Comorbidity, Polypharmacy, and Aging in Multiple Sclerosis

As age increases, the prevalence of comorbidities increases in the general population. In turn, this often leads to an increase in the number of medications administered. This phenomenon creates additional challenges in the management of neurodegenerative disorders such as multiple sclerosis (MS). Higher comorbidity burden is associated with longer diagnostic delays and greater disability at diagnosis. A higher burden of comorbidities in people with MS is associated with higher disability levels and accelerated disability progression. Responses to rehabilitation therapy may also be altered in terms of timing and sustainability of response. Conversely, a diagnosis of MS negatively affects the management and outcomes of some comorbidities, and treatment of certain comorbidities can worsen MS symptoms. Thus, comorbid conditions in people with MS have important implications with respect to MS-specific care and general health care throughout the life course of the disease. Comorbidities must be considered when developing plans of care. Similarly, polypharmacy is common in non-MS populations, even more so in MS populations, and can adversely affect quality of life and worsen underlying disability. In 2023, the Consortium of Multiple Sclerosis Centers needs assessment identified comorbidity and polypharmacy as a core topic relevant to the care of aging adults with MS, and an in-person meeting of experts in 2024 discussed the existing literature. This narrative review discusses how comorbid disease and polypharmacy affect people with MS, strategies to mitigate these negative risks, as well as areas where evidence is lacking and further study is needed to inform optimal treatment strategies for older adults with MS.