Adapting the Rx-Risk-V for mortality prediction in outpatient populations

Michael L. Johnson, Hashem B. El-Serag, Tung Thomas Tran, Christine Hartman, Peter Richardson, Neena S. Abraham

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Objectives: We sought to operationalize, test, and validate an outpatient pharmacy-based case-mix adjuster. Methods: Outpatients from the Department of Veterans Affairs (VA) prescribed a nonsteroidal anti-inflammatory drug (NSAID) or cyclooxygenase-2 selective drug during 2002 were identified. We updated and extended the Rx-Risk-V by adding 26 additional disease categories and mapping them to VA drug-class codes; derived empirical weights for each from a logistic model of 1-year mortality; adjusted for age, race and sex; and scored the weights into 1 measure of comorbidity. We compared the weighted score to the Deyo diagnosis-based comorbidity index and validated it in a national cohort of 260,321 outpatients with chronic heart failure (CHF). Results: One-year mortality among the 724,270-outpatient NSAID cohort was 1.6% (n ≤ 11,766). Using a baseline model of age, race, and gender (c-index ≤ 0.716), we found that the Deyo measure improved the prediction of mortality (c-index ≤ 0.765), and the pharmacy comorbidity score further improved the prediction (c-index ≤ 0.782), an increase of 25.8%. Using both, we found further improvement (c-index ≤ 0.792). Among the CHF cohort, 9.7% (n ≤ 25,251) died within 1 year. Performance of the baseline model controlling for age, race, and gender (c index ≤ 0.620) improved with addition of the pharmacy comorbidity score (c index ≤ 0.689), compared with the addition of the Deyo measure (c index ≤ 0.651), an increase of 55.1%. Together, they slightly improved prediction in CHF patients (c index ≤ 0.695). Conclusions: The updated and extended Rx-Risk-V is useful for case-mix adjustment of mortality in an outpatient population.

Original languageEnglish (US)
Pages (from-to)793-797
Number of pages5
JournalMedical care
Volume44
Issue number8
DOIs
StatePublished - Aug 1 2006

Keywords

  • Case-mix adjustment
  • Co-morbidity in outpatients
  • Mortality prediction
  • Outcomes prediction
  • Rx-Risk-V

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

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    Johnson, M. L., El-Serag, H. B., Tran, T. T., Hartman, C., Richardson, P., & Abraham, N. S. (2006). Adapting the Rx-Risk-V for mortality prediction in outpatient populations. Medical care, 44(8), 793-797. https://doi.org/10.1097/01.mlr.0000218804.41758.ef