Berthe 2007.

Study characteristics
Methods	Study objective: to determine the effectiveness in pressure‐sore prevention of an interface pressure‐decreasing mattress, the Kliniplot® mattress Study design: randomised controlled trial Study grouping: parallel group Duration of follow‐up: 7 months Number of arms: 2 Single centre or multi‐sites: single centre Study start date and end date: not described; recruited between October 1997 and April 1998 Setting: hospital
Participants	Baseline characteristics Inclusion criteria: patients free of bed‐sores admitted for at least 24 hours to 3 medical and 3 surgical departments Exclusion criteria: patients with disc hernias in the department of neurosurgery; and those with pressure sores Sex (M:F): not given Age (years): not given Baseline skin status: overall mean modified Ek’s scale score 3.56 (SD 0.84) estimated by the review authors using the reported raw data; without existing ulcers Group difference: no difference in baseline pressure ulcer risk Total number of participants: n = 1729 Unit of analysis: individuals Unit of randomisation (per patient): individuals
Interventions	Intervention characteristics Kliniplot® mattress Description of interventions: mattress with a foamy‐block structure. The mossy blocks were designed to decrease the localised high interface pressure points, by redistributing the pressure along the entire surface of the patient. NPIAP S3I classification: non‐powered, reactive foam surface; the foam characteristics unspecified Co‐interventions: not described Number of participants randomised: not described Number of participants analysed: n = 657 Standard hospital mattress Description of interventions: standard mattress NPIAP S3I classification: standard hospital surface Co‐interventions: not described Number of participants randomised: not described Number of participants analysed: n = 1072
Outcomes	Proportion of participants developing a new pressure ulcer Outcome type: binary Time points: 7 months Reporting: partially reported Measurement method (e.g. scale, self‐reporting): graded the severity of pressure sores by using the modified Shea’s pressure sore grading Definition (including ulcer stage): incidence of ulcers at any stage Dropouts: not described Notes (e.g. other results reported): 21 of 657 patients (3.2%) on Kliniplot® mattress, and 21 of 1072 patients (1.9%) on standard mattress developed bed‐sores (P = 0.154) Time to pressure ulcer incidence Outcome type: time‐to‐event (but not survival analysis) Time points: 7 months Reporting: fully reported Measurement method (e.g. scale, self‐reporting): see above Definition (including ulcer stage): median time to pressure ulcer incidence Dropouts: not given Notes: median time to pressure ulcer incidence 31 days (range 6 to 87) for Kliniplot® mattress and 18 days (range 2 to 38) for standard mattress (P < 0.001). HR 0.35 (95% CI 0.19 to 0.66) estimated by the review authors by using methods described in Tierney 2007. Support‐surface‐associated patient comfort Not reported All reported adverse events using allocated support surfaces Not reported Health‐related quality of life (HRQOL) Not reported Cost‐effectiveness Not reported Outcomes that are not considered in this review but reported in trials: None
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "... were freely assigned to a bed which has been randomly equipped in advance either with a Kliniplot® mattress, or with a standard mattress" Comment: unclear risk of bias because the sequence generation method is not specified.
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	Comment: no information provided.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: no information provided.
Selective reporting (reporting bias)	Low risk	Comment: the study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre‐specified.
Other bias	Low risk	Comment: the study appears to be free of other sources of bias.