Assessing the Sleep-wake Pattern in Cancer Patients for Predicting a Short Sleep Onset Latency
Kikyoung Yi 1, Joohee Lee 2, Sungook Yeo 2, Kyumin Kim 2, Seockhoon Chung 2*
1Yongin mental hospital, 2Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine
Received: February 9, 2021; Revised: March 26, 2021; Accepted: May 11, 2021; Published online: May 11, 2021.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Objective: We investigated sleep parameters and clinical factors related to short sleep onset latency in cancer patients.
Methods: We retrospectively reviewed 235 cancer patients’ medical records. Patient Health Questionnaire-9, State and Trait Anxiety Inventory (State subcategory), Insomnia Severity Index(ISI), Cancer-related Dysfunctional Beliefs about Sleep, and Fear of Progression scale scores were collected. Sleep indices including sleeping pill ingestion time, bedtime, sleep onset time, and wake-up time were collected. These duration variables were calculated: durations from pills to bedtime, to sleep onset time, and to wake-up time; durations from wake-up time to bedtime and to sleep onset time; and time in bed in 24 h.
Results: Among cancer patients not taking sleeping pills (n = 145), early wake-up time (adjusted odds ratio [OR]: 0.39, 95% confidence interval [CI] 0.19-0.78), early sleep onset time (OR: 0.50, 95% CI 0.27-0.93), and low ISI score (OR: 0.82, 95% CI 0.71-0.93) were identified as the expecting variables for sleep latency ≤30 min. Longer duration from wake-up time to bedtime (OR: 2.49, 95% CI 1.48-4.18) predicted sleep latency ≤30 min. Among those taking sleeping pills (n = 90), early sleep onset time (OR: 0.54, 95% CI 0.39-0.76) and short duration from pills to sleep onset time (OR: 0.05, 95% CI 0.02-0.16) predicted sleep latency ≤30 min.
Conclusion: Cancer patients who fell asleep quickly showed less time in bed during the day. Before prescribing sleeping pills to cancer patients with insomnia, we should explore their sleep parameters to improve their sleep onset latency.
Keywords: insomnia, sleep parameters, cancer, sleep onset latency