The sleep log and actigraphy: Congruency of measurement results for heart failure patients

Background: Quality of life in patients with heart failure (HF) can be significantly impacted by poor sleep and its daytime consequences. As more attention is being paid to the sleep problems of HF patients, it is important to evaluate the degree of congruence between subjective and objective sleep measurements in this patient group. Purpose: This study was developed to evaluate the congruence between sleep parameters as measured using a wristworn ActiGraph and a daily sleep log in patients with stable HF. Methods: Forty-three HF patients aged 40-92 years served as subjects. Sleep parameters were derived from actigraphy and a daily sleep log by averaging scores for 7 nights. Results: There were significant differences in wake time after sleep onset (WASO) and total sleep time between the sleep log and the ActiGraph (both ps <.001). Neither WASO nor sleep onset latency, both derived from the sleep log, correlated significantly with actigraphy variables. The mean bias for WASO and total sleep time between methods was 54.1 min (SD = 47.5 min) and 109.3 min (SD = 91.68 min) as assessed using a Bland-Altman analysis. A majority (83.7%) of participants experienced sleep disturbances as assessed by actigraphy. However, fewer (53.5%) had sleep disturbances as assessed using the sleep log. Conclusion: A considerable degree of incongruence between actigraphy- and sleep log-derived measures of sleep exists in patients with stable HF.