Table 4.

 Areas under receiver operating characteristic curve (95% confidence intervals) for the Norton, Braden, and Waterlow risk assessment scales for pressure ulcers at each week of follow up of hospitalised patients

Week	No	Norton scale	Braden scale	Waterlow scale
All patients
1	1228	0.51 (0.44 to 0.58)	0.52 (0.45 to 0.59)	0.60 (0.53 to 0.66)
2	451	0.68 (0.59 to 0.77)	0.66 (0.56 to 0.76)	0.66 (0.56 to 0.76)
3	196	0.64 (0.50 to 0.79)	0.74 (0.59 to 0.88)	0.73 (0.60 to 0.86)
4	111	0.72 (0.52 to 0.92)	0.68 (0.48 to 0.88)	0.61 (0.46 to 0.76)
Subpopulation*
1	460	0.69 (0.63 to 0.76)	0.70 (0.63 to 0.77)	0.67 (0.61 to 0.73)
2	390	0.71 (0.61 to 0.81)	0.70 (0.60 to 0.81)	0.65 (0.55 to 0.75)
3	169	0.65 (0.49 to 0.82)	0.69 (0.51 to 0.87)	0.73 (0.60 to 0.87)
4	110	0.82 (0.67 to 0.97)	0.76 (0.57 to 0.95)	0.67 (0.54 to 0.80)

^*Excluding patients given preventive measures who did not develop pressure ulcers (n=57) and surgical patients (n=747).