Data show that nearly two-thirds of Medicare beneficiaries feel that their coverage completely meets their expectations. Despite this, a recent survey also showed that 15% of Medicare beneficiaries changed their coverage in the past two years, while another 6% had the intention of doing so, but had not yet changed their coverage.1
Most commonly, beneficiaries find themselves switching between Medicare Advantage (MA) plans, or from MA to traditional Medicare (TM), but among beneficiaries with cancer, these types of patterns of changing Medicare coverage are not as cut and dried. Even when diving into the impact of supplemental coverage (such as Medigap) on Medicare enrollment and disenrollment, it continues to be understudied among beneficiaries with cancer.
Being able to examine how the initial choice of supplemental insurance relates to plan switching is critical in order to ensure that those with high-cost health conditions have access to adequate and affordable coverage. Keeping that in mind, a cohort study published in JAMA Network Open1 sought answer the question: is the likelihood of switching Medicare plans influenced by the initial type of Medicare coverage and a history of cancer?
This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline, and did not require consent since all of the data was widely accessible.
Study design: Longitudinal analysis using health and retirement data
The researchers used Health and Retirement Study biennial data—information collected and reported every two years—from 2008-2020 to identify respondents who originally chose Medicare coverage at age 65 or 66, and completed two successive surveys: one baseline survey that gauges initial plan selection and history of cancer, and another survey that measures switching.
Being that the study mainly focused on the selection and switching of Medicare coverage, individuals who enrolled in Medicare before reaching age eligibility, those who were dually eligible for Medicaid or initially enrolled in military health plans, and those who disenrolled from Medicare after their initial plan selection (such as switching to commercial insurance) were all excluded. The main outcome being measured was self-reported switching in the two years after one’s original Medicare plan choice.
Key Takeaways
- Beneficiaries who initially chose Medicare Advantage or traditional Medicare with supplemental coverage were significantly less likely to switch plans, regardless of cancer history.
- Switching behavior was similar among beneficiaries with and without a history of cancer, challenging assumptions that serious illness prompts more frequent changes.
- Enhancing the adequacy of traditional Medicare—especially for those without supplemental coverage—may reduce the need for plan switching among high-cost, high-need populations.
Statistical methods: Adjusting for health and demographic differences
Investigators used modified Poisson regression with robust error variance to predict the probability of switching from initial Medicare coverage, adjusting for baseline sociodemographic and health-related factors and classified by cancer history. Primary estimates were unweighted, due to potential instability of survey-weighted results, although sensitivity analyses using respondent-level weights were also performed. The sample was also limited to younger retirees, excluding post-enrollment cancer diagnoses, and assessing any switching behavior over time, with analyses conducted using SAS Studio between the November 2023 and October 2024 timeframe.
Key findings: Initial coverage influences likelihood of switching
In this cohort study of 2,852 older adults (1,739 females, 1,113 males) a proportion of 31.52% without a history of cancer and 29.61% with a history of cancer switched Medicare coverage in the two years after initial plan selection. Sociodemographic and health-related characteristics were similar among beneficiaries with and without a history of cancer. For those with a history of cancer, they more likely to identify as White (301 beneficiaries [84.08%] vs 1,953 beneficiaries [78.31%]), have above a high school education (167 beneficiaries [46.65%] vs 941 beneficiaries [37.73%]), and report multiple comorbid conditions (225 beneficiaries [62.85%] vs 1,413 beneficiaries [56.66%]), when compared to those without a history of cancer.
Also, the initial selection of either Medicare Advantage or traditional Medicare with supplemental coverage was linked to a low likelihood of plan switching, regardless of cancer history.
“In this cohort study of older adults with and without a history of cancer, we found that those who initially selected either MA or TM plus supplemental coverage had a lower likelihood of switching Medicare coverage, compared with their counterparts who initially chose TM without supplemental coverage,” the researchers said. “Policymakers should consider improving the adequacy of TM coverage.”
Reference
1. Jazowski SA, Achola EM, Nicholas LH, et al. Medicare Plan Switching Among Beneficiaries With and Without a History of Cancer. JAMA Netw Open. 2025;8(6):e2513394. doi:10.1001/jamanetworkopen.2025.13394
