One hundred and twenty studies met the inclusion criteria for the review.
Effectiveness of risk assessment tools: In terms of pressure ulcer development, good quality RCTs showed no difference between clinical judgement and the Waterlow scale (RR 1.4, 95% CI 0.82 to 2.4) or the Ramstadius tool (RR 0.77, 95% CI, 0.44 to 1.4). The modified Norton scale was associated with lower risk of pressure ulcers compared with clinical judgment in one poor quality trial (RR 0.11, 95% CI, 0.03 to 0.46; one RCT) but no difference between the Braden scale and clinical judgment in a second poor quality trial. The strength of evidence was considered insufficient.
Comparison of risk assessment tools: The median AUC was 0.77 (range 0.55 to 0.88; seven studies) for the Braden scale, 0.74 (range 0.56 to 0.75; three studies) for the Norton scale, 0.61 (range 0.54 to 0.66; four studies) for the Waterlow scale and 0.83 (range 0.72 to 0.90; three studies) for the Cubbin and Jackson scale. There was no clear difference across instruments in six studies of direct comparisons. The strength of evidence was considered moderate.
Effectiveness of preventive interventions: Static mattresses and overlays were consistently found to lower the risk of developing pressure ulcers compared with standard mattresses in good and fair quality randomised trials in high risk populations (range of RR 0.16 to 0.82; five studies). Most trials (20 out of 25 comparisons) showed no differences between alternating air mattresses and low air loss mattresses and various static mattresses and overlays. The strength of evidence was considered insufficient to moderate.
Harms of preventive interventions: No studies evaluated harms directly. Reported harms were too limited for assessment.
Results for a wide range of interventions other than mattresses that were assessed in individual or poor quality studies were also reported, as were results for studies reporting differences across settings and/or patient characteristics for each review question.