Diminished rest-activity rhythm is associated with postoperative complications and mortality: A prospective cohort study of UK Biobank participants.

Background: Circadian rhythm disruption, as a modifiable risk factor, has been increasingly recognised for its potential impact on adverse health outcomes, particularly in surgical populations where its implications warrant further investigation.

Objectives: To investigate associations between postoperative outcomes and preoperative rest-activity rhythm metrics from accelerometry.

Design: A cohort analysis of UK Biobank participants undergoing major surgery within 1 year of accelerometer monitoring.

Setting: UK Biobank, a large population-based cohort in the United Kingdom.

Patients: These were 5654 adults (37 to 73 years) completing 7-day preoperative wrist accelerometry.

Exposure: Rest-activity rhythm relative amplitude was analysed both as a continuous variable and as a categorical variable. For the categorical analysis, a low relative amplitude group was defined as more than 2 standard deviations below the cohort mean: all other participants served as the high relative amplitude group.

Main Outcome Measures: The primary composite outcome included 30-day postoperative complications and 90-day mortality. Multivariable logistic regression was used to adjust for comorbidities, demographics and surgical risk factors.

Results: Participants with a low relative amplitude (n = 225) demonstrated significantly higher rates of adverse outcomes compared with the remainder of the participants (n = 5429), with an absolute risk difference of 6.1% (9.8 vs. 3.7%), P < 0.001). Multivariable analysis revealed a dose-response relationship: each standard deviation decrease in relative amplitude increased risk by 23% {adjusted odds ratio, aOR: 1.23 [95% confidence interval (CI), 1.06 to 1.42]}. The low amplitude group had double the risk of adverse outcomes compared with the remainder of the participants: adjusted OR: 2.16 (95% CI, 1.25 to 3.73).

Conclusions: A lower preoperative circadian relative amplitude is associated with increased postoperative morbidity and mortality. Accelerometry-based circadian monitoring may provide a novel, cost-effective strategy for preoperative risk stratification.