The Paradox of Access: How Increased Generic Drug Availability Affects Patient Adherence
(A2026-131724)

AUTHORS

Jiancai Liao, University of Birmingham; Chuhan Liu, Analysis Group; Jian Ni, Virginia Tech

ABSTRACT

Rising healthcare costs drive generic drug promotion to reduce expenses and improve accessibility. However, their impact on patient adherence is underexplored. This paper examines how increased drug availability affects patient adherence via China’s 4+7 volume-based procurement policy. Our findings show greater generic availability correlates with lower adherence, reflected in a 0.74-day therapy delay in pilot cities. Heterogeneity analysis reveals adherence declines were less pronounced for drugs from manufacturers with stronger market power, longer market presence, higher active ingredient ratios, and international branding. Using a causal machine learning model, we further find steep price reductions exacerbate non-adherence. Theoretically, this study challenges the view that greater drug availability improves patient outcomes. Practically, we offer insights for firms to sustain adherence and recommend policymakers balance cost savings with adherence for optimal health outcomes.