Interventions versus comparators (included reviews; the number of studies with total participants)	Care setting	Relative effect (RR, 95% CI)	Anticipated absolute effect (95% CI)			Certainty of evidence	Interpretation of findings
			Risk with comparators	Risk with interventions	Difference
Pressure ulcer incidence
Alternating pressure (active) air surfaces versus foam surfaces (Shi 2021a; Shi 2021b; 4 RCTs with 2247 participants)	Acute and long‐term care settings	RR 0.63, 0.34 to 1.17	104 per 1000	66 per 1000 (35 to 122)	38 fewer per 1000 (69 fewer to 18 more)	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for moderate imprecision)	Alternating pressure (active) air surfaces may reduce the number of incident pressure ulcer compared with foam surfaces; however, the evidence is low certainty.
Alternating pressure (active) air surfaces versus reactive air surfaces (Shi 2021a; Shi 2021c; 6 RCTs with 1648 participants)	Acute and long‐term care settings	RR 1.61, 0.90 to 2.88	22 per 1000	36 per 1000 (20 to 64)	14 more per 1000 (2 fewer to 42 more)	⊕⊝⊝⊝ VERY LOW (downgraded twice for high risk of bias and once for moderate imprecision)	It is uncertain if the proportion of people developing a new pressure ulcer is decreased or increased when alternating pressure (active) air surfaces are compared with reactive air surfaces.
Alternating pressure (active) air surfaces versus reactive water surfaces (Shi 2021a; Shi 2021d; 2 RCTs with 358 participants)	Acute and long‐term care settings	RR 1.21, 0.52 to 2.83	52 per 1000	63 per 1000 (27 to 148)	11 more per 1000 (25 fewer to 96 more)	⊕⊝⊝⊝ VERY LOW (downgraded twice for high risk of bias and twice for substantial imprecision)	It is uncertain if the proportion of people developing a new pressure ulcer is decreased or increased when alternating pressure (active) air surfaces are compared with reactive water surfaces.
Alternating pressure (active) air surfaces versus reactive fibre surfaces (Shi 2021a; Shi 2021d; 3 RCTs with 285 participants)	Acute care setting	RR 0.90, 0.68 to 1.19	424 per 1000	381 per 1000 (288 to 504)	43 fewer per 1000 (136 fewer to 80 more)	⊕⊝⊝⊝ VERY LOW (downgraded twice for high risk of bias and once for imprecision).	It is uncertain if the proportion of people developing a new pressure ulcer is decreased or increased when alternating pressure (active) air surfaces are compared with reactive fibre surfaces.
Alternating pressure (active) air surfaces on operating tables and subsequently on ward beds versus reactive gel surfaces used in operating room followed by foam surfaces used on ward bed (Shi 2021a; Shi 2021d; 2 RCTs with 415 participants)	Operating room	RR 0.22, 0.06 to 0.76	68 per 1000	15 per 1000 (4 to 52)	53 fewer per 1000 (64 fewer to 16 more)	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for imprecision)	Alternating pressure (active) air surfaces applied on both operating tables and hospital beds may reduce the proportion of people developing a new pressure ulcer compared with reactive gel surfaces used on operating tables followed by foam surfaces applied on hospital beds.
Comparison between two types of alternating pressure (active) air surfaces (Shi 2021a; seven studies with 2833 participants)	Acute and long‐term care settings	None of the seven studies showed a difference in the proportion of people with incident pressure ulcers between different types of alternating pressure (active) air surfaces.	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for imprecision)	There may be little to no difference in the proportion of people with incident pressure ulcers between different types of alternating pressure (active) air surfaces.
Alternating pressure (active) air surfaces versus undefined 'standard hospital surfaces' (Shi 2021a; 4 RCTs with 830 participants)	Acute and long‐term care settings	All four studies consistently showed that alternating pressure (active) air surfaces could reduce the proportion of participants developing a new pressure ulcer compared with the undefined 'standard hospital surfaces'.	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded twice for risk of bias)	Alternating pressure (active) air surfaces may reduce the proportion of participants developing a new pressure ulcer compared with undefined standard hospital surfaces.
