Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Healing rates
Systematic review	133 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
Systematic review	20 people, age range 36 to 100 years, acute and long-term care, grade III or IV ulcers	Mean rate of wound closure per week 5% with low-air-loss mattress 9% with air and foam mattress	P value not reported
Systematic review	207 people, mean age 69 years, long-term care, grade III or IV ulcers Data from 1 RCT	Time to complete healing 4.38 months with low-air-loss mattress 4.55 months with specialised foam mattress overlay 3.33 months with alternating pressure	P value not reported
Systematic review	207 people, mean age 69 years, long-term care, grade III or IV ulcers Data from 1 RCT	Mean improvement in Pressure Sore Status Score 18.4 with low-air-loss mattress 34.3 with alternating-pressure mattress	P <0.001	Effect size not calculated	alternating-pressure mattress