Measuring health-related quality of life in persons with genital herpes

Abstract

A disease-specific measure was needed for use in an international clinical trial to evaluate an investigational drug for genital herpes. A new measure was developed initially in the UK and translated and adapted for use in France, Italy, Germany, Denmark, Spain and the USA. This paper describes the translation and adaptation of the USA measure. It also describes the assessment of internal consistency, reproducibility, content validity, and construct validity (convergent and discriminant) of the measure. Two outcome measures of the final genital herpes-specific measure were developed: (1) a 21-item symptoms subscale; and (2) a 20-item HRQOL subscale. Each measure was scored and analyzed separately; the psychometric testing discussed in this paper refers to the HRQOL subscale only. The internal consistency of the HRQOL subscale is high (r = 0.93), as is the reproducibility measured with a two week interval (r = 0.85). Convergent validity is moderate to high. (Fleming Self-Regard subscale, r = 0.48; SF-36 Social Functioning dimension r = 0.59; SF-36 Mental Health dimension r = 0.50). The number of herpes outbreaks in the past year was a significant predictor of scores on the HRQOL subscale (0-1 outbreaks, mean = 82.1; 2+ outbreaks, mean = 72.1, p = 0.058) suggesting discriminant validity. The measure is currently in a phase III clinical trial including anti-viral therapy where the question of responsiveness can be addressed.