Patient and organisational variables associated with pressure ulcer prevalence in hospital settings: a multilevel analysis

Objectives: To investigate the association of ward-level differences in the odds of hospital-acquired pressure ulcers (HAPUs) with selected ward organisational variables and patient risk factors. Design: Multilevel approach to data from 2 cross-sectional studies. Settings: 4 hospitals in Norway were studied. Participants: 1056 patients at 84 somatic wards. Primary outcome measure: HAPU. Results: Significant variance in the odds of HAPUs was found across wards. A regression model using only organisational variables left a significant variance in the odds of HAPUs across wards but patient variables eliminated the across-ward variance. In the model including organisational and patient variables, significant ward-level HAPU variables were ward type (rehabilitation vs surgery/internal medicine: OR 0.17 (95% CI 0.04 to 0.66)), use of preventive measures (yes vs no: OR 2.02 (95% CI 1.12 to 3.64)) and ward patient safety culture (OR 0.97 (95% CI 0.96 to 0.99)). Significant patient-level predictors were age > 70 vs < 70 (OR 2.70 (95% CI 1.54 to 4.74)), Braden scale total score (OR 0.73 (95% CI 0.67 to 0.80)) and overweight (body mass index 25-29.99 kg/m(2)) (OR 0.32 (95% CI 0.17 to 0.62)). Conclusions: The fact that the odds of HAPU varied across wards, and that across-ward variance was reduced when the selected ward-level variables entered the explanatory model, indicates that the HAPU problem may be reduced by ward-level organisation of care improvements, that is, by improving the patient safety culture and implementation of preventive measures. Some wards may prevent pressure ulcers better than other wards. The fact that ward-level variation was eliminated when patient-level HAPU variables were included in the model indicates that even wards with the best HAPU prevention will be challenged by an influx of high-risk patients.