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Use of the single‐item Patient Global Impression‐Severity scale as a self‐reported assessment of insomnia severity
Author(s) -
Snyder Ellen S.,
Tao Peining,
Svetnik Vladimir,
Lines Christopher,
Herring W. Joseph
Publication year - 2021
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/jsr.13141
Subject(s) - insomnia , clinical global impression , clinical trial , placebo , physical therapy , medicine , severity of illness , psychology , psychiatry , alternative medicine , pathology
We evaluated a single‐item Patient Global Impression‐Severity (PGI‐S) scale for assessing insomnia severity during the clinical development programme for suvorexant. The analyses used data from two randomised, double‐blind, placebo‐controlled, 3‐month, Phase III clinical trials of suvorexant in patients with Diagnostic and Statistical Manual of Mental Disorders IV criteria insomnia. Patients assessed insomnia severity during the previous week using the PGI‐S, a one‐item questionnaire containing six response options ranging from 0 (none) to 5 (very severe), at baseline and at Week 2, and Months 1, 2, and 3 after randomisation. The seven‐item Insomnia Severity Index (ISI) and other subjective and objective assessments were also completed by patients. PGI‐S responses were compared primarily with the ISI using descriptive statistics and correlations. The PGI‐S demonstrated favourable measurement characteristics (validity, reliability, responsiveness and sensitivity). PGI‐S scores decreased from baseline to Month 3 in a similar pattern to the ISI total score, and the Spearman correlation coefficient between PGI‐S and the ISI was .73. An improvement of ≥2 points on the PGI‐S defined a treatment responder, based on comparison to the ISI definition of a responder (improvement of ≥6 points). Our present findings suggest that the PGI‐S is a simple but valid, reliable, responsive, sensitive, and meaningful patient‐reported assessment of insomnia severity. The PGI‐S may be particularly useful as a companion outcome to sleep monitoring using wearable sleep devices or smartphones in at‐home settings.