IMPORTANCE: Sleep timing regularity is increasingly recognized as a determinant of cognitive performance, yet its influence on surgeons' well-being and patient safety remains unexplored.
OBJECTIVE: To evaluate the association between surgeons' sleep timing regularity and major adverse events in their patients.
DESIGN, SETTING, AND PARTICIPANTS: This multicenter prospective cohort study was conducted from November 1, 2020, to December 31, 2021, across 14 surgical departments in 7 specialties at 4 university hospitals in France. Patients were excluded if they were younger than 18 years, underwent palliative surgery, had incomplete operative time stamps, or were operated on by surgeons with invalid sleep data. Study data were analyzed from January to June 2025.
EXPOSURES: Surgeons' sleep was continuously monitored using actigraphy. Sleep timing regularity in the 30 days preceding surgery was quantified using midsleep time (midpoint between bedtime and get-up time). Social jet lag (SJL) was defined as the absolute difference between midsleep times on free days and workdays, and midsleep time variability was the SD of daily midsleep times.
MAIN OUTCOMES AND MEASURES: Outcomes included major adverse events within 30 days postoperatively, including inpatient death, prolonged intensive care unit stay, reoperation, or severe complications. Mixed-effects multivariable models were adjusted for surgeon sleep duration, midsleep time, age, sex, professional status, working hours, night shifts, patient case mix (ie, a composite risk score incorporating patient comorbidities and surgery characteristics), and time of incision, with a random effect for surgeons. Surgeon burnout was assessed using the Maslach Burnout Inventory.
RESULTS: Among 7117 operations (7117 patients; mean [SD] age, 55.9 [17.5] years; 3877 female [54.5%]) performed by 38 attending surgeons (mean [SD] age at study start, 46.1 [8.5] years; 30 male [79%]), 1410 (19.8%) resulted in a major adverse event. SJL of 2 or more hours (342 operations [4.8%]; 7 surgeons) was associated with increased risk of major adverse events compared with less than 1 hour (adjusted relative risk [RR], 1.36; 95% CI, 1.04-1.69) and 1 to 2 hours (RR, 1.45; 95% CI, 1.12-1.81). Midsleep time variability of 60 minutes or longer (864 operations [12.1%]; 20 surgeons) was not associated with adverse outcomes. Surgeons with burnout had higher median [IQR] social jet lag (75 [47-94] vs 52 [38-61] minutes; P = .04) and midsleep time variability (54 [44-68] vs 43 [36-48] minutes; P = .01) than those without burnout.
CONCLUSIONS AND RELEVANCE: Patients operated on by surgeons experiencing substantial social jet lag had a higher associated risk of major adverse events. Interventions promoting regular sleep timing and reducing circadian misalignment may improve surgeon burnout and patient safety.
