Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Healing rates
[9] Systematic review	199 people, mean age 80 years, acute care, grade 1–4 ulcers Data from 1 RCT	Proportion of people with improvement in pressure ulcers 60/83 (72%) with alternating-pressure mattress 56/75 (75%) with fluid mattress overlay	RR 0.97 95% CI 0.80 to 1.17 P = 0.74		Not significant