From the Journals

Single-item scale effective for assessing sleep quality



The single-item sleep quality scale (SQS) produced favorable results comparable to other complex, time-intensive assessment tools, according to findings published in the Journal of Clinical Sleep Medicine.

Sleeping elderly woman Silvia Jansen/iStockphoto

In a study of 70 insomnia patients and 651 depression patients, concurrent criterion validity analysis yielded strong correlations between the SQS and the morning-questionnaire insomnia (MQI) and Pittsburgh Sleep Quality Index (PSQI) in patients with insomnia and depression, respectively. The investigators wrote, “The single-item format enables a patient-reported rating of sleep quality over a 7-day recall period without greatly increasing the patient’s burden. The use of a discretizing visual analog scale (VAS) increases the potential for a more sensitive measurement.” The SQS is a quick but accurate self-reported assessment of sleep quality.

The SQS was validated based on two studies. Eligible patients in the 4-week, randomized, multicenter insomnia study were aged 30-75 years and were receiving a Food and Drug Administration–approved hypnotic agent as usual treatment for insomnia based on criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). The MQI was used daily for the duration of the study, wrote Ellen Snyder, PhD, of Merck & Co., in Kenilworth, N.J., and her coauthors.

The depression study was a randomized, double-blind, parallel-group, 12-month international trial evaluating the safety of the substance P antagonist aprepitant, compared with paroxetine hydrochloride. Patients were aged 18 years or older, with a DSM-IV diagnosis of major depressive disorder. Patients completed the SQS and PSQI at baseline, week 1, and week 8.

In insomnia patients, a Pearson correlation of –.76 was found at week 1 for the SQS in relation to the MQI.

In patients with depression, Goodman-Kruskal correlation coefficients for the SQS in relation to the Pittsburgh Sleep Quality Index (PSQI) were –.87, –.88, and –.92 at baseline, week 1, and week 8, respectively.

Correlations were negative because “better sleep quality is associated with a lower score on the MQI and PSQI, but a higher score on the SQS,” the authors noted.

The results support the use of the SQS as a “practical sleep measure that can effectively gauge sleep quality without significantly increasing the burden of clinical trial participants,” compared with lengthier assessments such as the MQI and PSQI, they added.

Funding for the study was provided by Merck Sharp & Dohme.

SOURCE: Snyder E et al. J Clin Sleep Med. 2018;14(11):1849-57.

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