How Disease-Modifying Therapies Challenge Dementia Care Continuity in Japan: From Promise to Paradox

Abstract

Management of Alzheimer's disease has entered a new phase with the advent of disease-modifying therapies (DMTs). Anti-amyloid beta antibodies used in DMTs—such as aducanumab, lecanemab, and donanemab—differ from earlier medications in that they slow cognitive decline by reducing amyloid plaque accumulation in the brain [1]. As Belder noted, the introduction of DMTs is expected to increase the demand for clinical services, necessitating systems that ensure timely and equitable access to these therapies [2].

Despite the demonstrated efficacy of DMTs, there are concerns remain regarding their cost-effectiveness. Their adoption has been limited in the United States, and they have not yet been approved in the European Union. In contrast, the Japanese government has taken a proactive stance toward promoting the use of DMTs. Japan's universal health insurance system allows patients to access treatment with minimal out-of-pocket costs if they meet specified criteria [3]. However, implementing DMTs within this system requires careful planning to avoid disruptions and ensure equitable delivery.

Our institution was tasked with advising the Tokyo Metropolitan Government to establish a delivery system for DMTs. We initially anticipated that expanding therapeutic options would lead to earlier diagnoses, thereby increasing the number of patients requiring post-diagnostic support. However, we have encountered an unintended consequence: the implementation of DMTs is, in some cases, impeding the provision of post-diagnostic support. We share this experience with the global scientific community.

The philosophy underlying Tokyo's DMT delivery system is based on the following principles [4]: diagnosis and treatment require confirmation of amyloid pathology and the capacity to monitor and manage amyloid-related imaging abnormalities (ARIA) throughout an 18-month treatment course. Therefore, only hospitals equipped with PET and MRI scanners and staffed by certified neurologists were designated as DMT-initiating hospitals. When primary care physicians (typically based in clinics) suspect that a patient is eligible for DMT, they refer the patient to an initiating hospital. In Tokyo, medical centers for dementia (MCDs), government-certified hubs for dementia care, serves as either DMT-initiating hospitals or as collaborating hospitals that support DMT-initiating institutions.

With the increasing number of patients starting DMTs, hospitals have exceeded their capacity. Consequently, patients are transferred after 6 months to less-equipped “DMT-continuing clinics,” usually smaller institutions or clinics. These continuing clinics take over day-to-day care while DMT-initiating hospitals remain responsible for periodic MRIs, cognitive assessments, and managing serious side effects, such as ARIA. Thus, a two-tiered system (Figure 1) was established to balance the need for specialized care with universal accessibility.

Although primary care physicians are not directly involved in the DMT administration, they maintain long-standing relationships with patients and their families. These physicians are well-positioned to support shared decision-making by considering patients' life histories, family dynamics, and comorbidities, which are factors that are crucial to the overall quality of life. Such patient-centered, recovery-oriented support is central to effective post-diagnostic care. However, once patients begin DMT, their dementia care tends to shift to the medical institution administering the DMT, often interrupting the involvement of the primary care physician in post-diagnostic support.

Moreover, because DMT-initiating hospitals are also MCDs, which are institutions responsible for post-diagnostic support, patients receive this support during the initial treatment phase. However, our interviews with staff from some DMT-continuing clinics revealed that they intentionally refrained from providing post-diagnostic support. This reluctance stems from concerns about disrupting the existing patient-provider relationship. In Japan, which lacks a general practitioner system, patients are free to consult any medical facility. In tight-knit local medical communities, switching primary care providers is sometimes perceived as “stealing patients,” leading some clinicians to avoid providing supportive care that might attract patients away from their original physicians. As a result, a discontinuity in post-diagnostic support often occurs after patients are transferred to DMT-continuing clinics.

It remains unclear whether this situation is widespread or limited to certain areas. Nonetheless, it is important to highlight this paradox: a delivery system designed to ensure the safe and equitable use of DMTs may inadvertently contribute to gaps in post-diagnostic support. This finding warrants broader discussion in the context of dementia care system reform.

The study was approved by the Research Ethics Board of the Tokyo Metropolitan Institute of Gerontology (R24-121).

The authors declare no conflicts of interest.