ABSTRACT: BACKGROUND:Changes in well-being of patients with multiple myeloma (MM) before and after diagnosis have not been quantified. AIMS:Explore the use of secondary data to examine the changes in the well-being of older patients with MM. METHODS:We used the Health and Retirement Study (HRS), linked to Medicare claims to identify older MM patients. We compared patient-reported measures (PRM), including physical impairment, sensory impairment, and patient experience (significant pain, self-rated health, depression) in the interviews before and after MM diagnosis using McNemar's test. We propensity-matched each MM patient to five HRS participants without MM diagnosis based on baseline characteristics. We compared the change in PRM between the MM patients and their matches. RESULTS:We identified 92 HRS patients with MM diagnosis (mean age?=?74.6, SD?=?8.4). Among the surviving patients, there was a decline in well-being across most measures, including ADL difficulty (23% to 40%, p value?=?0.016), poor or fair self-rated health (38% to 61%, p value?=?0.004), and depression (15% to 30%, p value?=?0.021). Surviving patients reported worse health than participants without MM across most measures, including ADL difficulty (40% vs. 27%, p value?=?0.04), significant pain (38% vs. 22%, p value?=?0.01), and depression (29% vs. 11%, p value?=?0.003). DISCUSSION:Secondary data were used to identify patients with MM diagnosis, and examine changes across multiple measures of well-being. MM diagnosis negatively affects several aspects of patients' well-being, and these declines are larger than those experienced by similar participants without MM. CONCLUSION:The results of this study are valuable addition to understanding the experience of patients with MM, despite several data limitations.