Validation of phone interview for follow-up in clinical trials on dyspepsia:: evaluation of the Glasgow Dyspepsia Severity Score and a Likert-scale symptoms test

Objective To validate two widely used dyspepsia scores performed by phone interview. Design Spanish translations of the Glasgow Dyspepsia Severity Score and a Likert-scale symptomatic test were evaluated. Responsiveness to the treatment, validity of the tests, and reproducibility of tests performed by phone interview were assessed. Setting Gastroenterology and endoscopy unit of a county hospital. Participants Group I consisted of 16 ulcer patients undergoing Helicobacter pylori eradication; Group II consisted of 29 healthy volunteers; and Group III consisted of 95 patients undergoing upper endoscopy. Measurements Glasgow Severity Dyspepsia Score and Likert test. Results Both tests showed adequate improvement (responsiveness) after H. pylori eradication. With regard to validity, the Glasgow and Likert test were significantly higher in 95 patients undergoing endoscopy than in 29 healthy controls. Analysis of reproducibility showed that intraobserver variation was low on both the Glasgow and Likert scores. No differences were found between consecutive tests regardless of whether both were performed by phone (24 patients) or one by phone and the other by clinical interview (40 patients). Interobserver variation analysis showed that the Glasgow test remained highly reproducible even when performed by different observers using different methods (clinical interview 8.83, phone 8.44, P = 0.12). By contrast, Likert-scale tests showed significant differences between observers for all symptoms except abdominal pain. Conclusions (1) The Glasgow score is highly reproducible even when performed by different observers and using different methods. (2) By contrast, Likert tests show greater variability. To be reproducible in different conditions, they need to be performed by the same observer. (C) 2000 Lippincott Williams & Wilkins.