Association between surgical start time and postoperative mortality, morbidity and healthcare utilisation in elective non-cardiac surgeries: a retrospective, single-centre study using propensity score matching.

Abstract

There is limited knowledge regarding the impact of surgical start time on postoperative outcomes in elective non-cardiac surgery. This study investigated the association between surgical start time and surgical outcomes in elective non-cardiac surgeries, including mortality; morbidity; and healthcare utilisation. We analysed 291,051 patients who underwent non-cardiac surgery. Patients were grouped by surgical start time: morning (08:00-13:00) vs. afternoon (13:00-18:00). Restricted mean survival time was calculated to assess survival differences. Outcomes were also stratified by weekday and season. Subgroup analyses evaluated associations between surgical timing and outcomes in high-risk populations, including older adults. After propensity score matching, statistically significant differences were observed between the morning and afternoon groups for 30-day mortality (0.12% vs. 0.17%, p = 0.015); 1-year mortality (2.73% vs. 3.36%, p < 0.001); composite complications (5.48% vs. 5.94%, p = 0.003); ICU admissions (5.87% vs. 7.18%, p < 0.001); and intra-operative transfusions (3.40% vs. 4.10%, p < 0.001). Restricted mean survival time analysis revealed significantly shorter survival times in the afternoon group across all time points. Afternoon surgery was associated with increased risk of 30-day mortality (adjusted hazard ratio 1.33, 95%CI 1.07-1.66, p = 0.010); 1-year mortality (adjusted hazard ratio 1.26, 95%CI 1.20-1.32, p < 0.001); composite complications (adjusted odds ratio 1.05, 95%CI 1.01-1.08, p = 0.010); ICU admission (adjusted odds ratio 1.09, 95%CI: 1.06-1.13, p < 0.001); and intra-operative transfusions (adjusted odds ratio 1.27, 95%CI 1.21-1.33, p < 0.001). Subgroup analysis indicated that the impact of surgical start time on outcomes was more pronounced in high-risk patients and also varied significantly depending on the type of surgery. Surgical start timing was an independent risk factor for increased short- and long-term postoperative mortality, morbidity and healthcare resource utilisation. The reasons for this are likely to be multifactorial.