The relationship between the Patient Generated Index (PGI) and measures of HR-QoL following diagnosis with head and neck cancer: are illness and treatment perceptions determinants of judgment-based outcomes?

ABSTRACT

OBJECTIVES: The primary objectives of this study were to examine the relationship between factors specified in the extended Self-Regulation Model (SRM) (illness and treatment perceptions and coping strategy) and three types of QoL outcome. Secondary objectives were to examine the relationships between outcome measures (general and cancer-specific HR-QoL and the Patient Generated Index (PGI)). DESIGN: Cross-sectional questionnaire study. METHODS: Eighty-two newly diagnosed patients with head and neck cancer (HNC) completed the Illness Perception Questionnaire--Revised (IPQ-R), the Beliefs about Medicines Questionnaire (BMQ), the Hospital Anxiety and Depression Scale (HADS), the Brief COPE and the Life Orientation Test (LOT-R). Patient outcomes were assessed using the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30, MOS Short Form Health Survey (SF-12v2) and the Patient Generated Index (PGI). RESULTS: These pre-treatment cross-sectional results have shown that key components of the SRM (beliefs and coping) were explanatory factors of HR-QoL outcomes. The PGI was not associated with any of the components of the SRM. The PGI was partially correlated with HR-QoL measures; in particular, Global QoL/health status (EORTC) and Mental Component Summary scores (SF-12). CONCLUSIONS: Our findings suggest that the illness perceptions approach may be a useful method for eliciting and understanding patients' beliefs regarding HNC. In order to maximize outcomes, simple interventions could address particular patient beliefs and coping styles.