JMIR Publications

ABSTRACT

Background:

Older adults have worse outcomes following hospitalisation with COVID-19, but within this group there is substantial variation. Although frailty and comorbidity are key determinants of mortality, it is less clear which manifestations of frailty and comorbidity are associated with the worst outcomes.

Objective:

We aimed to identify the key comorbidities and domains of frailty that were associated with in-hospital mortality in older patients with COVID-19.

Methods:

This was a retrospective study that used the Hospital Episode Statistics administrative dataset from 1st March 2020 to 28th February 2021 for hospital patients in England aged 65 years and over. Frailty was assessed using the Dr Foster Global Frailty Scale (GFS) and comorbidity using the Charlson Comorbidity Index (CCI). Descriptive statistics techniques were used to determine mortality rates according to the demographic, frailty and comorbidity profile of patients. Features were selected, pre-processed and inputted into a random forest classification algorithm to predict in-hospital mortality.

Results:

In total 215,831 patients were included. The frailty and comorbidity measures significantly improved the model’s ability to predict mortality in patients, when used alongside age, sex, deprivation, ethnicity, discharge month and year, region, disease severity and hospital trust. The most important frailty items in the GFS were dementia/delirium, falls/fractures and pressure ulcers/weight loss. The most-important comorbidity items in the CCI were cancer, heart failure and renal disease. The best-performing model had a predictive accuracy of 82% as well as an area under the curve of 0.90 and the features included all the aforementioned covariates.

Conclusions:

The physical manifestation of frailty and comorbidity, particularly a history of cognitive impairment and falls, may be useful in identification of patients who may need additional support during hospitalisation.