Hospitals are efficiency-oriented and often fail to adequately accommodate anything more than the most basic needs of their patients. This applies especially to patients with dementia because of their particular vulnerability to further functional decline during a hospital stay, as normal day-to-day activities atrophy very quickly when they are paused. In acknowledging this problem, Special Care Units (SCUs) have been developed especially to treat patients with dementia while in hospitals. SCUs are intended to work on several levels, including the model of care, comprehensive integration with the hospital at large etc. but our interest is in dementia-friendly design, because whether these measures affect outcomes has hitherto not been quantified. Using multilevel regression analysis, looking at the spatial data from 25 German SCUs alongside retrospective routine data from geriatric patients (N = 2735), it was revealed that most dementia-friendly design measures are associated with significant improvement in patients’ self-care abilities. The design measures proved to be effective, feasible and attractive. This paper outlines the potential of dementia-friendly design to shift from speciality design towards human-centred design for the entire general hospital.