Use of administrative data or clinical databases as predictors of risk of death in hospital: comparison of models.
OBJECTIVE
To compare risk prediction models for death in hospital based on an administrative database with published results based on data derived from three national clinical databases: the national cardiac surgical database, the national vascular database and the colorectal cancer study.


METHODS
Analysis of inpatient hospital episode statistics. Predictive model developed using multiple logistic regression.


METHODS
NHS hospital trusts in England.


METHODS
All patients admitted to an NHS hospital within England for isolated coronary artery bypass graft (CABG), repair of abdominal aortic aneurysm, and colorectal excision for cancer from 1996-7 to 2003-4.


METHODS
Deaths in hospital. Performance of models assessed with receiver operating characteristic (ROC) curve scores measuring discrimination (<0.7=poor, 0.7-0.8=reasonable, >0.8=good) and both Hosmer-Lemeshow statistics and standardised residuals measuring goodness of fit.


RESULTS
During the study period 152 523 cases of isolated CABG with 3247 deaths in hospital (2.1%), 12 781 repairs of ruptured abdominal aortic aneurysm (5987 deaths, 46.8%), 31 705 repairs of unruptured abdominal aortic aneurysm (3246 deaths, 10.2%), and 144,370 colorectal resections for cancer (10,424 deaths, 7.2%) were recorded. The power of the complex predictive model was comparable with that of models based on clinical datasets with ROC curve scores of 0.77 (v 0.78 from clinical database) for isolated CABG, 0.66 (v 0.65) and 0.74 (v 0.70) for repairs of ruptured and unruptured abdominal aortic aneurysm, respectively, and 0.80 (v 0.78) for colorectal excision for cancer. Calibration plots generally showed good agreement between observed and predicted mortality.


CONCLUSIONS
Routinely collected administrative data can be used to predict risk with similar discrimination to clinical databases. The creative use of such data to adjust for case mix would be useful for monitoring healthcare performance and could usefully complement clinical databases. Further work on other procedures and diagnoses could result in a suite of models for performance adjusted for case mix for a range of specialties and procedures.
Aylin
Paul
P
Dr Foster Unit, Imperial College London, London EC1A 9LA. p.aylin@imperial.ac.uk
Bottle
Alex
A
Majeed
Azeem
A
D000328:Adult; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality; D001019:Aortic Rupture / Q000401:mortality; D015179:Colorectal Neoplasms / Q000401:mortality; D003625:Data Collection / Q000592:standards; D019992:Databases as Topic / Q000706:statistics & numerical data*; D004739:England; D006298:Health Services Administration / Q000706:statistics & numerical data*; D017052:Hospital Mortality; D006801:Humans; D008875:Middle Aged; D015233:Models, Statistical; D016017:Odds Ratio; D011364:Professional Practice / Q000592:standards; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013222:State Medicine / Q000706:statistics & numerical data