The extent and burden of high multimorbidity on older adults in the US: a descriptive analysis of Medicare beneficiaries.

Background: The impact of multimorbidity (≥ 2 chronic diseases) on the well-being of older adults is substantial but variable. The burden of multimorbidity varies by the number and kinds of conditions, and timing of onset. The impact varies by age, race, ethnicity, socioeconomic status, and health indicators.