Longitudinal trajectories of sleep inertia among intern nurses with shift work in China: Prevalence, risk factors and outcomes

There is a growing consensus regarding the significant individual differences in responses to sleep inertia. However, little is known about the longitudinal trajectories of sleep inertia. Therefore, we aimed to investigate the incidence rates of sleep inertia, longitudinal trajectories, influencing factors and outcomes among intern nurses with shift work. A total of 1079 intern nurses with shift work completed online surveys at 2 weeks (T1) and 16 weeks (T2) after their clinical internship, respectively. The demographics and willingness to continue working as nurses, circadian type, sleep problems and emotional problems were measured. Hierarchical logistic regressions were used to examine predictors for the distinct longitudinal trajectory of sleep inertia, and binary logistic regressions were used to examine the predictive effects of trajectory memberships of sleep inertia on mental health problems (daytime sleepiness, anxiety, depression) at follow-up. Overall, the incidence rates of severe sleep inertia increased significantly from 20.4% at T1 to 25.3% at T2 among intern nurses with shift work. All participants were classified into four trajectory memberships. Multiple factors were significant predictors of distinct trajectories of sleep inertia. Additionally, individuals with deteriorated and persistent-high sleep inertia were more likely to develop mental health problems at the subsequent point. Sleep inertia is prevalent among intern nurses with shift work, and its distinct change patterns were associated with multiple risk factors and various adverse outcomes. Therefore, these factors should be considered when designing individualized and appropriate interventions for sleep inertia among medical staff.