Foam surfaces versus reactive air surfaces (Shi 2021b; Shi 2021c; 4 RCTs with 229 participants)	Acute and long‐term care settings	RR 2.40, 1.04 to 5.54	106 per 1000	255 per 1000 (110 to 588)	149 more per 1000 (4 more to 482 more)	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for imprecision)	Foam surfaces may increase the proportion of participants developing a new pressure ulcer compared with reactive air surfaces.
Foam surfaces versus reactive fibre surfaces (Shi 2021b; Shi 2021d; one RCT with 68 participants)	Acute care setting	RR 1.17, 0.64 to 2.14	353 per 1000	413 per 1000 (226 to 755)	60 more per 1000 (127 fewer to 402 more)	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias, and once for imprecision).	It is uncertain if there is a difference in the proportion of participants developing a new pressure ulcer between foam surfaces with reactive fibre surfaces.
Foam surfaces versus reactive gel surfaces (Shi 2021b; Shi 2021d; one RCT with 135 participants)	Operating room	One study involving a totality of 135 individuals (270 halves of bodies) indicated no pressure ulcers developed in either group.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias, and twice for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new pressure ulcer between foam surfaces and reactive gel surfaces.
Foam surfaces versus reactive foam and gel surfaces (Shi 2021b; Shi 2021d; one RCT with 91 participants)	Operating room	One study compared foam surfaces and reactive foam and gel surfaces in 91 participants (with 182 halves of bodies) using a split body design and found no pressure ulcers developed in either group.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias, and twice for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new pressure ulcer between foam surfaces and reactive foam and gel surfaces.
Foam surfaces versus reactive water surfaces (Shi 2021b; Shi 2021d; one RCT with 117 participants)	Acute care setting	One RCT with 117 participants did not report any outcomes that were directly relevant to this review and so none of its data were analysable.	Not applicable	Not applicable	Not applicable	Not applicable	Not applicable
Foam surfaces versus other types of foam surfaces (Shi 2021b; six RCTs with 733 participants)	Acute and long‐term care setting	The six studies reported heterogeneous ulcer incidence data between studies and data are hard to interpret.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, twice for heterogeneity and once for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new pressure ulcer between two types of foam surface.
Foam surfaces versus undefined surfaces (Bedcare; Shi 2021b; one RCT with 206 participants)	Long‐term care setting	RR 0.56, 0.19 to 1.60	87 per 1000	49 per 1000 (17 to 140)	38 fewer per 1000 (70 fewer to 53 more)	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and twice for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new pressure ulcer between foam surfaces and undefined reactive surfaces.
Foam surfaces versus undefined standard hospital surfaces (Shi 2021b; eight studies with 4066 participants)	Acute care setting	Eight studies reported inconsistent results: five (3485 participants) reported no difference in the proportion of participants developing a new pressure ulcer between groups; two (168 participants) suggested foam surfaces reduced the risk of having new pressure ulcers; one (413 participants) suggested foam surfaces increased the risk.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, and twice for inconsistency)	It is uncertain if there is a difference in the proportion of participants developing a new pressure ulcer between foam surfaces and undefined standard hospital surfaces.
Reactive air surfaces versus reactive water surfaces (Shi 2021c; Shi 2021d; one RCT with 37 participants)	Intensive care unit	RR 0.43, 0.04 to 4.29	118 per 1000	51 per 1000 (5 to 505)	67 fewer per 1000 (113 fewer to 387 more)	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, and twice for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new ulcer between reactive air surfaces and reactive water surfaces.
Reactive air surfaces versus reactive gel surfaces (Shi 2021c; Shi 2021d; one RCT with 66 participants)	Long‐term care setting	RR 1.25, 0.56 to 2.77	242 per 1000	302 per 1000 (136 to 670)	60 more per 1000 (106 fewer to 428 more)	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, and twice for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new ulcer between reactive air surfaces and reactive gel surfaces.
Reactive foam and gel surfaces versus reactive gel surfaces (Shi 2021d; one RCT with 166 participants)	Operating room	The only study reported no pressure ulcers developed.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and once for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new pressure ulcer between reactive foam and gel surfaces and reactive gel surfaces.
