The WHOQOL-BREF instrument: Psychometric evaluation of the Greek version in patients with advanced cancer and pain and associations with psychological distress.

Objectives: Assessment of the psychometric characteristics of the Greek version of the brief World Health Organization Quality of Life Instrument (WHOQOL-BREF) in patients with advanced cancer and pain, and exploration of the association between psychological distress and quality of life (QoL).

Method: The sample consisted of 145 patients with advanced cancer and pain who completed the WHOQOL-BREF, the Symptom Checklist-90 (SCL-90), and the Pain Visual Analogue Scale (VAS). In analysis, the following methods were used: Cronbach's alpha, Item Response Theory (IRT), polychoric, Pearson and polyserial correlation, t-test, and Linear regression.

Results: The internal consistency was high for all domains of the WHOQOL-BREF (Cronbach's α ≥ 0.731). Similarly, with the exception of three items, the WHOQOL-BREF items has large discrimination parameters suggesting that they have a high ability in differentiating subjects. On SCL-90, the three dimensions with the highest scores were Depression, Somatization, and Anxiety. The overall score for psychological distress, the Global Severity Index (GSI), showed significant negative association with all the WHOQOL-BREF factor scores (Physical Health: B = -1.488, p < 0.001, Psychological Health: B = -1.688, p < 0.001, Social Relationships: B = -0.910, p < 0.001, Environment: B = -1.064, p < 0.001). Male gender was associated with lower scores for Social Relationships (B = -0.358, p = 0.007) and Environment (B = -0.293, p = 0.026).

Significance of results: The Greek version of the WHOQOL-BREF showed good psychometric properties in patients with advanced cancer and can be used as a reliable instrument in clinical practice. The level of psychological distress can be considered a determinant of QoL in patients with advanced cancer and pain, independently of pain intensity or other clinical characteristics. In cancer, the disease process can activate multiple physiological and psychological mechanisms that lead to a wide range of symptoms of psychological distress. To improve their QoL, psychological intervention focused on the identification and alleviation of psychological distress in patients with advanced cancer, and help in finding meaning in their experience, should be provided.