価格を見せる：価格顕示性、流動性制約、および償還型医療制度設計 日本とスウェーデンからのエビデンスと政策的含意

Abstract / 要旨

本稿について

本稿は、日本の外来受診過剰利用問題に対して、価格水準ではなく費用の可視性(サリエンス)と流動性制約に着目した代替的政策フレームワークを提示するワーキングペーパーである。

現行の現物給付方式では患者が自己負担分しか認識しないため、サリエンスの低下を通じたモラルハザードが誘発される。本稿はこれに対し、軽症外来については患者が全額を先払いすることで費用を可視化し、高額医療については現物給付に自動移行するハイブリッド型償還払いモデルを提案する。マイナンバー連携によるリアルタイム償還インフラとの組み合わせにより、流動性制約への対応も組み込む。日本・スウェーデン比較およびShigeoka(2014)の回帰不連続分析を実証的根拠として援用する。

本稿はまた、患者先払い方式がプロバイダーの診療報酬回収遅延を短縮するという供給サイドへの含意についても論じる。

公開の目的

本稿はXおよび関連コミュニティにおける批評・アイデアの収集を主目的として公開する。著者への意見・コメントはX(@cavid19w)または本レコードのコメント欄で受け付ける。

バージョン情報

• v1.2(本版):日本語版ワーキングペーパー
• v2.0(予定):英語版への改訂・拡充版を同一DOIにて登録予定

This is a Japanese-language working paper. A revised English version is planned as v2.0 under the same DOI.

著者

九条丈二(George Kujo) 独立研究者・政策評論家 ORCID: 0009-0006-6864-0145

English

Healthcare overutilization remains a persistent concern in high-income countries, particularly in systems with low point-of-service cost sharing. Japan exemplifies this issue, recording among the highest outpatient visit rates in the OECD despite achieving health outcomes broadly comparable to Sweden, where utilization is substantially lower. Conventional policy responses have focused on increasing cost-sharing or introducing gatekeeping mechanisms; however, both approaches face substantial political and institutional constraints in the Japanese context.

This paper proposes an alternative framework grounded in the timing and salience of healthcare payments. We argue that healthcare demand is shaped not only by the level of cost-sharing but also by the degree to which costs are visible at the moment of the consumption decision, and by the liquidity constraints patients face when full payment is required upfront. Under conventional in-kind benefit systems, patients observe only a fractional co-payment, potentially inducing moral hazard through reduced price salience.

We introduce a hybrid reimbursement-based model in which patients initially pay the full cost of low-acuity outpatient care—thereby making prices fully salient—while high-cost treatments automatically transition to in-kind coverage to preserve financial protection. This design operationalises the principle of ex-ante discipline combined with ex-post insurance. We further propose integrating digital identity-linked infrastructure to enable real-time reimbursement and individualized cost thresholds, mitigating liquidity constraints and administrative burdens.

Drawing on cross-country comparisons between Japan and Sweden and on causal evidence from studies exploiting cost-sharing discontinuities—most notably Shigeoka (2014)—we argue that substantial reductions in low-value outpatient utilization may be achievable without significant deterioration in population health outcomes. We additionally highlight a novel supply-side implication: improved provider cash flow through reduced reimbursement delays under digitally mediated patient-pay-first arrangements.

The paper contributes to the health economics and health policy literatures by reframing healthcare payment design as a joint problem of price, salience, and financial intermediation. Potential risks—including delayed care-seeking, equity concerns, and implementation challenges—are discussed in detail.