Measuring Quality of Life among Older Adults. : Validation of the Norwegian WHOQOL-Old

Quality of life (QoL) assessment is an important aspect of nursing care. With increased older adult longevity, nurses are attending to lifestyles issues that accompany the QoL of both healthy and sick adults. Though the concept of QoL has been used for a long period of time, a consensus regarding a universal definition of QoL and a conceptual model is absent. There is also a lack of QoL measurements developed for and within the population of older adults. This has resulted in a new recently developed module for the assessment of QoL among older adults, which was part of an international study entitled “The Measurement of the Quality of Life in Older Adults and its Relationship to Healthy Ageing (WHOQoL-Old)”. The Norwegian WHOQoL-Old module (six facets, each with four items) has been developed as a part of this large cross-cultural project according to three phases; focus groups, a pilot study and a field study. A concrete definition of QoL has guided the WHOQoL-Group’s operationalization of the WHOQoL measurements; thus, the work has not been grounded in a theoretical or conceptual model. However, Wilson and Cleary have developed a conceptual model in which different types of variables, including QoL, interrelate. In this thesis, the definition and conceptual model support the validation of the WHOQoL-Old module. The specific aims of this thesis were as follows: 1. To explore whether there exists a consensus on the conceptualization and measurement of QoL among older adults (Paper I). 2. To explore content, convergence, known group and concurrent validity, as well as the psychometric properties of the final version of the WHOQoL-Old module (Paper II). 3. To investigate the fitness of the theoretical model in investigating the construct, known group and concurrent validity of the WHOQoL-Old module among healthy older adults (Paper III). 4. To investigate the fitness of the theoretical model in investigating the construct, known group and concurrent validity of the WHOQoL-Old module among sick older adults (Paper IV). Studies were performed using a literature review (N = 47; Paper I) and a crosssectional study (healthy N = 401, Sick N = 89; Paper II, III, IV). The questionnaires covered sociodemographic and self-reported health information, QoL, health and functional status scale, as well as depression. Results showed that a great majority of the reviewed studies lacked a conceptual model, one third of them lacked any formal definition of QoL, 34 different measurements were used and minimal empirical evidence was given for other psychometric properties (Paper I). In critically examining the basic structure of the measurement, the conceptual structure of the WHOQoL-Old module was supported, as correlation and multivariate analyses partly confirmed the relevance of individual items and factors in both the healthy and sick groups (Paper II). The results partially confirm the three aspects of construct validity: convergent validity, known-group validities and discriminate validity. Construct validity was supported by the confirmation of the theoretical-based hypothesis and research questions in Papers III and IV. Convergent validity (Paper II) was strengthened by showing that the most conceptually clear facets were Death and Dying for both groups, and Sensory Abilities in the sick group. The validation of known-groups was shown by different significant contributions in multiple regressions analysis for the two groups (healthy and sick; Paper II). This was evidenced by differences between healthy and sick older adults when testing conceptual models based on the WCM (Papers III and IV). Concurrent validity showed the WHOQoL-Old module total and facets to be significantly negatively correlated with the GDS–15 total score in both groups (Paper II). Overall, this thesis confirms the need for systematic validation of a measurement assessing QoL among older adults. It shows the strengths and weaknesses in the validity of the recently developed Norwegian WHOQoL-Old module measurement. The module needs further investigation, testing and refinement in various sociodemographic subgroups of Norwegians and older international adults. Moreover, this thesis contributes to knowledge concerning the QoL among older adults with or without community health care in Norway. This information can be used by nurses in the community to provide nursing care with important means to outline and apply interventions towards a good life, especially for vulnerable people.