Value-based outsourcing is associated with better environmental and economic sustainability metrics while maintaining patient safety: a comparative analysis of electricity use, water use, and prescription costs in public hospitals of Madrid (Spain)

Background Healthcare systems face growing pressure to maintain high-quality care while improving environmental and economic sustainability. Hospitals are resource-intensive institutions, contributing substantially to energy and water consumption, pharmaceutical expenditure, and healthcare-related greenhouse gas emissions. Value-based healthcare models, including value-based outsourcing of publicly funded hospitals to private networks, have shown promise in improving quality and efficiency. However, their impact on sustainability outcomes remains underexplored. This study compared environmental and economic sustainability indicators between value-based outsourced and publicly managed hospitals. Methods We conducted a cross-sectional comparative study using five years of administrative data (2019–2023) from 26 public hospitals in the Madrid Regional Healthcare Service, Spain. Four hospitals were managed by a value-based private network, and 22 were publicly managed. Outcomes included electricity consumption (kWh/m 2 per hospital stay), water consumption (m 3 per hospital stay), and mean unit cost of specialist-prescribed medications. Analyses were stratified by hospital complexity (low, medium, high) and adjusted for case-mix complexity and year of construction. Patient safety indicators (medical and surgical complications and hospital-acquired infections) were also compared. Statistical analyses used chi-squared, Student's t -test, or Mann–Whitney U tests, with p 0.05 considered significant. Results Outsourced hospitals treated patients with significantly higher overall case-mix complexity than publicly managed hospitals. Overall electricity consumption was lower in outsourced hospitals (0.009 vs. 0.011 kWh/m 2 per hospital stay; p = 0.039), leading to estimated cost savings of 1,648,305 € and an approximate reduction in greenhouse gas emissions of 8,672 CO2 metric tons during the study period, as was water consumption (0.65 vs. 0.81 m 3 per hospital stay; p 0.001). The mean unit cost per medication was also lower in outsourced hospitals (€21.45 vs. €22.92; p = 0.026), with significant differences primarily in medium-complexity hospitals. Outsourced hospitals demonstrated slightly but significantly lower rates of inpatient complications and hospital-acquired infections. Conclusions Value-based outsourcing in Madrid's public hospitals was associated with improved environmental and economic sustainability, alongside favorable patient safety outcomes, despite higher case-mix complexity. These findings support incorporating sustainability indicators into performance-based healthcare models and suggest value-based outsourcing as a potential strategy to advance sustainable healthcare delivery.