THE RESPONSIVENESS OF THE GLOBAL OVERALL SYMPTOM (GOS) SCORE - A 7-POINT LIKERT SCALE FOR THE MEASUREMENT OF DYSPEPSIA SYMPTOMS IN CLINICAL TRIALS

S Veldhuyzen van Zanten¹, N Chiba², D Armstrong², AN Barkun³, ABR Thomson⁴, V Mann⁵, S Escobedo⁵, P Sinclair⁶

¹Dalhousie University, Nova Scotia; ²McMaster University, Ontario; ³McGill University, Quebec; ⁴University of Alberta, Alberta; ⁵AstraZeneca Canada, Ontario; and ⁶INSINConsulting, Ontario

AIMS: To measure the responsiveness of a 7-point Likert scale (GOS) for the assessment of overall dyspepsia symptom severity.
METHODS: The GOS score was used in the CADET-HN trial, in which HP-negative uninvestigated dyspepsia patients (baseline GOS ³ 4) reported their GOS score after 1 month of treatment with omeprazole, ranitidine, cisapride or placebo. Patients were classified as responders (R) if their GOS was £ 2 or non-responders (NR) if GOS > 2. Patients were grouped according to their Overall Treatment Effect (a validated scale) scores: None (±1, 0), Small/Slight (± 2, ± 3), Moderate/Important (± 4, ± 5) and Large/Very (± 6, ± 7). To complete the responsiveness analysis the effect size (ES=DGOS/SD at baseline) and the standardized response mean (SRM=DGOS/SD of the change) were calculated.
RESULTS: Table presents the GOS (%) response for the Change and Importance rating after 1 month of treatment. A trend can be seen in the magnitude of the GOS in both ratings in line with the magnitude of the perception for all patients, R and NR. The ES (SD) was -1.07 (1.39) and SRM (SD) -2.10 (0.74) across all patients (n=491).
CONCLUSION: The GOS score demonstrates excellent responsiveness in the measurement of dyspepsia symptom severity.

Sponsored by AstraZeneca Canada Inc., Mississauga, Ontario.