Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Adverse effects
RCT	1972 acute and elective inpatients at least 55 years old admitted to vascular, orthopaedic, medical, or care-of-the-elderly wards In review	Proportion of people who were dissatisfied 186/982 (19%) with alternating-pressure mattresses 230/990 (23%) with alternating-pressure mattress overlays	Mean difference 4.4% 95% CI 0.7% to 7.9% P = 0.02	Effect size not calculated	alternating-pressure mattresses