Further validation and responsiveness assessment of the herpes outbreak impact questionnaire and herpes symptom checklist

Abstract

Objective: The Herpes Outbreak Impact Questionnaire (HOIQ) and Herpes Symptom Checklist (HSC) are patient-completed questionnaires for assessing genital herpes outbreaks. This report describes the validation of paper-and-pencil versions of the scales and responsiveness assessments in an Australian clinical trial. Methods: Acceptability of the language of the original UK versions was tested with Australians. The HOIQ and HSC were then field-tested with patients. The new versions were validated using patients' daily responses to the questionnaires in a famciclovir study. Results: The HOIQ and HSC were readily adapted into Australian English and were acceptable to patients. Psychometric sample: N = 151; 81 (54%) male; mean age 39.9 ± 11.6 years; mean outbreaks 5.1 ± 3.0 per year. Internal consistency was good (alphas at outbreak 1 ranged 0.84-0.90 HOIQ and 0.73-0.87 HSC). Rasch analysis showed item stability over time. Correlations between HOIQ and HSC ranged from 0.46 to 0.60. Both scales distinguished outbreak healing presence or absence at day 6 (P = 0.001), and the HOIQ scale distinguished between symptom severity groups (P < 0.001). Scale scores declined significantly over study duration, exhibiting large effect sizes. Conclusions: The paper-and-pencil HOIQ and HSC were reliable, valid, and responsive in a clinical trial setting. These instruments are recommended for use in clinical studies. © 2008, International Society for Pharmacoeconomics and Outcomes Research (ISPOR).