Impact evaluation of Lean Healthcare in emergency departments: evidence from a large-scale Brazilian initiative using difference-in-differences
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Background
Lean Healthcare has been adopted as an approach to reducing waste, enhancing process efficiency, and optimizing clinical and administrative workflows. However, empirical evaluations aimed at establishing a causal relationship between Lean Healthcare interventions and outcomes remain limited. This evidence gap is particularly pronounced in the context of large-scale implementations in low- and middle-income countries, where more efficient allocation could yield substantial improvements in population health.
Methods
We conducted an impact evaluation study employing a staggered difference-in-differences approach to estimate the effects of the Lean Healthcare in Emergency Departments (ED) initiative in the Brazilian context. The intervention was implemented between January 2017 and December 2025 across 309 hospitals. We analyzed hospital-level indicators of the number of hospitalizations and the average length of stay (in days) among patients admitted through urgent or emergency pathways.
Results
Our estimates suggest that the intervention was associated with an average increase of 38.6 admissions per hospital per month (p = 0.033), corresponding to approximately a 5.9% increase relative to the monthly admission volume. We also observed a reduction of 0.184 days in the average length of stay (p = 0.058), equivalent to an approximately 3.0% decrease in hospitalization time. These effects exhibited distinct temporal dynamics: the effect on the number of hospitalizations emerged gradually and increased with the duration of the intervention, whereas the reduction in length of stay became evident earlier.
Conclusion
This study provides evidence of a causal effect of Lean Healthcare implementation in emergency departments on operational performance. The simultaneous increase in admissions and reduction in length of stay suggests improved bed productivity and effective capacity without expanding physical infrastructure. These findings support the use of flow-management methodologies as an effective strategy for mitigating emergency department overcrowding while increasing service capacity.
What is already known on this topic
Lean Healthcare has been increasingly applied to healthcare service delivery and has been associated with measurable operational improvements in participating hospitals.
What this study adds
We employ a quasi-experimental design to assess the causal impact of Lean Healthcare in Emergency Departments (EDs). Our results indicate an increase in hospital admissions and a reduction in the average length of stay, resulting in increased hospital capacity.
How this study might affect research, practice or policy
Increased service capacity and reduced length of stay have implications for hospital capacity planning, suggesting that flow-management methodologies may increase effective capacity and reduce the need for costly physical bed expansion.
