Calibration power of the Braden scale in predicting pressure ulcer development.
OBJECTIVE
Calibration is the degree of correspondence between the estimated probability produced by a model and the actual observed probability. The aim of this study was to investigate the calibration power of the Braden scale in predicting pressure ulcer development (PU).


METHODS
A retrospective analysis was performed among consecutive patients in 2013. The patients were separated into training a group and a validation group. The predicted incidence was calculated using a logistic regression model in the training group and the Hosmer-Lemeshow test was used for assessing the goodness of fit. In the validation cohort, the observed and the predicted incidence were compared by the Chi-square (χ2) goodness of fit test for calibration power.


RESULTS
We included 2585 patients in the study, of these 78 patients (3.0%) developed a PU. Between the training and validation groups the patient characteristics were non-significant (p>0.05). In the training group, the logistic regression model for predicting pressure ulcer was Logit(P) = -0.433*Braden score+2.616. The Hosmer-Lemeshow test showed no goodness fit (χ2=13.472; p=0.019). In the validation group, the predicted pressure ulcer incidence also did not fit well with the observed incidence (χ2=42.154, p=0.000 by Braden scores; and χ2=17.223, p=0.001 by Braden scale risk classification).


CONCLUSIONS
The Braden scale has low calibration power in predicting PU formation.
Associate Professor, School of Nursing, Nantong University, Nantong city, Jiangsu province, P.R.China.
Hong-Lin
HL
Chen
Qilu Hospital of Shandong University, Jinan city, Shandong province, P.R.China.
Ying-Juan
YJ
Cao
Department of Cardiosurgery, Qilu Hospital of Shandong University, Jinan city, Shandong province, P.R.China.
Jing
J
Wang
Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan city, Shandong province, P.R.China.
Bao-Sha
BS
Huai
D000328:Adult; D000368:Aged; D002138:Calibration; D005260:Female; D005544:Forecasting; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D003668:Pressure Ulcer / Q000145:classification* / Q000503:physiopathology*; D012189:Retrospective Studies; D012307:Risk Factors; D015599:Trauma Severity Indices; D014945:Wound Healing / Q000502:physiology*
Braden scale; calibration power; pressure ulcer