Validation of the "Quality of Life in Life-Threatening Illness--Family Carer Version" (QOLLTI-F) in German-speaking carers of advanced cancer patients.

backgroundPalliative care is a multidisciplinary approach that focuses on the improvement of quality of life (QOL) of patients as well as their families. QOL research in palliative care has so far primarily focused on patients, but interest in the QOL of their relatives is increasing. For instruments measuring QOL in relatives, data on psychometric properties are often limited, and so far, none has been available in German.

objectiveThis study translates and validates the "Quality of Life in Life-Threatening Illness-Family Carer Version" (QOLLTI-F) in German-speaking carers of advanced cancer patients.

methodsThe QOLLTI-F was translated from English into German according to the World Health Organisation's recommendations and validated in informal caregivers of terminally ill cancer patients of three Viennese hospitals. Hope was measured to assess concurrent validity; traumatic stress, anxiety, depression and subjective burden were measured to assess discriminant validity. Internal consistency, test-retest reliability and discriminative power were established. The scale's factor structure was explored using a set of factor analyses.

resultsOf the 308 caregivers participating in the study, 42 completed the QOLLTI-F retest after a mean of 5 days. The internal consistency was α = 0.85 for the overall scale, Pearson correlation between test and retest lay at r = 0.92. As expected, a significant positive correlation was found with hope (r = 0.40) and significant negative correlations with traumatic stress (r = -0.41), depression (r = -0.51), anxiety (r = -0.52) and overall subjective burden (r = -0.55). The original seven-factor structure was not reproduced, but the scale showed a stable four-factor structure with factors capturing (1) feelings about carers' own life, (2) professional care, (3) interaction with the patient and others and (3) carers' outlook on life.

conclusionThis study provides a sound translation and validation of the first QOL assessment tool for caregivers of palliative care patients in German. It also adds to the knowledge on the scale's psychometric properties, which prove to be highly satisfactory. The QOLLTI-F may serve as an outcome measure in palliative care practice, clinical trials and epidemiological research.