The Nottingham Health Profile as a measure of quality of life in zoster patients: convergent and discriminant validity

Abstract

The main symptoms of zoster, a disease caused by the reactivation of the varicella zoster virus (that causes chicken-pox) are: rash, associated with pain, burning, or itching, and pain that outlasts the rash sometimes by months or years. The uncomfortable and long-lasting symptoms of herpes zoster are likely to compromise the patient's quality of life. However, the impact of zoster on health-related quality of life has not previously been measured directly. Recent papers have demonstrated the ability of generic measures to discriminate among patients with different clinical symptoms. In this paper, we demonstrate the convergent validity for zoster of a generic measure, the Nottingham Health Profile (NHP), by measuring its correlation with rash progression, pain levels, and pain medications. The discriminant validity of the NHP was demonstrated by its ability to distinguish between different levels of pain severity. The NHP dimensions most highly correlated with the pain measures, were pain (0.42-0.50), energy (0.34-0.38) and sleep (0.32-0.38). The NHP scores in all six dimensions show large differences at different levels of pain severity that are statistically significant. These results demonstrate the NHP's validity as a measure of health-related quality of life in zoster patients