The healthcare sector contributes approximately 8.5% of U.S. greenhouse gas emissions, underscoring the need for health systems to lead in sustainability and climate resilience initiatives. While the Planetary Health Report Card (PHRC) has advanced the integration of planetary health principles into medical education, the sustainability practices of affiliated hospitals remain largely unexamined. This study evaluates whether the environmental commitments of PHRC-participating medical schools align with the practices of their primary and secondary hospital affiliates.

Publicly available data were analyzed for 66 primary and 65 secondary affiliates of PHRC-participating medical schools in the U.S. A Green Scorecard was developed based on 12 weighted sustainability indicators across three tiers reflecting projected environmental impacts at a systems level. Associations between hospital sustainability performance and medical school PHRC scores were assessed using Pearson correlation coefficients, chi-square analyses, and independent-samples t -tests.

Primary affiliates demonstrated significantly higher sustainability performance than secondary affiliates (Average Green Scorecard result 39.6 vs. 30.4, p = 0.006). A weak but statistically significant positive correlation was observed between higher PHRC grades and greener hospital practices (r = 0.26, p = 0.003). Primary affiliates were significantly more likely to have decarbonization targets for 2050 or earlier (67% vs. 20%, p < 0.001), clean energy practices (91% vs. 61%, p < 0.001), LEED Gold certification (33% vs. 20%, p = 0.015), Environmental, Social, and Governance (ESG) goals (82% vs. 66%, p = 0.041), and clean transportation initiatives (64% vs. 40%, p = 0.007). With leadership structures, 48% of primary affiliates had a sustainability officer compared with 39% of secondary sites. Although operational measures such as recycling (86%), green chemical use (45%), and plant-based diets (53%) were relatively common, high-impact structural interventions remained less uniformly implemented.

Hospitals affiliated with medical schools prioritizing planetary health education exhibit stronger sustainability performance, suggesting alignment between academic medicine and affiliated healthcare systems. Substantial variability and data gaps highlight the need for standardized reporting, regulatory guidance, and equitable investment in sustainability infrastructure across hospital systems. Expanding transparency, accountability, and leadership capacity will be essential for transforming hospitals from contributors to climate change into anchors of resilience and planetary health.