Charlson scores based on ICD-10 administrative data were valid in assessing comorbidity in patients undergoing urological cancer surgery.
OBJECTIVE
Adjustment for comorbidity is an essential component of any observational study comparing outcomes. We evaluated the validity of the Charlson comorbidity score based on ICD-10 codes in patients undergoing urological cancer surgery within an English administrative database.


METHODS
Patients who underwent radical urological cancer surgery between 1998 and 2002 in the English National Health Service were identified from the Hospital Episode Statistics database (N = 20,138). ICD-9-CM codes defining comorbid diseases according to the Deyo and Dartmouth-Manitoba adaptations of the Charlson comorbidity score were translated into ICD-10 codes.


RESULTS
Charlson scores derived by the ICD-10 translation of the Deyo and Dartmouth-Manitoba adaptations were identical in 16,623 patients (83%; kappa = .63). For both adaptations, ICD-10 scores increased with age, were higher in patients admitted on an emergency basis, and predicted short-term outcome. Addition of either the ICD-10 Charlson Deyo or Dartmouth-Manitoba score to risk models containing age and sex to predict in-hospital mortality resulted in a better model fit but only in small improvements of the predictive power.


CONCLUSIONS
The ICD-10 translations of the Deyo and Dartmouth-Manitoba adaptations performed similarly in risk models predicting hospital mortality following urological cancer surgery. Adjustment for comorbidity over and above age and sex alone does not seem to provide a large improvement.
Nuttall
Martin
M
Clinical Effectiveness Unit, The Royal College of Surgeons of England, 35-43 Lincoln's Inn Fields, London WC2A 3PE, United Kingdom.
van der Meulen
Jan
J
Emberton
Mark
M
D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D015986:Confounding Factors, Epidemiologic; D005260:Female; D005568:Forms and Records Control; D017052:Hospital Mortality; D006801:Humans; D038801:International Classification of Diseases; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012107:Research Design; D020379:Risk Adjustment / Q000379:methods*; D014571:Urologic Neoplasms / Q000401:mortality / Q000601:surgery*