Development and Validation of a Symptom Scale Specific for Ascites Accompanied with Cirrhosis: The ASI-7

OBJECTIVES: Ascites markedly affects the quality of life of patients with cirrhosis; however, there is currently no scale to measure the symptoms of ascites. We developed a scale to measure ascites-specific symptoms according to psychometric procedures. METHODS: A team consisting of specialists developed constructs representing the symptoms of ascites and question item pool. The constructs were verified in a qualitative study involving a small number of patients. The item pool was improved through a pilot study, and a prototype of the scale was prepared. To establish the scale and assess its properties, a questionnaire survey was conducted on 175 patients with ascites accompanied with cirrhosis. RESULTS: On the basis of the results of factor analysis and item response theory-based analyses, seven items, covering a wide range of severities and diverse symptoms, were selected to comprise the final scale (Ascites Symptom Inventory-7; ASI-7). The ASI-7 had a unidimensional factorial structure and high reliability (Cronbach's alpha coefficient of 0.96). The scale score was correlated with the degree of ascites evaluated by physicians, Short Form-36 (SF-36) physical functioning (PF), and SF-36 vitality (VT; P<0.001 each), indicating the criterion validity. The responsiveness after treatment was demonstrated by the mean standardized response of 1.18. Moreover, responses in the scale score were correlated with those in the degree of ascites, body weight, SF-36 PF, and SF-36 VT, respectively (P<0.001 each). CONCLUSIONS: An ascites-specific symptom scale was developed and its reliability, validity, and responsiveness were demonstrated. This simple scale may be used for the evaluation of ascites treatment and monitoring of treatment responses in patients with ascites.