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Predictive validity of five comorbidity indices in prostate carcinoma patients treated with curative intent
Article first published online: 13 MAR 2006
Copyright © 2006 American Cancer Society
Volume 106, Issue 8, pages 1804–1814, 15 April 2006
How to Cite
Boulos, D. L., Groome, P. A., Brundage, M. D., Siemens, D. R., Mackillop, W. J., Heaton, J. P.W., Schulze, K. M. and Rohland, S. L. (2006), Predictive validity of five comorbidity indices in prostate carcinoma patients treated with curative intent. Cancer, 106: 1804–1814. doi: 10.1002/cncr.21813
- Issue published online: 4 APR 2006
- Article first published online: 13 MAR 2006
- Manuscript Accepted: 15 NOV 2005
- Manuscript Revised: 28 SEP 2005
- Manuscript Received: 27 JUL 2005
- Canadian Cancer Society through the National Cancer Institute of Canada
- survival rate;
- health status indicators;
- predictive value of tests;
- reproducibility of results;
- prostatic neoplasms
Comorbidity is important to consider in clinical research on curative prostate carcinoma because of the role of competing risks. Five chart-based comorbidity indices were assessed for their ability to predict survival.
This was a case-cohort study of prostate carcinoma patient cohort treated with curative intent in Toronto and Southeast Cancer Care Ontario regions between 1990 and 1996; the subcohort was drawn from these men, whereas cases were cohort members who died from causes other than prostate carcinoma. Comorbidity data were obtained from medical charts (269 subjects). Vital status, age, area of residence, and socioeconomic status information were available. Predictive validity was quantified by the percent variance explained (PVE) over and above age using proportional hazards modeling.
The Chronic Disease Score (CDS) (PVE = 11.3%; 95% confidence interval [95% CI], 3.5-22.8%), Index of Coexistent Disease (ICED) (PVE = 9.0%; 95% CI, 2.9-17.9%), Cumulative Illness Rating Scale (CIRS) (PVE = 7.2%; 95% CI, 1.4-17.1%), Kaplan-Feinstein Index (PVE = 4.9%; 95% CI, 0.6-12.8%), and Charlson Index (PVE = 3.8%; 95% CI, 0.3-10.9%) each explained some outcome variability beyond age. PVE differences among indices were not statistically significant. A comorbidity identified at the time of cancer diagnosis was the cause of death in 59.2% of cases (75% for cardiac or vascular causes).
The better-performing, more comprehensive indices (CDS, ICED, and CIRS) would be useful in measuring and controlling for comorbidity in this setting. The CDS was easiest to apply and explained the most outcome variability. Cancer 2006. © 2006 American Cancer Society.