Measuring Multimorbidity: A Risky Business

Excerpt

The influence of multiple coexisting conditions (multimorbidity) on patient outcomes is well established, but the optimal method for measuring multimorbidity is not. In this issue of JGIM, Radomski and colleagues present findings from a national cohort of Veterans Affairs (VA) and non-VA administrative files used to estimate and compare health outcomes for veterans over age 65 with diabetes who are using dual sources of care.1 The primary outcome was mortality, and the major finding was that mortality rates differed depending on which measure of multimorbidity was used. For example, in the model controlling for multimorbidity based on International Classification of Disease (ICD) diagnostic codes, the dual-use groups had lower odds of death than VA-predominant users. On the other hand, in the model based on pharmacy records, the dual-use groups had higher odds of death than VA-predominant users. The authors point out the importance of measuring multimorbidity and outline the need for reliable risk adjustment methods that are not susceptible to measurement differences across health systems. …