title: Weighted versus unweighted Charlson score to predict long-term other-cause mortality in men with early-stage prostate cancer.
abstract: BACKGROUND
  Clinicians need a simple yet accurate method to predict other-cause mortality to inform medical decision making for men with prostate cancer (PCa).
  
  
  OBJECTIVE
  To compare weighted and unweighted Charlson Comorbidity Index scores in predicting long-term, other-cause mortality in men with early-stage PCa.
  
  
  METHODS
  A retrospective cohort study of 1482 men with early-stage PCa diagnosed in 1998-2004 at two Southern California Veterans Affairs medical centers.
  
  
  METHODS
  Subhazard ratios and cumulative incidence of other-cause mortality associated with weighted and unweighted Charlson scores, calculated by competing-risks regression accounting for cancer mortality, along with Harrell concordance index (C-index) values.
  
  
  CONCLUSIONS
  Weighted and unweighted Charlson scores were identical in 88.6% of subjects (1313 of 1482 men) across all scores and in 91.7% of subjects (1359 of 1482 men) across scores of 0, 1, 2, and ≥3. In competing-risks analysis, hazards of other-cause mortality were similar when comparing weighted and unweighted scores. Men with weighted scores of 1, 2, and ≥3 (vs. 0) had subhazard ratios of 2.3 (95% confidence interval [CI], 1.6-3.2), 4.1 (95% CI, 2.9-5.8), and 8.3 (95% CI, 5.9-11.5), respectively. Men with unweighted scores of 1, 2, and ≥3 (vs. 0) had subhazard ratios of 2.5 (95% CI, 1.8-3.5), 4.5 (95% CI, 3.2-6.3), and 10.3 (95% CI, 7.2-14.7), respectively. The C-indexes for prediction of other-cause mortality were nearly identical for weighted scores (0.759 [95% CI, 0.715-0.780]) and unweighted scores (0.756 [95% CI, 0.717-0.780]). The difference in C-index between the two methods was -0.003 (95% CI, -0.01 to 0.004).
  
  
  CONCLUSIONS
  An unweighted Charlson score yields similar strength of association and variance in predicting long-term, other-cause mortality compared with a weighted Charlson score.
  
  
  RESULTS
  A simple count of major comorbidities provides similar accuracy to a weighted index in predicting death from other causes in men with early-stage prostate cancer.
authors.affiliation: Department of Urology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Greater Los Angeles Veterans Affairs Medical Center, Los Angeles, CA, USA. Electronic address: Tdaskivich@ucla.edu.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Daskivich
authors.affiliation: Department of Urology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
authors.forename: Lorna
authors.initials: L
authors.lastname: Kwan
authors.affiliation: Department of Urology, University of Washington, Seattle, WA, USA.
authors.forename: Atreya
authors.initials: A
authors.lastname: Dash
authors.affiliation: Center for Health Policy Research and Department of Medicine, University of California, Irvine, Irvine, CA, USA.
authors.forename: Sheldon
authors.initials: S
authors.lastname: Greenfield
authors.affiliation: Department of Urology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA, USA; Department of Health Policy and Management, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, USA.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Litwin
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D000368:Aged; D002140:California / Q000453:epidemiology; D002423:Cause of Death; D015897:Comorbidity; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011471:Prostatic Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D012189:Retrospective Studies; D013997:Time Factors
keywords: Comorbidity; Outcome assessment; Prostate; Prostatic neoplasms; Survival