Reactive air surfaces versus another type of reactive air surfaces (Shi 2021c; two studies with 223 participants)	Acute care setting	Neither study found a difference in the proportions of participants developing a new pressure ulcer between two different brands (EHOB and KinAir) of reactive air surface or between another two different brands (Sofflex and Roho) of reactive air surface.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias and twice for imprecision)	It is uncertain if there is a difference in the proportions of participants developing a new pressure ulcer between two different brands (EHOB and KinAir) of reactive air surface or between another two different brands (Sofflex and Roho) of reactive air surface.
Reactive air surfaces versus undefined surfaces (alternating pressure (active) air surfaces or RIK microfluid static overlay) (Shi 2021c; one RCT with 110 participants)	Acute care setting	RR 0.33, 0.07 to 1.58	109 per 1000	36 per 1000 (8 to 172)	73 fewer per 1000 (101 fewer to 63 more)	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and twice for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new ulcer between reactive air surfaces and undefined reactive surfaces.
Reactive air surfaces versus undefined standard hospital surfaces (Shi 2021c; two RCTs with 216 participants)	Acute care setting	Two studies (216 participants) reported inconsistent results: one study (116 participants) suggested no difference in the proportion of participants developing a new ulcer between groups whilst another study (100 participants) suggested reactive air surfaces reduced the risk of having new pressure ulcers (RR 0.21, 95% CI 0.07 to 0.70).	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, twice for inconsistency and twice for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new ulcer between reactive air surfaces and standard hospital surfaces.
Reactive water surfaces versus undefined 'standard hospital surfaces' (Shi 2021d; one RCT with 316 participants)	Acute care setting	RR 0.35, 0.15 to 0.79	130 per 1000	46 per 1000 (20 to 103)	84 fewer per 1000 (110 fewer to 27 fewer)	⊕⊕⊝⊝ LOW (downgraded twice for risk of bias)	Reactive water surfaces may reduce the proportion of participants developing a new pressure ulcer compared with undefined standard hospital surfaces.
Reactive gel surfaces versus undefined 'standard hospital surfaces' (Shi 2021d; two RCTs with 446 participants)	Operating room	One study reported that reactive gel surfaces significantly reduced the incidence rates of sacral pressure ulcers compared with standard hospital surfaces (P = 0.01). Another study reported 10.7% (22/205) of people using reactive gel surfaces developed new pressure ulcers and the proportion was 20.4% (43/211) for those using standard hospital surfaces (RR 0.53, 95% CI 0.33 to 0.85).	No pooling	No pooling	No pooling	⊕⊕⊕⊝ MODERATE (downgraded once for risk of bias)	Reactive gel surfaces probably reduce the proportion of participants developing a new pressure ulcer.
Reactive gel surfaces versus undefined surfaces (Aiartex; Shi 2021d; two RCTs with 122 participants)	Long‐term care setting	Of the two studies, one reported one of 37 participants using reactive gel surfaces developed new pressure ulcers whilst none of the participants developed new ulcers when using undefined surfaces; another study reported none of 25 participants in each study arm developed new ulcers.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias, and twice for imprecision)	It is uncertain if there is a difference between reactive gel surfaces and undefined reactive surfaces in the proportion of participants developing a new pressure ulcer.
Reactive sheepskin surfaces versus undefined 'standard hospital surfaces' (Shi 2021d; three RCTs with 1424 participants)	Acute and long‐term care settings	Three studies (1424 participants) all suggested that reactive sheepskin surfaces were associated with lower proportions of participants developing a new pressure ulcer than 'standard hospital surfaces'.	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded twice for risk of bias)	Reactive sheepskin surfaces may reduce the proportion of participants developing a new pressure ulcer compared with standard hospital surfaces.
Reactive gel surfaces versus reactive gel surfaces (Shi 2021d; one study, 113 participants)	Operating room	One study reported this outcome but indicated no pressure ulcers developed.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and twice for imprecision)	It is uncertain if there is a difference in the proportion of participants developing a new pressure ulcer between these two types of use of reactive gel surfaces.
