Gastroparesis Cardinal Symptom Index (GCSI): Development and validation of a patient reported assessment of severity of gastroparesis symptoms

Abstract

Background Patient-rated symptom assessments are needed for evaluating the effectiveness of medical treatments and for monitoring outcomes in gastroparesis. Objective This paper summarizes the development and psychometric evaluation of a new instrument, the Gastroparesis Cardinal Symptom Index (GCSI), for assessing severity of symptoms associated with gastroparesis. Methods The GCSI was based on reviews of the medical literature, patient focus groups, and interviews with clinicians. A sample of 169 patients with a documented diagnosis of gastroparesis participated in the psychometric evaluation study. Patients completed the GCSI, the SF-36 Health Survey, and disability days questions at baseline and after 8 weeks. A randomly selected sub-sample of 30 subjects returned at 2 weeks to assess test retest reliability. Clinicians rated severity of symptoms, and both clinicians and patients rated change in gastroparesis-related symptoms over the 8 week study. Results The GCSI is based on three subscales: post-prandial fullness/early satiety (4 items); nausea/vomiting (3 items), and bloating (2 items). Internal consistency reliability was 0.84 for the GCSI total score and ranged from 0.83 to 0.85 for the subscale scores. Two week test retest reliability was 0.76 for the total score and ranged from 0.68 to 0.81 for subscale scores. Construct validity was supported, given that we observed significant relationships between clinician assessed symptom severity and GCSI total score, signif…