r.rafia@sheffield.ac.uk Exploratory psychometric analysis of the EQ-5D in a Myelofibrosis population Rachid Rafia, Clara Mukuria, ScHARR, University of Sheffield www.facebook.com/scharrsheffield School Of Health And Related Research INTRODUCTION The EQ-5D is a generic preference-based measure of health-related quality of life (HRQoL) applicable to a wide range of health conditions and treatments.1 Myelofibrosis (MF) is a rare but serious bone-marrow cancer in which the proliferation of an abnormal type of bone marrow stem cell results in fibrosis, or the replacement of the marrow with collagenous connective tissue fibres. Massive spleen enlargement is a consequence of the resulting extra-medullary haematopoiesis and can cause symptoms (typically abdominal pain, early satiety and difficulty in breathing); and can lead to complications such as portal hypertension, splenic infarction and vascular events. Patients commonly have symptoms such as fever, night sweats, and weight loss. There is no evidence about the appropriateness of the EQ-5D in MF; thus, this study aimed to provide psychometric evidence of its appropriateness. • This exploratory analysis suggests that the EQ-5D preference based and health dimensions had poor association with key symptoms in MF, except for the ‘pain/discomfort’ and ‘anxiety/depression’ health dimensions in some respect. • Although the EQ-5D captured some changes, these changes were much smaller than when assessed using the MF-SAF. • This exploratory analysis suggests that the EQ-5D measures’ ability to capture the effect of key symptoms in MF is limited to pain rather than the specific MF symptoms such as night sweat, itchiness. • However, results of this analysis need to be interpreted with caution due to the small number of patients and the potentially non-representative nature of the sample. METHODS The psychometric performance of the EQ-5D was assessed relative to that of a condition-specific measure, the modified MF Symptom Assessment Form (MF-SAF) version 2.0 using data from the ROBUST UK study. The ROBUST UK2 study collected data on both EQ-5D (5 levels) and modified MF-SAF v2.0 in a small sample of UK patients (n=48) with MF, post-polycythemia vera myelofibrosis (PPV-MF), or post-essential thrombocythemia myelofibrosis (PET-MF) with repeated measurement over 48 weeks (baseline, week 4, 12, 24 and 48 weeks). • The EQ-5D (5 levels) classification consists of five dimensions (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), each with five levels of response (no problems, slight problems, moderate problems, severe problems, and extreme problems). A single summary score is generated and range from 1 to -0.594 with 1 representing full health and 0 for dead. • The MF-SAF v2.03 has seven symptoms (abdominal discomfort, pain under left ribs, early satiety, night sweats, itching, bone or muscle pain and inactivity) each scored from 0 (absent) to 10 (worst imaginable). A total symptom score (TSS) is generated from the first 6 symptoms. In order for the EQ-5D to be appropriate, the measure should be associated with key symptoms in MF captured by the MF-SAF, at both baseline and over time. Analysis consisted of: • Convergent validity. Convergent validity was assessed by examining how well the EQ-5D preference-based measure and health state classification dimensions were associated with the MF-SAF total score and individual symptoms. Pearson’s correlations were used for continuous variables (e.g preference based and total clinical score); whilst spearman rank correlation was used for dimensions. Correlations were analysed using data at baseline only. The following cut-offs are used to determine the strength of the association: very strong >|0.6|, strong: <|0.6 to ≥ 0.5|, moderate: <|0.5 to ≥ 0.3| and weak:< |0.3|. Given the small sample size, further assessment of convergent validity was undertaken using data from all the time points. To account for repeated measures from t