Lean Six Sigma interventions for enhancing patient safety-related outcomes: a systematic review

Purpose This study aims to systematically evaluate the effectiveness of Lean Six Sigma (LSS) methodologies in improving patient safety outcomes across diverse healthcare settings, addressing a critical need for structured, data-driven approaches to reduce harm and variation in care. Design/methodology/approach A systematic review of 26 peer-reviewed intervention studies published between 2015 and 2025 was conducted following PRISMA guidelines. The Quality Improvement Minimum Quality Criteria Set tool was used to analyze studies, and results were synthesized thematically across patient safety domains such as medication safety, surgical processes, infection prevention and diagnostic accuracy. Findings LSS interventions consistently improved key safety outcomes, with reductions in medication errors (up to 100%), surgical cancellations (−50%), and catheter-related infections. High-quality studies commonly used the Define-Measure-Analyze-Improve-Control framework and achieved more robust and significant results. However, the majority of studies were single-site, short-term and focused on process metrics rather than clinical outcomes. Research limitations/implications The evidence base is limited by a predominance of before–after designs and a lack of economic evaluation, limiting causal inferences and generalizability. Practical implications Healthcare organizations can prioritize LSS in high-impact domains like medication safety and diagnostics, while embedding sustainability measures such as control charts to monitor long-term outcomes. The findings provide an evidence-based roadmap for practitioners to implement LSS, highlighting critical success factors like leadership engagement and staff involvement. Social implications Expanding LSS research to low- and middle-income countries is essential to ensure equitable access to proven quality improvement strategies. Originality/value This review offers one of the most recent and comprehensive syntheses of LSS impact on patient safety, highlighting both effectiveness and persistent gaps in sustainability, methodological rigor and research diversity, especially in low-resource settings. It integrates insights from both healthcare and manufacturing literature to provide a holistic view of LSS applicability and evolution.