Sleep and Circadian Health of Critical Survivors: A 12-Month Follow-Up Study*

Abstract

Objectives: To investigate the sleep and circadian health of critical survivors 12 months after hospital discharge and to evaluate a possible effect of the severity of the disease within this context. Design: Observational, prospective study. Setting: Single-center study. Patients: Two hundred sixty patients admitted to the ICU due to severe acute respiratory syndrome coronavirus 2 infection. Interventions: None. Measurements and Main Results: The cohort was composed of 260 patients (69.2% males), with a median (quartile 1–quartile 3) age of 61.5 years (52.0–67.0 yr). The median length of ICU stay was 11.0 days (6.00–21.8 d), where 56.2% of the patients required invasive mechanical ventilation (IMV). The Pittsburgh Sleep Quality Index (PSQI) revealed that 43.1% of the cohort presented poor sleep quality 12 months after hospital discharge. Actigraphy data indicated an influence of the disease severity on the fragmentation of the circadian rest-activity rhythm at the 3- and 6-month follow-ups, which was no longer significant in the long term. Still, the length of the ICU stay and the duration of IMV predicted a higher fragmentation of the rhythm at the 12-month follow-up with effect sizes (95% CI) of 0.248 (0.078–0.418) and 0.182 (0.005–0.359), respectively. Relevant associations between the PSQI and the Hospital Anxiety and Depression Scale (rho = 0.55, anxiety; rho = 0.5, depression) as well as between the fragmentation of the rhythm and the diffusing lung capacity for carbon monoxide (rho = –0.35) were observed at this time point. Conclusions: Our findings reveal a great prevalence of critical survivors presenting poor sleep quality 12 months after hospital discharge. Actigraphy data indicated the persistence of circadian alterations and a possible impact of the disease severity on the fragmentation of the circadian rest-activity rhythm, which was attenuated at the 12-month follow-up. This altogether highlights the relevance of considering the sleep and circadian health of critical survivors in the long term.