The organ transplant symptom and well-being instrument - psychometric evaluation.

Abstract

Background:There is a need for instruments combining measurements of symptom distress and well-being in the organ transplant population.Objectives:The aim of this study was to describe the development and initial psychometric evaluation of a measure of symptoms and well-being in organ transplant recipients labelled the Organ Transplant Symptom and Well-being instrument (OTSWI) and to provide descriptive data on these matters.Method:In this cross sectional survey, the study sample (n=185) completed several measures including demographic information, the Short form- 36 items (SF-36), and the OTSWI to assess concurrent validity by exploring relationships between OTSWI and measures of health related quality of life (HRQOL). The expected scale dimensionality of the OTSWI questionnaire was examined both by the confirmatory multi-trait analysis program and by explorative principal component analysis (with oblique, varimax rotation). Scale reliability was further estimated using the Cronbach’s alpha.Results:There were eight factors built up from twenty of the initial fifty one items and were labelled fatigue, joint and muscle pain, cognitive functioning, basic activities in daily life, sleeping problems, mood, foot pain and economy. For the remaining twenty-one items no consistent and meaningful factors could be found leading to relevant symptoms acting as single items. All eight factors had satisfying internal convergent validity as well as good item-scale discriminatory validity or ‘success rate’.Discussion:Results support the internal consistency, reliability and concurrent validity of the OTSWI as an instrument to measure symptom distress and well-being in relation to organ transplantation. (Word count 244).