A validation study of the CirCom comorbidity score in an English cirrhosis population using the Clinical Practice Research Datalink
Received 28 July 2017
Accepted for publication 20 November 2017
Published 15 January 2018 Volume 2018:10 Pages 107—120
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr Vera Ehrenstein
Colin J Crooks,1,2 Joe West,1,2 Peter Jepsen3,4
1Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK; 2Nottingham Digestive Diseases Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK; 3Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark; 4Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark
Purpose: The CirCom score has been developed from Danish data as a specific measure of comorbidity for cirrhosis to predict all-cause mortality. We compared its performance with the Charlson Comorbidity Index (CCI) in an English cirrhosis population.
Patients and methods: We used comorbidity scores in a survival model to predict mortality in a cirrhosis cohort in the Clinical Practice Research Datalink. The discrimination of each score was compared by age, gender, socioeconomic status, cirrhosis etiology, cirrhosis stage, and year after cirrhosis diagnosis. We also measured their ability to predict liver-related versus non-liver-related death.
Results: There was a small improvement in the C statistic from the model using the CirCom score (C=0.63) compared to the CCI (C=0.62), and there was an overall improvement in the net reclassification index of 1.5%. The improvement was more notable in younger patients, those with an alcohol etiology, and those with compensated cirrhosis. Both scores performed better (C statistic >0.7) for non-liver-related deaths than liver-related deaths (C statistic <0.6), as comorbidity was only weakly predictive of liver-related death.
Conclusion: The CirCom score provided a small improvement in performance over the CCI in the prediction of all-cause and non-liver mortality, but not liver-related mortality. Therefore, it is important to include a measure of comorbidity in studies of cirrhosis survival, alongside a measure of cirrhosis severity.
Keywords: cirrhosis, mortality, comorbidity, prognosis, cause of death, cohort
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