Reactive water surfaces versus reactive fibre surfaces (Shi 2021d; one study, 87 participants)	Acute care setting	One study reported no outcomes directly relevant to this review and so none of its data were analysable.	Not applicable	Not applicable	Not applicable	Not applicable	Not applicable
Time to pressure ulcer incidence
Alternating pressure (active) air surfaces versus foam surfaces (Shi 2021a; Shi 2021b; 2 RCTs with 2105 participants)	Acute and long‐term care setting	HR 0.41, 0.10 to 1.64	98 per 1000	41 per 1000 (10 to 156)	57 fewer per 1000 (88 fewer to 58 more)	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, once for moderate imprecision, and twice for substantial inconsistency)	It is uncertain if there is a difference between alternating pressure (active) air surfaces and foam surfaces in the hazard of developing new pressure ulcers.
Alternating pressure (active) air surfaces versus reactive air surfaces (Shi 2021a; Shi 2021c; 1 RCT with 308 participants)	Long‐term care setting	HR 2.25, 1.05 to 4.83	52 per 1000	113 per 1000 (54 to 227)	61 more per 1000 (2 more to 175 more)	⊕⊕⊝⊝ LOW (downgraded twice for high risk of detection bias)	People treated with alternating pressure (active) air surfaces may have a higher risk of developing an incident pressure ulcer than those treated with reactive air surfaces over 14 days' follow‐up at nursing home.
Alternating pressure (active) air surfaces versus another type alternating pressure (active) air surfaces (Shi 2021a; two studies with 2581 participants)	Acute and long‐term care setting	Both of the two included studies suggested no clear difference in the risk of developing an incident pressure ulcer at time up to 60 days' follow‐up between these support surfaces.	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for imprecision)	There may be little to no difference in the risk of developing an incident pressure ulcer over 60 days' follow‐up between these support surfaces.
Foam surfaces versus other types of foam surfaces (Shi 2021b; two RCTs with 146 participants)	Acute care and long‐term care setting	One study reported an unadjusted HR of 0.33 (95% CI 0.17 to 0.64) for the comparison of the viscoelastic foam surfaces with a density of 40 to 60 kg/m3 versus foam surfaces with a density of 33 kg/m3 in intensive care unit setting whilst another study reported an adjusted HR of 0.40 (95% CI 0.20 to 0.80) for the comparison of solid foam surfaces versus convoluted foam surfaces at acute care and long‐term care settings.	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for imprecision)	Viscoelastic foam surfaces with a density of 40 to 60 kg/m3 and solid foam surfaces may decrease the risk of developing incident pressure ulcers at any point in time up to one month compared with the control foam surfaces.
Foam surfaces compared with undefined standard hospital surfaces (Shi 2021b; three studies with 3072 participants)	Acute care setting	One study (1729 participants) suggested foam surfaces reduced the hazard of developing a new ulcer, whilst another two studies (1343 participants) suggested no difference between foam surfaces and 'standard hospital surfaces'.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias and twice for inconsistency)	It is uncertain whether there is a difference in the time to pressure ulcer incidence between foam surfaces and undefined standard hospital surfaces.
Reactive air surfaces versus another type of reactive air surfaces (Shi 2021c; one RCT with 123 participants)	Acute care setting	The study reported no statistically significant difference in survival analysis between the two types of reactive air surfaces (EHOB versus KinAir).	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias and twice for imprecision)	It is uncertain if there is a difference between EHOB reactive air surfaces and KinAir reactive air surfaces in reducing the number of incident pressure ulcers.
Reactive sheepskin surfaces versus undefined 'standard hospital surfaces' (Shi 2021d; three RCTs with 1424 participants)	Acute and long‐term care settings	Three studies (1424 participants) all suggested that the use of reactive sheepskin surfaces was associated with a lower hazard of having new ulcers than using standard hospital surfaces at any particular time up to six months.	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded twice for high risk of bias)	Reactive sheepskin surfaces may decrease the hazard of having new ulcers at any particular time up to six months compared with standard hospital surfaces.
