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Predictive validity of five comorbidity indices in prostate carcinoma patients treated with curative intent
Author(s) -
Boulos David L.,
Groome Patti A.,
Brundage Michael D.,
Siemens D. Robert,
Mackillop William J.,
Heaton Jeremy P.W.,
Schulze Karleen M.,
Rohland Susan L.
Publication year - 2006
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.21813
Subject(s) - medicine , comorbidity , prostate carcinoma , carcinoma , prostate , oncology , urology , cancer
Abstract BACKGROUND 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. METHODS 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. RESULTS 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). CONCLUSIONS 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.