So, What If Something Happens (SWISH): an International Multi-centre Retrospective Cohort Study of Escalations Back to Hospital during Hospital at Home Admissions

Importance Hospital-at-home (HaH) delivers effective acute care at home for patients who would otherwise require hospitalisation. As HaH programs expand, there is a need to standardise quality metrics, specifically regarding timely response to deterioration resulting in hospital escalation. Objective This study proposes a standardised definition of unplanned escalation as a primary safety outcome, exploring escalation rates, causes, and associated risk factors across 3 international sites. Design A multi-centre retrospective cohort study was conducted from January to December 2023. Setting The study was conducted across Epworth Hospital (Australia), Mass General Brigham (USA), and National University Health System (Singapore). Participants In a cohort of 3,114 HaH patients, the median age was 62.5 in EPW, 70 in MGB and 61 in NUHS. The proportion of males overall was 44.8%. 76.75% were from lower socioeconomic status, 64.26% were referred from the general ward and 89.21% were from the medicine service. Exposure Admission to a HaH program providing hospital-level acute care in the patient’s home. Outcomes The primary outcome was unplanned escalation. Secondary outcomes included escalations and mortality before or after escalation. Results Unplanned escalation rates were consistent across sites (6.1–6.5%), mostly due to deterioration of existing conditions. Regression analysis revealed that age <65 compared to those 85 and older was associated with significantly lower risk of unplanned escalation (OR 0.61, 95% CI 0.38-0.96). Comorbidities of diabetes (OR 1.39, 95% CI 1.02-1.9) and stroke (OR 1.76, 95% CI 1.1-2.6) were associated with higher risk of escalation. Most unplanned returns went through emergency departments, except at Epworth, where direct ward transfers were more common. Conclusion Unplanned escalation rates in HaH units were consistent at between 6-7% suggesting an internal benchmark for acceptable risk. ICU admissions (1.99%) and mortality (4.33%) following escalation were low. This study advances the utility of unplanned escalation as a HaH safety measure.