The ICD-10 Charlson Comorbidity Index predicted mortality but not resource utilization following hip fracture

Barbara Toson1, Lara A Harvey1, Jacqueline C T Close2

  • 1Falls and Injury Prevention Group, Neuroscience Research Australia, University of New South Wales, Barker Street, Randwick, NSW 2031, Australia.

Insights

The Charlson Comorbidity Index (CCI) effectively predicts mortality in hip fracture patients but not resource utilization. Using individual conditions and the Quan algorithm is recommended for better prediction in administrative data.

Area of Science:

  • Geriatric Medicine
  • Health Services Research
  • Epidemiology

Background:

  • Hip fractures represent a significant health burden in older adults.
  • Accurate prediction of outcomes is crucial for resource allocation and patient management.
  • The Charlson Comorbidity Index (CCI) is a widely used comorbidity measure, but its performance in hip fracture populations using administrative data requires evaluation.

Purpose of the Study:

  • To assess the performance of the Charlson Comorbidity Index (CCI) in predicting mortality, 30-day readmission, and length of stay (LOS) in hip fracture patients.
  • To compare the effectiveness of different International Classification of Diseases, 10th Revision (ICD-10) coding algorithms for comorbidity assessment.
  • To determine optimal modeling strategies for predicting outcomes in this population.

Main Methods:

  • Utilized linked hospitalization and death data for 47,698 New South Wales residents aged 65+ admitted for hip fracture.
  • Ascertained comorbidities using ICD-10 coding algorithms (Sundararajan 2004, Quan 2005).
  • Employed regression models, assessing area under the receiver operating curve (AUC) and Akaike information criterion for model fit and discrimination.

Main Results:

  • Both algorithms demonstrated acceptable discrimination for in-hospital, 30-day, and 1-year mortality (AUC 0.69-0.76).
  • Predictive ability for 30-day readmission (AUC 0.54-0.57) and LOS (adjusted R(2) 0.007-0.045) was poor.
  • The Quan algorithm showed better model fit; modeling individual conditions outperformed weighted scores. A 1-year lookback improved 1-year mortality prediction.

Conclusions:

  • The CCI is a valid tool for predicting mortality in hip fracture patients but not for resource utilization (LOS, readmission).
  • The Quan algorithm is preferable to the Sundararajan algorithm for comorbidity assessment in this context.
  • Modeling individual conditions rather than using categorized weighted scores is recommended for improved predictive accuracy.
Abstract