The Impact of Out-of-Hours Liver Transplantation on Outcomes: A Swedish National Study.

Abstract

This national, multicenter retrospective study of 764 adult liver transplantations (LT) in Sweden (2019-2023) employed a data-driven approach to identify the out-of-hours (OOH) high-risk window and evaluate its impact on patient outcomes and health care costs. LT logistics often necessitate OOH surgery, but the evidence for an impact on outcomes remains conflicting, partly due to arbitrary window definitions. Using the mathematical principle of permutations and linear regression analysis of 1-hour start-time intervals across 552 temporal windows, we identified the period with the greatest impact on the primary endpoint: the 3-month Comprehensive Complication Index (CCI). Secondary outcomes included intensive care unit length of stay, Clavien-Dindo complications, reoperations, patient and graft survival, and health care costs. The 17:00 to 05:59 window was identified as having the greatest negative impact on CCI. After adjusting for covariates, procedures initiated during this timeframe were associated with significantly higher CCI (β=7.41, 95% CI: 4.27-10.56, P<0.01), increased Clavien-Dindo IIIb and IV complications, 1.16 days longer intensive care unit stay and a higher risk of LT-related reoperations (odds ratio: 1.61, 95% CI: 1.11-2.36). One-year graft and patient survival were comparable between groups. Health care costs were 169.629 SEK (€15,500) higher per patient operated OOH, during the 3-month follow-up. This data-driven analysis identified a high-risk OOH window beginning earlier than previously reported (17:00 vs. traditional nighttime definitions). LT starting in this interval is associated with significantly increased morbidity and health care costs. Further studies are needed to evaluate mitigating strategies to enable daytime transplantation.