Covid-19 as a paradigmatic model of the heterogeneous disease presentation in older people: data from the GeroCovid Observational study.

Covid-19 may have a heterogeneous onset, especially in older age. However, whether and how Covid-19 signs and symptoms may present and aggregate together according to sociodemographic and health factors is unclear, as well as their prognostic value. This work included 981 Covid-19 inpatients who participated in the GeroCovid Observational study. Signs/symptoms at disease onset, sociodemographic, health, cognitive status, and mobility were systematically recorded. Clusters of signs/symptoms were identified through agglomerative hierarchical clustering. The associations of single signs/symptoms and symptom clusters with longer hospitalization (≥16 days) and in-hospital mortality were explored through logistic and Cox regressions. The signs/symptoms most reported in our sample (age 78.3±9.39 years; 49.4% women) were fever (62.5%), cough (45.5%), and dyspnoea (62.7%). Atypical were reported by up to one-third of patients, and delirium by 9.1%. Atypical symptoms were more frequent with advancing age and with lower pre-Covid-19 cognitive and mobility levels. Older men more likely reported respiratory symptoms than women. Dyspnoea (HR=1.47, 95%CI:1.02-2.12), tachypnea (HR=1.53, 95%CI:1.14-2.07), low oxygen saturation (HR=1.95, 95%CI:1.32-2.88) and delirium (HR=1.60, 95%CI:1.13-2.28) were associated with higher in-hospital mortality. Four symptom clusters were identified. Compared with the mild respiratory symptoms cluster, the severe clinical impairment cluster was associated with higher mortality (HR=2.57, 95%CI:1.58-4.18). The severe clinical impairment and aspecific symptoms clusters were associated with longer hospitalization (OR=2.38, 95%CI:1.56-3.63, and OR=1.75, 95%CI:1.08-2.83, respectively). Multiple health aspects influence Covid-19 clinical presentation. A symptom clusters approach may help predict adverse health outcomes in older patients. In addition to respiratory symptoms, delirium is independently associated with mortality risk.