Psychometric evaluation of a visual analog scale for the assessment of anxiety

• Published in: Health and quality of life outcomes Vol. 8; no. 1; p. 57
• Main Authors: Williams, Valerie S L, Morlock, Robert J, Feltner, Douglas
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 08-06-2010; BioMed Central; BMC
• Subjects: Adult; Anxiety; Anxiety Disorders - diagnosis; Anxiety Disorders - drug therapy; Care and treatment; Diagnosis; Female; Health aspects; Humans; Lorazepam - therapeutic use; Male; Middle Aged; Paroxetine - therapeutic use; Psychological tests; Psychometrics; Randomized Controlled Trials as Topic; Reproducibility of Results; Time Factors; United States
• ISSN: 1477-7525; 1477-7525
• DOI: 10.1186/1477-7525-8-57

Fast-acting medications for the management of anxiety are important to patients and society. Measuring early onset, however, requires a sensitive and clinically responsive tool. This study evaluates the psychometric properties of a patient-reported Global Anxiety-Visual Analog Scale (GA-VAS).
Data from a double-blind, randomized, placebo-controlled study of lorazepam and paroxetine in patients with Generalized Anxiety Disorder were analyzed to assess the reliability, validity, responsiveness, and utility of the GA-VAS. The GA-VAS was completed at clinic visits and at home during the first week of treatment. Targeted psychometric analyses--test-retest reliabilities, validity correlations, responsiveness statistics, and minimum important differences--were conducted.
The GA-VAS correlates well with other anxiety measures, at Week 4, r=0.60 (p<0.0001) with the Hamilton Rating Scale for Anxiety and r=0.74 (p<0.0001) with the Hospital Anxiety and Depression Scale-Anxiety subscale. In terms of convergent and divergent validity, the GA-VAS correlated -0.54 (p<0.0001), -0.48 (p<0.0001), and -0.68 (p<0.0001) with the SF-36 Emotional Role, Social Function, and Mental Health subscales, respectively, but correlated much lower with the SF-36 physical functioning subscales. Preliminary minimum important difference estimates cluster between 10 and 15 mm.
The GA-VAS is capable of validly and effectively capturing a reduction in anxiety as quickly as 24 hours post-dose.