Background: “Post hospital” syndrome is a critical period after discharge when patients are at risk of functional decline and re-admission. Two factors implicated in the development of this syndrome are sleep disturbance and low physical activity; both of which are known hazards from hospitalization. To date, no study uses rigorous objective methods to describe how sleep and activity levels vary after discharge in older patients who were discharged from a general medicine ward. Understanding these patterns could inform interventions to address post-hospital syndrome. Our study aims to objectively characterize daytime activity, sleep duration, and sleep efficiency among patients during hospitalization and post-discharge.
Methods: Eligible patients for this study were over the age of 50, discharged home, community dwelling, ambulatory, and without an ICU stay or known sleep disorder. Eligible patients wore a wrist accelerometer that measured activity and sleep for at least one in-hospital night and two post-discharge nights. Objective physical activity (average activity counts/minute), sleep duration (minutes), and sleep efficiency (% time asleep over time in bed) were measured by wrist accelerometers. Upon enrollment, baseline sleep duration was determined by the Pittsburgh Sleep Quality Index (PSQI) and baseline daytime sleepiness was determined by the Epworth Sleepiness Scale (ESS). Length of stay and demographics were collected from charts. Descriptive statistics were used to summarize data. Random effect linear regression models clustered by subject were used to test associations between sleep duration, sleep efficiency, and daytime physical activity before and after hospitalization and for each day of the study.
Results: From October 2012 to July 2015, 196 nights and 189 activity periods were recorded from the 27 patients who consented to the study. Most patients were African American (88.5%), female (63.0%), with a median length of stay in the hospital of 3.0 days (IQR=1.7-4.3). Upon admission, mean ESS was 8.2 ± 5.3 with 40.7% categorized as excessively sleepy. Prior to hospitalization, mean self-reported sleep duration was 373.8 ± 105.6 minutes. There was no significant difference between mean in-hospital and post-discharge sleep duration (346.8 ± 112.8 minutes vs. 339.5 ± 135.3 minutes, 95% CI [-28.1, 35.0], p=0.83) or sleep efficiency (74.8± 15.8% vs 69.5 ± 20.3%, 95% CI [-8.5, 1.3], p=0.15). Compared to in-hospital daytime activity at 144.6 ± 80.0 counts/minute, corresponding to sitting while eating, patients had higher activity levels post-discharge at 207.5 ± 112.5 counts/minute, corresponding to sitting while active with hands (+53.7 counts/minute, 95% CI [30.3, 77.1], p<0.01). In a multivariable regression model clustered by subject, post-discharge sleep did not increase for each day in the study (-0.6 minutes, 95% CI [-5.9, 4.8], p=0.84). However, patients had higher daytime physical activity for each day in the study (+11.9 counts/minute, 95% CI [7.8, 16.0], p<0.01).
Conclusions: Although hospitalization is associated with acute sleep loss, patients did not receive more sleep post-discharge. Patients’ activity levels do improve after discharge, suggesting improved physical function. It is important to investigate if patient sleep is eventually restored after discharge or if hospitalization is associated with chronic sleep disorders. Future research on how trajectories could predict patient outcomes is warranted.