Characteristics and outcomes of COVID-19 patients admitted to hospital with and without respiratory symptoms

Background COVID-19 is primarily known as a respiratory illness; however, many patients present to hospital without respiratory symptoms. The association between non-respiratory presentations of COVID-19 and outcomes remains unclear. We investigated risk factors and clinical outcomes in patients with no respiratory symptoms (NRS) and respiratory symptoms (RS) at hospital admission. Methods This study describes clinical features, physiological parameters, and outcomes of hospitalised COVID-19 patients, stratified by the presence or absence of respiratory symptoms at hospital admission. RS patients had one or more of: cough, shortness of breath, sore throat, runny nose or wheezing; while NRS patients did not. Results Of 178,640 patients in the study, 86.4% presented with RS, while 13.6% had NRS. NRS patients were older (median age: NRS: 74 vs RS: 65) and less likely to be admitted to the ICU (NRS: 36.7% vs RS: 37.5%). NRS patients had a higher crude in-hospital case-fatality ratio (NRS 41.1% vs. RS 32.0%), but a lower risk of death after adjusting for confounders (HR 0.88 [0.83-0.93]). Conclusion Approximately one in seven COVID-19 patients presented at hospital admission without respiratory symptoms. These patients were older, had lower ICU admission rates, and had a lower risk of in-hospital mortality after adjusting for confounders.