Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Healing rates
[7] Systematic review	People 2 RCTs in this analysis	Healing rate with low-air-loss beds with convoluted foam Absolute results not reported	RR 1.25 95% CI 0.84 to 1.86 The meta-analysis may have been underpowered to detect a clinically important difference between groups		Not significant
[8] [9] Systematic review	20 people, age range 36–100 years, acute and long-term care, grade 3 or 4 ulcers Data from 1 RCT	Mean rate of wound closure per week 5% with low-air-loss mattress 9% with air and foam mattress	P value not reported It was reported that data were insufficient to calculate the difference in mean rates of ulcer healing between the 2 interventions It was unclear how many ulcers achieved healing