Low repeatability of Epworth Sleepiness Scale after short intervals in a sleep clinic population

Abstract

Study Objectives: The purpose of this study was to evaluate the short-term repeatability of the Epworth Sleepiness Scale (ESS) in patients with suspected obstructive sleep apnea and to determine whether transitory sleepiness of the patient influenced ESS results. Methods: Adult participants with suspected obstructive sleep apnea taking part in a study on the diagnostic accuracy of repeated sleep studies were eligible. For assessment of repeatability, the agreement between 2 sequential ESS scores obtained within 1 day (same-day group) or on different days within 1 week (same-week group) was evaluated. By analyzing the within-day repeatability, a possible influence of situational sleepiness on ESS results was assessed. By comparing correlations of sequential scores between both groups, a potential influence of test day-specific sleepiness on ESS results was evaluated. Data were analyzed using Bland-Altman plots, intraclass correlation coefficients, standard error of measurement analysis, and relative amounts of ESS discrepancies beyond 2, 3, 5, and 7 points. Results: Forty participants (mean age, 47.7 ± 15.4 years; 67.5% men) were included in this study, with 20 in each group. Bland-Altman analysis demonstrated considerable variability of repeated scores (mean ± 1.96 × SD = 1.93 [−3.81 to 7.66]). Discrepancies of at least 3 points between sequential ESS scores were found in 48% of all participants. Comparison of ESS repeatability between both groups showed no evidence for a difference. Conclusions: A clinically relevant variability in ESS scores was found, even when repeated on the same day, possibly because of situational sleepiness influencing ESS results. Changes in ESS in response to interventions should be interpreted with caution because of its low test-retest reliability.

How sleepy patients differ from non‐sleepy patients in mild obstructive sleep apnea?

“…This is because it has been shown that ESS alone may not be enough to evaluate daytime sleepiness (Thorarinsdottir et al, 2019). The ESS is known for its low repeatability and test–retest reliability even during a single day (Campbell et al, 2018; Grewe et al, 2020), and its low sensitivity and specificity to identify the presence of OSA (AHI ≥ 5) highly depends on the used ESS cut‐off value (Rosenthal & Dolan, 2008). Among the general population, the median ESS was found to be 6 points (Stradling et al, 2000), while among patients with OSA the score was 7.8, 8.3 and 9.3 for mild, moderate and severe OSA, respectively (Gottlieb et al, 1999).…”

Residual excessive daytime sleepiness in patients treated for obstructive sleep apnea: guidance for assessment, diagnosis, and management

“…Accuracy may be enhanced when the ESS is completed as a consensus between the patient and partner [46]. Recent data have questioned the reliability of the ESS [43,44,47,48]. One study found variability in ESS scores even when the assessment was repeated on the same day, suggesting that situational sleepiness (i.e.…”

“…One study found variability in ESS scores even when the assessment was repeated on the same day, suggesting that situational sleepiness (i.e. time of test administration) may influence ESS scores [48].…”

Low repeatability of the Epworth Sleepiness Scale and the need to redefine the minimal clinically important difference

“…Grewe et al 1 have raised questions about the commonly used Epworth Sleepiness Scale (ESS) in medicine. They report discrepancies of at least 2 points between sequential ESS scores that occurred in 63%, at least 3 points in 48%, at least 5 points in 20%, and at least 7 points in 8% of the total of 40 participants.…”