Support surface‐associated patient comfort
Alternating pressure (active) air surfaces versus foam surfaces (Shi 2021a; Shi 2021b; one RCT with 76 participants)	Long‐term care setting	One study reported no significant difference in the overall satisfaction between study groups (P = 0.21).	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for high risk of bias and once for imprecision)	It is uncertain whether there is any difference in support surface‐associated patient comfort between alternating pressure (active) air surfaces and foam surfaces.
Alternating pressure (active) air surfaces versus reactive air surfaces (Shi 2021a; Shi 2021c; 4 RCTs with 1364 participants)	Acute and long‐term care setting	Three studies appeared to report equivalent comfort between their study arms whilst a fourth study seemed to suggest that the use of alternating pressure (active) air surfaces was associated with better comfort than reactive air surfaces.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias and twice for substantial inconsistency)	It is uncertain if there is any difference in support surface‐associated patient comfort between alternating pressure (active) air surfaces and reactive air surfaces.
Alternating pressure (active) air surfaces versus reactive fibre surfaces (Shi 2021a; Shi 2021d; one RCT with 187 participants)	Acute care setting	19 dropouts among 93 people using alternating pressure (active) air surfaces; and 17 of 94 using reactive fibre surfaces due to the reason of discomfort.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, once for imprecision, and once for indirectness)	It is uncertain if there is any difference in support surface‐associated patient comfort between alternating pressure (active) air surfaces and reactive fibre surfaces.
Alternating pressure (active) air surfaces versus another type alternating pressure (active) air surfaces (Shi 2021a; seven studies with 2705 participants)	Acute and long‐term care setting	The studies report a range of different measures and outcome data cannot be easily interpreted.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, once for imprecision, and once for publication bias)	It is uncertain if there is a difference in support surface‐associated patient comfort between different types of alternating pressure (active) air surfaces.
Foam surfaces versus reactive air surfaces (Shi 2021b; Shi 2021c; one RCT with 72 participants)	Acute care setting	More people using reactive air surfaces had increased comfort than those using foam surfaces on top of an alternating pressure (active) air surface; fewer people had decreased comfort (P = 0.04).	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded once for risk of bias, and once for imprecision)	It is unclear if there is a difference in patient comfort responses between reactive air surfaces and foam surfaces on top of an alternating pressure (active) air surface.
Foam surfaces versus other types of foam surfaces (Shi 2021b; four studies with 669 participants)	Acute care settings	The studies report a range of different measures and outcome data cannot be easily interpreted.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias, twice for heterogeneity and once for imprecision)	It is uncertain if there is a difference in positive patient comfort responses between different types of foam surfaces.
Foam surfaces versus undefined standard hospital surfaces (Shi 2021b; two RCTs with 1269 participants)	Acute care setting	One study measured comfort using a 5‐point scale (higher score = better comfort) and reported a mean comfort rating of 4.2 for foam surfaces and 4.0 for standard hospital mattress. Another study measured comfort using a 10‐point scale (higher score = poorer comfort) but reported no significant differences in comfort between foam mattresses (mean 2.33 and SD 0.98) and standard hospital mattress (mean 2.46 and SD 1.0).	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and once for heterogeneity)	It is uncertain if there is a difference in support surface‐associated patient comfort between foam surfaces and undefined standard hospital surfaces.
Reactive air surfaces versus undefined surfaces (alternating pressure (active) air surfaces or RIK microfluid static overlay) (Shi 2021c; one RCT with 110 participants)	Acute care setting	68 participants rated comfort: 27 of 30 participants using undefined reactive surfaces and 29 of 34 using reactive air surfaces had comfort responses.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and once for imprecision)	It is uncertain if there is a difference in support surface‐associated patient comfort between reactive air surfaces and undefined reactive surfaces.
Reactive air surfaces versus another type of reactive air surface (Shi 2021c; one RCT with 84 participants)	Acute care setting	None of 84 participants gave a 'very uncomfortable' response in either reactive air surfaces; 5 gave an 'uncomfortable' response (all using Roho); 8 gave an 'adequate' response (4 in each group), 48 gave a 'comfortable' response (24 in each group), and 23 responded 'very comfortable' (13 using Sofflex and 10 using Roho).	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for imprecision)	It is unclear if there is a difference in the support surface‐associated patient comfort between the two specific reactive air surfaces under evaluation.
