Hospital-acquired pressure ulcers: risk factors and use of preventive devices.

BACKGROUND Pressure ulcers are a frequent complication of bed rest. We examined risk factors for hospital-acquired pressure ulcers, the use of preventive devices, and the impact of case-mix adjustments on between-ward comparisons. METHODS We conducted 3 cross-sectional surveys in a teaching hospital of 2373 patients who had no pressure ulcer on admission. We assessed the presence of pressure ulcer, dates of admission and ulcer occurrence, hospital ward, patient age and sex, appetite and route of nutrition, surgery during stay, hospitalization for fracture, comorbidities, use of low-pressure devices (special mattresses, cushions, and pressure-reducing beds), and the Norton Pressure Ulcer Prediction score (physical condition, mental condition, activity, mobility, and incontinence). RESULTS Two hundred forty-seven new pressure ulcers occurred (5.7 per 1000 person-days). In multivariate analysis, the risk for pressure ulcer increased with age (risk gradient across 5 categories was 1:4.5; P<.001) and Norton score (across 5 categories, risk gradient was 30-fold; P<.001); other risk factors (all relative risks, 1.5-1.8; P<.002) were hospitalization for fracture, surgical intervention, reduced appetite, and nasogastric tube or intravenous nutrition. Adjustment for case mix substantially modified differences between hospital wards. Use of preventive devices was associated with Norton score, but not all high-risk patients benefited. CONCLUSIONS Pressure ulcers were seen in every 10th hospitalized adult. Patient age and Norton score were the strongest risk factors for pressure ulcers. Use of preventive devices was suboptimal. Adjustment for case mix is essential if pressure ulcer incidence is to be used as an indicator of quality of care.