Site of care and factors associated with mortality in unvaccinated Australian aged care residents during COVID-19 outbreaks

Background: Residential InReach presents an alternative to hospital admission for aged care residents swabbed for coronavirus disease 2019 (COVID-19), although relative outcomes remain unknown.

Aims: To compare rates and predictors of 28-day mortality for aged care residents seen by InReach with COVID-19, or 'suspected COVID-19' (sCOVID), including hospital versus InReach-based care.

Methods: Prospective observational study of consecutive patients referred to a Victorian InReach service meeting COVID-19 testing criteria between April and October 2020 (prevaccine availability). COVID-19 was determined by positive polymerase chain reaction testing on nasopharyngeal swab. sCOVID-19 was defined as meeting symptomatic Victorian Government testing criteria but persistently swab negative.

Results: There were no significant differences in age, sex, Clinical Frailty Score (CFS) or Charlson Comorbidity Index (CCI) between 152 patients with COVID-19 and 118 patients with sCOVID. Similar results were found for 28-day mortality between patients with COVID-19 (35/152, 23%) and sCOVID (32/118, 27%) (P = 0.4). For the combined cohort, 28-day mortality was associated with initial oxygen saturation (P < 0.001), delirium (P < 0.001), hospital transfer for acuity (P = 0.02; but not public health/facility reasons), CFS (P = 0.04), prior ischaemic heart disease (P = 0.01) and dementia (P = 0.02). For patients with COVID-19, 28-day mortality was associated with initial oxygen saturation (P = 0.02), delirium (P < 0.001) and hospital transfer for acuity (P = 0.01), but not public health/facility reasons.

Conclusion: Unvaccinated aged care residents meeting COVID-19 testing criteria seen by InReach during a pandemic experience high mortality rates, including with negative swab result. Residents remaining within-facility (with InReach) experienced similar adjusted mortality odds to residents transferred to hospital for public health/facility-based reasons, and lower than those transferred for clinical acuity.