COVID-19: a retrospective cohort study with focus on the over-80s and hospital-onset disease

Data from the UK COVID-19 outbreak are emerging, and there are ongoing concerns about a disproportionate effect on ethnic minorities. There is very limited information on COVID-19 in the over-80s, and the rates of hospital-onset infections are unknown.

This was a retrospective cohort study from electronic case records of the first 450 patients admitted to our hospital with PCR-confirmed COVID-19, 77% of the total inpatient caseload to date. Demographic, clinical and biochemical data were extracted. The primary endpoint was death during the index hospital admission. The characteristics of all patients, those over 80 years of age and those with hospital-onset COVID-19 were examined.

The median (IQR) age was 72 (56, 83), with 150 (33%) over 80 years old and 60% male. Presenting clinical and biochemical features were consistent with those reported elsewhere. The ethnic breakdown of patients admitted was similar to that of our underlying local population. Inpatient mortality was high at 38%. Patients over 80 presented earlier in their disease course and were significantly less likely to present with the typical features of cough, breathlessness and fever. Cardiac co-morbidity and markers of cardiac dysfunction were more common, but not those of bacterial infection. Mortality was significantly higher in this group (60% vs 28%, p < 0.001). Thirty-one (7%) patients acquired COVID-19 having continuously been in hospital for a median of 20 (14, 36) days. The peak of hospital-onset infections occurred at the same time as the overall peak of admitted infections. Despite being older and more frail than those with community-onset infection, their outcomes were no worse.

Inpatient mortality was high, especially among the over-80s, who are more likely to present atypically. The ethnic composition of our caseload was similar to the underlying population. While a significant number of patients acquired COVID-19 while already in hospital, their outcomes were no worse.