Clinical characteristics and risk factors for a prolonged length of stay of patients with asymptomatic and mild COVID-19 during the wave of Omicron from Shanghai, China

Abstract

Background This study aims to investigate the clinical characteristics and the length of hospital stay (LOS), as well as risk factors for prolonged LOS in a cohort of asymptomatic and mild COVID-19 patients infected with the Omicron variant. Methods A total of 1166 COVID-19 patients discharged from the inpatient ward of the largest makeshift hospital (May 8–10, 2022) in Shanghai, China, were included. The demographics, medical history, and the lowest and admission cycle threshold (Ct) values of the RT-PCR tests for SARS-CoV-2 genes of the open reading frame 1ab (Ct-ORF) and the nucleocapsid protein (Ct-N) during hospitalization were recorded. Patients with LOS > 7 days, or LOS ≤ 7 days were included in the Prolonged group or the Control group, separately. The clinical characteristics and LOS of the participants in the two groups were described and compared. Multivariate Logistic and linear regression analyses were applied to explore the risk factors for prolonged LOS. The diagnostic efficacy of the lowest and admission Ct values for the Prolonged group was tested via the receiver operating characteristic (ROC) curve analysis. Results The median LOS was 6 days in the total study population. The age was older (45.52 ± 14.78 vs. 42.54 ± 15.30, P = 0.001), while both the lowest and admission Ct-ORF (27.68 ± 3.88 vs. 37.00 ± 4.62, P < 0.001; 30.48 ± 5.03 vs. 37.79 ± 3.81, P < 0.001) and Ct-N (25.79 ± 3.60 vs. 36.06 ± 5.39, P < 0.001; 28.71 ± 4.95 vs. 36.95 ± 4.59, P < 0.001) values were significantly lower in the Prolonged group. There were more mild cases in the Prolonged group (23.8% vs. 11.5%, P < 0.001). The symptom spectrum differed between the two groups. In multivariate analyses, age, disease category, and the lowest Ct-N values were shown to be associated with prolonged LOS. Besides, both the lowest and admission Ct-ORF (AUC = 0.911 and 0.873) and Ct-N (AUC = 0.912 and 0.874) showed robust diagnostic efficacy for prolonged LOS. Conclusions Our study firstly reports the clinical characteristics and risk factors for prolonged LOS during the wave of the Omicron epidemic in Shanghai, China. These findings provide evidence for the early identification of asymptomatic and mild COVID-19 patients at a high risk of prolonged hospitalization who may require early intervention, and long-term monitoring and management.

A retrospective analysis of the influencing factors of nucleic acid CT value fluctuation in COVID-19 patients infected with Omicron variant virus in Changchun city

“…Since nucleic acid CT value fluctuations were positively correlated with hospital stay duration, the patients were further divided into Group A and Group B based on a median hospital stay duration of 10 days. In group A, there were 233 cases in the non-fluctuation group of nucleic acid CT value, including 139 males and 94 females, with a median age of 39 ( 30 , 38 ) years, and 185 cases in the fluctuation group of nucleic acid CT value, including 115 males and 70 females, with a median age of 43 ( 31 , 38 ) years. In group B, there were 427 cases in the non-fluctuation group of nucleic acid CT value, including 249 males and 178 females, with a median age of 39 ( 28 , 38 ) years, and 82 cases in the fluctuation group of nucleic acid CT value, including 47 males and 35 females, with a median age of 34 ( 28 , 39 ) years.…”

“…In group A, there were 233 cases in the non-fluctuation group of nucleic acid CT value, including 139 males and 94 females, with a median age of 39 ( 30 , 38 ) years, and 185 cases in the fluctuation group of nucleic acid CT value, including 115 males and 70 females, with a median age of 43 ( 31 , 38 ) years. In group B, there were 427 cases in the non-fluctuation group of nucleic acid CT value, including 249 males and 178 females, with a median age of 39 ( 28 , 38 ) years, and 82 cases in the fluctuation group of nucleic acid CT value, including 47 males and 35 females, with a median age of 34 ( 28 , 39 ) years. There were no statistically significant differences between the two groups in terms of age, gender composition, vaccination history, medical history, and treatment before admission ( p > 0.05).…”

“…Univariate analysis of nucleic acid CT value fluctuations revealed a significant correlation with hospitalization duration ( z = −12.672, p = 0.000), consistent with previous research that showed a correlation between nucleic acid CT value fluctuations and hospitalization duration ( p = 0.00018, 13). Therefore, nucleic acid CT fluctuations are an important factor related to length of stay ( 38 , 52 ). This suggests a significant correlation between nucleic acid CT value fluctuations and hospitalization duration, and binary logistic regression analysis results indicate a positive correlation between nucleic acid CT value fluctuations and hospital stay duration, indicating that the longer the hospitalization duration, the greater the risk of nucleic acid CT value fluctuations.…”

Single-Facility Analysis of COVID-19 Status of Healthcare Employees during the Eighth and Ninth Pandemic Waves in Japan after Introducing Regular Rapid Antigen Testing

“…Infections caused by the Omicron strain and its derivatives, which have acquired mutations allowing them to evade vaccines [ 12 , 13 , 14 ], do not cause serious illness in the general public but may cause severe infection in older people with comorbidities and those with severe immunodeficiency [ 21 ]. After the sixth wave, infection control measures at medical institutions and nursing homes treating this specific population have become increasingly difficult, and mass infections in elderly welfare facilities and welfare facilities for people with disabilities have increased rapidly [ 10 ].…”