Discrepancy between desired time in bed and desired total sleep time in patients with cancer: The DBST index and its relationship with insomnia severity and sleep onset latency

Abstract

Patients with cancer can often experience insomnia or sleep disturbances. This study aimed to explore whether the discrepancy between a patient’s desired time in bed and desired total sleep time (DBST index) can be used as a measurement tool for insomnia severity or sleep onset latency [SOL] in patients with cancer. This retrospective medical records review study gathered clinical information and scores from scales and indices such as the Insomnia Severity Index (ISI), Cancer-related Dysfunctional Beliefs about Sleep (C-DBS) scale, Patient Health Questionnaire-9 items (PHQ-9), State subcategory of State and Trait Anxiety Inventory, and the short form of the Fear of Progression Questionnaire. Sleep indices of time variables (bedtime, sleep onset time, and wake-up time), duration variables [SOL, time in bed (TIB), time in bed over 24 hours (TIB/d), and duration from wake-up time to bedtime (WTB)], and DBST index were calculated. ISI scores were predicted by the PHQ-9 (β = 0.34, P < 0.001), C-DBS scale (β = 0.17, P = 0.034), and DBST indices (β = 0.22, P = 0.004). Long SOL value was predicted by early bedtimes (β = −0.18, P = 0.045), short WTB durations (β = -0.26, P = 0.004), and high DBST index values (β = 0.19, P = 0.013). The DBST index was significantly correlated with both insomnia severity and SOL in patients with cancer.

No Association Between Insomnia Severity, and Discrepancy Between Desired Time in Bed and Desired Total Sleep Time Among Shift-Working Nursing Professionals

“…In a previous study of the general population [9], the DBST index was associated with insomnia severity and preoccupation with sleep, while preoccupation with sleep mediated the influence of dysfunctional beliefs about sleep and the DDBST index on insomnia severity. Among cancer patients [10], the DBST index was significantly associated with insomnia severity and sleep onset latency. However, we observed that contrary to expectation, the DBST index in two groups of healthcare workers was not significantly correlated with insomnia severity.…”

“…It is made up of 7 items in total, where a 5-point Likert scale is used to rate each item, and where a higher total score indicates a more severe degree of insomnia. The scores are interpreted as follows: absence of insomnia (0-7); sub-threshold insomnia (8)(9)(10)(11)(12)(13)(14); moderate insomnia (15-21); and severe insomnia (22-28).…”

“…The DBST index depends on the idea that people who suffer from insomnia want to sleep more and fall asleep earlier. They tend to go to bed earlier in the evening but wake up late in the morning as they struggle to fall asleep [9,10].…”

“…The relation of the DBST index to insomnia severity among the general population has already been explored [9], and also among cancer patients [10], who frequently suffer from insomnia during their cancer diagnosis and treatment trajectory. In contrast, no previous study has explored the relationship between the DBST index and the severity of shift workers' insomnia.…”

Efficacy and safety of digital therapeutic application of Sleep Index‐Based Treatment for Insomnia (dSIBT‐I): a pilot study

“…The SIBT‐I uses sleep patterns obtained from clinical practice to guide the proper sleep–wake cycle. It comprises the following four concepts: (1) 17 h of activity and 7 h of sleep (Chung et al, 2018), (2) discrepancy between desired time in bed (TIB) and desired total sleep time (TST; the DBST index; Cho et al, 2022; Chung, 2022a; Lee et al, 2022), (3) TIB during 24 h (Zhou et al, 2017), and (4) taking sleeping pills 7 h before the waking‐up time (Chung et al, 2016).…”