The development of a quality of life instrument for osteoarthritis

Osteoarthritis (OA) is a common condition and a leading cause of pain and disability. The aim of this thesis was to explore issues associated with living with OA, develop an OA specific quality of life instrument and explore the physical and psychosocial factors that contribute to quality of life. A multiple methodological approach was used in this thesis. In the first study, analysis was undertaken of a large, community based survey to examine the prevalence and impact of joint problems on everyday activities. In the second study, in depth, semi-structured interviews were undertaken with 44 people with OA to explore the issues associated with living with OA. From these interviews, a disease specific, needs-based, quality of life instrument, the OAQoL, was developed and tested for appropriate psychometric properties. In the final study, the effect of physical and psychosocial influences on quality of life was explored. Structured equation modelling was used to construct a model explaining the relationship between pain, function, depression, anxiety, disease characteristics and demographics on quality of life. The key findings of this programme of work can be summarised as follows: (i) OA has an often considerable and complex impact on the individual; (ii) the OAQoL, a needsbased, disease specific outcome measure to assess of quality of has been derived from a strong conceptual framework and has rigorously tested for its psychometric properties; (iii) Anxiety and depression are high in people with OA and anxiety has a substantial influence on their perceived quality of life; (iv) co-morbidities are common in OA and are related to impairment of activities of daily living and quality of life; and (iv) while the location and number of painful joints in those with OA impacts on their ability to undertake the tasks of daily living, other aspects, such as anxiety, age and functional ability have a more substantial impact on quality of life.