Reactive gel surfaces compared with undefined surfaces (Aiartex; Shi 2021d; one RCT with 50 participants)	Long‐term care setting	20 people using undefined reactive surfaces responded with 'good' and 5 with 'excellent'; and 24 people using reactive gel surfaces responded with 'good' and 1 with 'excellent'.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and once for imprecision)	It is uncertain if there is a difference between reactive gel surfaces and undefined reactive surfaces in support surface‐associated patient comfort.
Reactive sheepskin surfaces versus undefined 'standard hospital surfaces' (Shi 2021d; one RCT with 297 participants)	Acute care setting	The study reported that people using reactive sheepskin surfaces rated comfort significantly higher than those using standard hospital surfaces (Z value of the Mann‐Whitney U test = ‐7.74, P < 0.001).	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and once for imprecision)	It is uncertain if there is a difference between reactive sheepskin surfaces and standard hospital surfaces in support surface‐associated patient comfort.
All reported adverse events
Alternating pressure (active) air surfaces versus foam surfaces (Shi 2021a; Shi 2021b; three RCTs with 2181 participants)	Acute and long‐term care setting	Two studies reported similar rates of adverse events between their study arms; and a third study reported one death but did not specify which study group the death was associated with.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias and twice for substantial inconsistency).	Available evidence was from 3 RCTs (2181 participants) that reported a variety of adverse events but data were not pooled. It is uncertain if there is any difference in reported adverse events between alternating pressure (active) air surfaces and foam surfaces.
Alternating pressure (active) air surfaces on operating tables and subsequently on ward beds versus reactive gel surfaces used in operating room followed by foam surfaces used on ward bed (Shi 2021a; Shi 2021d; one RCT with 198 participants)	Operating room	Approximately one half of people in each group reported adverse events. No difference in adverse events between groups was reported. No adverse events were related to the mattresses assigned.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias and twice for imprecision).	It is uncertain if there is any difference in all reported adverse events between alternating pressure (active) air surfaces applied on both operating tables and hospital beds and reactive gel surfaces used on operating tables followed by foam surfaces applied on hospital beds.
Alternating pressure (active) air surfaces versus another type of alternating pressure (active) air surface (Shi 2021a; one RCT with 1971 participants)	Acute and long‐term care settings	The study reported that 377 adverse events were observed among 308 participants within 60 days. However, the study authors did not report these data by study groups.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and twice for imprecision).	It is uncertain if there is a difference in the adverse effects between the two formats of alternating pressure (active) air surfaces.
Foam surfaces versus reactive air surfaces (Shi 2021b; Shi 2021c; one study with 72 participants)	Acute care setting	One study reported counts of adverse events for each group and these data could not be pooled.	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for imprecision)	It is unclear if there is a difference in adverse event rates between foam surfaces and reactive air surfaces.
Foam surfaces versus undefined surfaces (Bedcare; Shi 2021b; one RCT with 206 participants)	Long‐term care setting	One study reported this outcome and stated no reported adverse events in either study group.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded twice for risk of bias and once for imprecision).	It is uncertain if there is a difference in the adverse effects between foam surfaces and the undefined reactive surfaces.
Reactive gel surfaces compared with undefined surfaces (Aiartex; Shi 2021d; one RCT with 50 participants)	Long‐term care setting	One study reported this outcome but indicated no adverse events.	No pooling	No pooling	No pooling	⊕⊝⊝⊝ VERY LOW (downgraded once for risk of bias and twice for imprecision).	It is uncertain if there is a difference in the adverse effects between reactive gel surfaces and the undefined surfaces (Aiartex).
