Quality of Life (QoL) is the main goal of palliative care according to the definition of the World Health Organization. However, there is no consensus on how to define or assess QoL.
There are two conceptually different approaches to define QoL: the so-called ‘‘health-related’’ QoL, exemplified by measures such as the Sickness Impact Profile (SIP) and the Short Form-36 (SF-36), and the individual QoL, exemplified by the Schedule for the Evaluation of Individual QoL-Direct Weighting (SEIQoL-DW). The former questionnaires are heavily weighted towards functional status, thus confronting patients with terminal diseases with their progressive loss of function. Since they are based on a fixed, external, function-based value system, HRQoL questionnaires may not reflect the patients‘ individual perception of QoL accurately. Instruments such as the SEIQoL-DW allow the patients to name and rate, from their own perspective, the areas of life which they feel are most relevant to their overall QoL.
There is no gold standard to assess quality of life in palliative care. The choice of the instrument depends on the intention of the measurement. If the intervention is aimed at improving symptom control, disease and symptom specific tools should be used. If the overall impact of palliative care is the main outcome, and particularly when the focus is on psychosocial aspects, individual QoL instruments should be considered.