases reported in Shanghai during this time frame[16].
Patients admitted for SARS-CoV-2 burden rebound were excluded if they had one RT-PCR test during their hospitalization and the result is negative, a severe COVID-19 diagnosis upon hospitalization, or insufficient information in the electronic medical record. The patient’s infection severity was categorized based on the Diagnosis and Treatment Guideline for COVID-19 (Trial Version 9) issued by the China National Health Commission[12]. Mild COVID-19 refer to individuals experiencing one or multiple mild symptoms such as pyrexia, tussis, pharyngitis, asthenia, myalgia, anosmia and no concomitant pneumonia. Patients with moderate COVID-19 exhibit symptoms similar to those with mild disease, but they also show radiologic signs of pneumonia. The high-risk group for severe COVID-19 includes individuals aged 60 years or older who have a medical history of hypertension, cardiovascular diseases, cerebral infarction, chronic liver or kidney diseases, cancers, smoking, or obesity[13-15]. This analysis only included individuals who were diagnosed with mild or moderate cases of COVID-19 and were deemed to be at a high risk of developing severe illnesses. Patients were excluded if they had contraindications to nirmatrelvir-ritonavir, severe renal impairment (estimated glomerular filtration rate [eGFR] <30 mL/min per 1.73 m², undergoing dialysis, or had undergone renal transplantation), or severe liver impairment (cirrhosis, hepatocellular carcinoma, or had undergone liver transplantation).
This study adhered to STROBE guidelines and received approval from the ethics committees of Zhongshan Hospital, Fudan University (approval number B2022-470R). Due to the exceptional circumstances of the COVID-19 outbreak, this retrospective study utilizing de-identified information did not necessitate individual patient-informed consent.