Health‐related quality of life
Alternating pressure (active) air surfaces versus foam surfaces (Shi 2021a; Shi 2021b; one RCT with 2029 participants; the EQ‐5D‐5L measured 267 participants; and PU‐QoL‐UI measured 233 participants)	Acute and long‐term care setting	MD in the 90‐day EQ‐5D‐5L of 0.00 (95% CI ‐0.05 to 0.05); and MD in 90‐day PU‐QoL‐UI of 0.00 (95% CI ‐0.03 to 0.03)	The mean health‐related quality of life (90‐day EQ‐5D‐5L) was 0.52 The mean health‐related quality of life (90‐day PU‐QoL‐UI) was 0.60	‐	MD 0.00 (0.05 lower to 0.05 higher) MD 0.00 (0.03 lower to 0.03 higher)	⊕⊕⊝⊝ LOW (downgraded twice for substantial imprecision)	It is unclear if there is a difference in health‐related quality of life measured using EQ‐5D‐5L or PU‐QoL‐UI at 90‐day follow‐up between alternating pressure (active) air surfaces and foam surfaces.
Reactive sheepskin surfaces versus undefined 'standard hospital surfaces' (Shi 2021d; one RCT with 588 participants; outcome measured on a 100‐point visual analogue scale, higher = better)	Long‐term care setting	The quality of life for those with ulcers using reactive sheepskin surfaces had a mean of 62.1 on a 100‐point visual analogue scale (higher = better) compared with 61.3 for those using standard hospital surfaces (Student’s t test P = 0.71).	No pooling	No pooling	No pooling	⊕⊕⊝⊝ LOW (downgraded twice for risk of bias)	There may be little to no difference between reactive sheepskin surfaces and standard hospital surfaces in the health‐related quality of life.
Cost‐effectiveness
Alternating pressure (active) air surfaces versus foam surfaces (Shi 2021a; Shi 2021b; one RCT with 2029 participants)	Acute and long‐term care setting	Incremental cost‐effectiveness ratio (ICER) = GBP –101,699 and Net Monetary Benefit (NMB) = GBP –2114 in the probabilistic analysis, meaning alternating pressure (active) air surfaces have lower costs and higher QALY (quality‐adjusted life‐years) values. Alternating pressure (active) air surfaces had a 99% probability of being cost‐effective at a threshold of GBP 20,000 and alternating pressure (active) air surfaces dominated reactive foam surfaces.	Not applicable	Not applicable	Not applicable	⊕⊕⊕⊝ MODERATE (downgraded once for imprecision).	Alternating pressure (active) air surfaces probably dominate reactive foam surfaces, meaning they are the cost‐effective option.
Alternating pressure (active) air surfaces versus another type of alternating pressure (active) air surface (Shi 2021a; one RCT with 1971 participants)	Acute and long‐term care settings	The cost effectiveness acceptability curve indicated that, on average, alternating pressure mattresses were associated with an 80% probability of being cost‐saving compared with alternating pressure overlays.	Not applicable	Not applicable	Not applicable	⊕⊕⊕⊝ MODERATE (downgraded once for risk of bias)	Alternating pressure air mattresses are probably more cost‐effective than alternating pressure air overlays.
Foam surfaces versus standard hospital surfaces (Shi 2021b; one RCT with 1168 participants)	Acute care setting	Foam surfaces have an 88% probability of being cost‐effective compared with standard hospital surfaces in preventing any pressure ulcer (including blanching erythema); and have a 95% probability of being cost‐effective in preventing non‐blanching erythema or worse.	Not applicable	Not applicable	Not applicable	⊕⊕⊝⊝ LOW (downgraded twice for risk of bias)	Foam surfaces may be more cost‐effective than standard hospital surfaces in preventing pressure ulceration.
Reactive air surfaces versus standard hospital surfaces (Shi 2021c; one RCT with 100 participants)	Acute care setting	One study, that did not express the outcome as the incremental cost per health benefit gained, reported that, when reactive air surfaces were used, the cost saved per 100 participants at risk was Canadian dollars 6302.6; pressure ulcers prevented per 100 participants at risk were 64; and therefore, reactive air surfaces dominated standard hospital surfaces.	Not applicable	Not applicable	Not applicable	⊕⊕⊝⊝ LOW (downgraded once for risk of bias and once for indirectness)	Reactive air surfaces are more cost‐effective than standard hospital surfaces.