Randomized clinical trial comparing 2 support surfaces: results of the Prevention of Pressure Ulcers Study.

Objective: To determine whether a viscoelastic polymer (energy absorbing) foam mattress was superior to a standard hospital mattress for pressure ulcer prevention and to analyze the cost-effectiveness in comparison with standard hospital mattresses.

Design: Unblinded, randomized, prospective trial.

Setting: Elderly acute care, rehabilitation, and orthopedic wards at 3 hospitals in the United Kingdom.

Participants: 1168 patients at risk of developing pressure ulcers (Waterlow score, 15 to 20), with a median age of 83 years (25th to 75th percentile range, 79-87).

Interventions: Participants were allocated to either the experimental equipment (CONFOR-Med mattress/cushion combination) or a standard mattress/cushion combination; all were given standard nursing care. Pressure areas were observed daily.

Main Outcome Measure: Development of nonblanching erythema.

Results: A significant decrease in the incidence of blanching erythema (26.3% to 19.9%; P =.004) and a nonsignificant decrease in the incidence of nonblanching erythema occurred in participants allocated to the experimental equipment. However, when the survival curve plots were analyzed at 7 days, both categories showed statistically significant decreases (P =.0015 and P =.042, respectively). Participants on standard equipment had a relative odds ratio of 1.36 (95% confidence interval [CI], 1.10-1.69) for developing blanching erythema or worse and 1.46 (95% CI, 0.90-1.82) for developing nonblanching erythema or worse. To prevent nonblanching erythema, the number needed to treat (NNT) was 41.9 (95% CI, -82.6-15.3). To prevent any erythema (blanching or nonblanching), the NNT was 11.5 (95% CI, 41.6-9.3). Participants with blanching or nonblanching erythema were significantly less mobile than participants with normal skin and more likely to have worsening mobility (P <.001). For participants with similar pressure ulcer status, mattress type was not associated with difference in mobility.

Conclusions: Regardless of prevention routine, pressure ulcers occur. In this study, the experimental equipment showed statistical significance to standard equipment for prevention of blanching erythema; significance was not achieved for nonblanching erythema. Trend and survival analysis show that a larger study is required to determine whether this nonsignificant difference is genuine.