Profile and predictors of subjective-objective sleep discrepancy in individuals with poor sleep quality

This study aimed to investigate the profile, correlates, and predictors of subjective-objective sleep discrepancy (SOSD) in total sleep time (TST) in individuals with poor sleep quality, with a focus on contrasting clinical characteristics with and without TST misperception.

From the Chinese Clinical Sleep Database, 487 participants with poor sleep quality who had completed polysomnography and questionnaires were included in the analyses. SOSD was calculated as the raw difference between objective TST (oTST) and subjective TST (sTST) [oTST - sTST], where positive values represent underestimation. Correlation analysis was carried out to examine the bivariate relationship between SOSD and other study variables. Participants were further categorized by their SOSD as: normoestimators (-2 to 2 h), underestimators (≥2 h), or overestimators (≤-2 h). Bivariate and logistic regression were used among normoestimators and underestimators to assess associations between SOSD and demographic, psychometric, and sleep-related factors.

The study included 487 participants with poor sleep quality (median age: 35 years; 52.2% male), demonstrating significant discrepancies between subjective and objective sleep measures. Bland-Altman analysis revealed systematic underestimation of TST (mean discrepancy: 0.97 ± 2.20 h), with strong correlations between SOSD and poorer sleep quality, objective TST (all p < 0.05). Underestimators (24.6% of participants) were older, less likely to nap, less educated, and unemployed (all p < 0.05), reporting worse subjective sleep despite objectively longer TST and higher efficiency (p < 0.05). Logistic regression identified lower education, town residence, and lack of habitual napping as significant predictors of SOSD. After additional adjustment for polysomnographic sleep continuity measures, these associations remained stable.

This study highlights significant discrepancies between subjective and objective sleep measures in individuals with poor sleep quality, with systematic underestimation of sleep duration linked to demographic and socioeconomic factors. The findings underscore the importance of addressing sleep misperception in clinical evaluations, particularly among older, less educated populations, while emphasizing that habitual napping was associated with lower odds of underestimation.