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The estimation power of alternative comorbidity indices
Onur Baser1, Liisa Palmer, Judith Stephenson
1STATinMED Research and University of Michigan, Ann Arbor, MI 48104, USA. obaser@statinmed.com
Summary
Comparing healthcare risk adjustment methods, combining the Charlson comorbidity index (CCI), Chronic Disease Score (CDS), and AHRQ comorbidity index (AHRQCI) offered the best statistical performance for analyzing health expenditures, though practical differences were minimal.
Area of Science:
- Health Economics
- Biostatistics
- Public Health Policy
Background:
- Healthcare expenditures are significantly impacted by the overall burden of illness.
- Accurate risk adjustment is crucial for effective health policy analysis.
- Evaluating different comorbidity indices is essential for precise expenditure estimation.
Purpose of the Study:
- To compare the estimation power of three risk adjustment methods: Charlson comorbidity index (CCI), Chronic Disease Score (CDS), and Agency for Healthcare Research and Quality's comorbidity index (AHRQCI).
- To assess the performance of these indices individually and in various combinations for analyzing healthcare expenditures.
- To determine the optimal risk adjustment strategy for health policy research.
Main Methods:
- Utilized data from the Thomson MarketScan Research Databases for migraine patients treated with triptans.
- Evaluated seven multivariate models assessing combinations of CCI, CDS, and AHRQCI.
- Assessed model fit using Bayesian and Akaike information criteria, log-likelihood scores, and pseudo R-squared values.
Main Results:
- Individual comorbidity indices yielded inconclusive results.
- The model incorporating all three indices (CCI + CDS + AHRQCI) demonstrated the strongest statistical performance.
- Practical differences in estimated healthcare expenditures between models were minor.
Conclusions:
- Low correlation among comorbidity indices suggests they capture distinct risk factors.
- No single index fully captures all potential risk factors.
- Simultaneous use of CCI, CDS, and AHRQCI in risk adjustment models is feasible and potentially beneficial due to their complementary nature.
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