The proportion of patients meeting clinical practice guidelines compares favorably to similar studies. In some cases, patients' clinical conditions or unit HOB angle protocol explained not meeting guidelines. However, there were cases where reasons for not meeting guidelines were unknown.

Recruitment of sufficient participants to randomised controlled trials (RCTs) is widely acknowledged to present considerable challenges, unique to the context of the research area. This study considers factors affecting recruitment to a multi-centred RCT investigating the effectiveness of geriatrician-led 'hospital at home' for older people living with frailty, compared with acute inpatient care [1]. Participating sites in the RCT are shown in Figure 1 and key recruitment processes are shown in Figure 2. Comprehensive Geriatric Assessment in hospital or at home? The role of clinician uncertainty in recruitment to a randomised controlled trial