What is the evidence base for ambulatory care for acute medical illness?

Acute ambulatory care is a critical component of the emergency care pathway with national policy support and a dedicated NHS Improvement network. The evidence base for treating acute medical illness outside hospital is a diverse mix of randomised and observational studies with varying inclusion criteria, prognostic stratification, interventions and healthcare setting which limits synthesis of all available evidence and translation to the UK context. There is little consensus on the level of risk for home-based treatment for acute medical illness. Selection tools for referral to acute ambulatory care have been developed but there is limited evidence for their use. There are still research questions concerning optimal staffing, referral mechanisms, point of care diagnostic portfolio and tools for shared decision making.