A wide range of patient benefits have been attributed to single room hospital accommodation including a reduction in adverse patient safety events. However, studies have been limited to the US with limited evidence from elsewhere. The aim of this study was to assess the impact on safety outcomes of the move to a newly built all single room acute hospital.

A natural experiment investigating the move to 100% single room accommodation in acute assessment, surgical and older people’s wards. Move to 100% single room accommodation compared to ‘steady state’ and ‘new build’ control hospitals. Falls, pressure ulcer, medication error, meticillin-resistant Staphylococcus aureus and Clostridium difficile rates from routine data sources were measured over 36 months.

Five of 15 time series in the wards that moved to single room accommodation revealed changes that coincided with the move to the new all single room hospital: specifically, increased fall, pressure ulcer and Clostridium difficile rates in the older people’s ward, and temporary increases in falls and medication errors in the acute assessment unit. However, because the case mix of the older people’s ward changed, and because the increase in falls and medication errors on the acute assessment ward did not last longer than six months, no clear effect of single rooms on the safety outcomes was demonstrated. There were no changes to safety events coinciding with the move at the new build control site.

For all changes in patient safety events that coincided with the move to single rooms, we found plausible alternative explanations such as case-mix change or disruption as a result of the re-organization of services after the move. The results provide no evidence of either benefit or harm from all single room accommodation in terms of safety-related outcomes, although there may be short-term risks associated with a move to single rooms.