Background and hypothesis Financial toxicity (FT) refers not only to the difficulty in affording medical care but also to the psychological distress and perceived financial burden it imposes. Although dialysis in Japan is extensively covered by public insurance, little is known about the prevalence of FT and its effects on medication adherence. This study aimed to assess the prevalence of FT and examine its association with medication adherence among patients undergoing haemodialysis in Japan.

Methods This multicentre, cross-sectional study included Japanese adults undergoing in-centre haemodialysis at six facilities. FT was assessed using the Comprehensive Score for Financial Toxicity (COST), and medication adherence was assessed using the 12-item Adherence Starts with Knowledge (ASK-12) scale. The COST scores were compared with published data from Japanese patients with cancer and patients undergoing dialysis from other countries using unpaired t-tests. Associations between the COST and ASK-12 scores were analysed using multivariate general linear models.

Results In total, 455 participants were included in the analysis. The mean COST score was 22.0, and 68% of the participants experienced at least mild FT. FT severity was comparable to that of Japanese patients with cancer and significantly lower than that reported among patients undergoing dialysis in Brazil and China. Lower FT (i.e., higher COST scores) was associated with fewer medication adherence difficulties (per 1-point higher: β = –0.19). This association was particularly evident in the ‘inconvenience/forgetfulness’ and ‘behaviour’ subdomains (per 1-point higher: β = –0.06 and β = –0.08, respectively).

Conclusions Despite generous public coverage, FT is common among Japanese patients undergoing haemodialysis and is associated with difficulties in medication adherence. The awareness of hidden financial distress and its integration into shared decision-making regarding prescriptions may help improve treatment adherence and patient outcomes.

What was known

Among patients undergoing dialysis, medication adherence rates are generally < 70%.

‘Financial toxicity’ is associated with poor medication adherence in oncology.

However, among patients undergoing dialysis receiving publicly funded care, the prevalence of financial toxicity and its effects on medication adherence remain unclear.

This study adds

Despite Japan’s comprehensive public insurance system, approximately 70% of patients undergoing dialysis experience at least mild financial toxicity levels, comparable to those observed in Japanese patients with cancer.

Lower financial toxicity was associated with better medication adherence, particularly in the ‘inconvenience/forgetfulness’ and ‘behaviour’ subdomains.

Potential impact

Financial hardship can cause stress. Healthcare providers should build trust with their patients and foster open discussions on financial and social challenges.

Practising shared decision-making is essential for prescribing medications that consider patients’ financial burden.

Providing work-friendly dialysis schedules may support patients’ long-term financial independence.

RI has received honoraria for speaking engagements and educational events from Astellas Pharma Inc., Novartis Pharma K.K., Otsuka Pharmaceutical and Vantive Japan. T.Toida has recieved consulting fees from Astellas Pharma Inc. He has also honoraria for speaking engagements and educational events from Torii Pharmaceutical Co., Ltd., Ono Pharmaceutical Co., Ltd., Kyowa Kirin Co.,Ltd., AstraZeneca K.K. Kissei Pharmaceutical Co., Ltd., and Nobelpharma Co., Ltd. T. Toishi received payment for speaking and educational events from Otsuka Pharmaceutical. MM has received payments for speaking and educational events from Astellas Pharma Inc. and Vantive Japan. TS has received payment for speaking and educational events from Astellas Pharma Inc, AstraZeneca K.K, Vantive Japan, Daiichi Sankyo Co.,Ltd., Janssen Pharmaceutical K.K, Kaneka Medix Corp, Kissei Pharmaceutical Co.,Ltd., Kowa Co.,Ltd., Kyowa Kirin Co.,Ltd, Mochida Pharmaceutical Co.,Ltd., Nobelpharma Co.,Ltd, Novartis Pharma K.K., Novo Nordisk Pharma.,Ltd., Ono Pharmaceutical Co.,Ltd., Otsuka Parmaceutical, Terumo Corp, and Torii Pharmaceutical Co.,Ltd. NK has received consulting fees from GlaxoSmithKline K.K. and Kyowa Kirin Co., Ltd. He has also received honoraria for speaking engagements and educational events from Eisai Co., Ltd., Taisho Pharmaceutical Co., Ltd., Kyowa Kirin Co., Ltd., GlaxoSmithKline K.K., Takeda Pharmaceutical Co., Ltd., Kissei Pharmaceutical Co., Ltd., and Vantive Japan.

This study was supported by the JSPS KAKENHI (grant numbers: JP19KT0021 and JP23K16271).

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study followed the Declaration of Helsinki and was approved by the Ethical Review Board of Fukushima Medical University (approval number: ippan2021-292).

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

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The datasets generated and/or analysed in the current study are available from the corresponding author upon reasonable request.