Classifying Multimorbidity Using Drug Concepts via the Rx‐Risk Comorbidity Index: Methods and Comparative Cross‐Sectional Study

The study objective was to update a method to identify comorbid conditions using only medication information in circumstances in which diagnosis codes may be undercaptured, such as in single-specialty electronic health records (EHRs), and to compare the distribution of comorbidities across Rx-Risk versus other traditional comorbidity indices.