Whittingham 1999.

Study characteristics
Methods	Study objective: not given Study design: randomised controlled trial Study grouping: parallel group Duration of follow‐up: 12 months Number of arms: 6 Single centre or multi‐sites: single centre Study start date and end date: not described Setting: elderly assessment unit
Participants	Baseline characteristics Inclusion criteria: at high risk of pressure sores (Waterlow) and dependent (Barthel); all patients admitted onto research mattresses were included, unless their skin had grade 3 (Stirling) or above pressure damage, or their skin condition deteriorated to grade 2/3 damage Exclusion criteria: not given Sex (M:F): not given Age (years): not given Baseline skin status: at high risk Group difference: not given Total number of participants: n = 309 Unit of analysis: individuals Unit of randomisation (per patient): individuals
Interventions	Intervention characteristics Improtec (Spenco International) Description of interventions: Improtec (Spenco International) NPIAP S3I classification: non‐powered, reactive foam surface; insufficient information for specifying foam quality Co‐interventions: not described Number of participants randomised: not given Number of participants analysed: not given Pentaflex (Huntleigh Healthcare) Description of interventions: Pentaflex (Huntleigh Healthcare) NPIAP S3I classification: non‐powered, reactive foam surface; insufficient information for specifying foam quality Co‐interventions: not described Number of participants randomised: not given Number of participants analysed: not given Serendipity (Talley) Description of interventions: Serendipity (Talley) NPIAP S3I classification: non‐powered, reactive foam surface; insufficient information for specifying foam quality Co‐interventions: not described Number of participants randomised: not given Number of participants analysed: not given Softform Description of interventions: Softform (Medical Support System) NPIAP S3I classification: non‐powered, reactive foam surface; high specification foam according to Gray 1994 Co‐interventions: not described Number of participants randomised: not given Number of participants analysed: not given Transwave Description of interventions: Transwave (Karomed) NPIAP S3I classification: non‐powered, reactive foam surface Co‐interventions: not described Number of participants randomised: not given Number of participants analysed: not given Vapourlux Description of interventions: Vapourlux (Parkhouse) NPIAP S3I classification: non‐powered, reactive foam surface; insufficient information for specifying foam quality Co‐interventions: not described Number of participants randomised: not given Number of participants analysed: not given
Outcomes	Proportion of participants developing a new pressure ulcer Outcome type: unclear Time points: 12 months Reporting: partially reported Measurement method (e.g. scale, self‐reporting): not given Definition (including ulcer stage): pressure sore incidence Dropouts: not described Notes (e.g. other results reported): overall pressure sore incidence 16.5% (range 7 to 16.7% according to mattress), and the majority were grade 1 to 2 (Stirling) Time to pressure ulcer incidence Not reported Support‐surface‐associated patient comfort Outcome type: unclear Time points: 12 months Reporting: partially reported Measurement method (e.g. scale, self‐reporting): not given Definition: patient comfort ratings Dropouts: not given Notes: comfort ratings were similarly good for all 6 mattresses initially. However, this altered by the end of the 12 months. All reported adverse events using allocated support surfaces Not reported Health‐related quality of life (HRQOL) Not reported Cost‐effectiveness Not reported
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: unclear risk of bias because the sequence generation process was not described.
Allocation concealment (selection bias)	Unclear risk	Comment: no information provided.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: no information provided.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Outcome group: all outcomes Quote: "Data were collected by a single researcher" Comment: unclear risk of bias because it is unclear if outcome assessment was blinded.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: no information provided.
Selective reporting (reporting bias)	Unclear risk	Comment: no information provided.
Other bias	Unclear risk	Comment: no information provided.