The Validity of a New Structured Assessment of Gastrointestinal Symptoms Scale (SAGIS) for Evaluating Symptoms in the Clinical Setting

Dig Dis Sci. 2017 Aug;62(8):1913-1922. doi: 10.1007/s10620-017-4599-6. Epub 2017 May 27.


Background: The clinical assessments of patients with gastrointestinal symptoms can be time-consuming, and the symptoms captured during the consultation may be influenced by a variety of patient and non-patient factors. To facilitate standardized symptom assessment in the routine clinical setting, we developed the Structured Assessment of Gastrointestinal Symptom (SAGIS) instrument to precisely characterize symptoms in a routine clinical setting.

Aims: We aimed to validate SAGIS including its reliability, construct and discriminant validity, and utility in the clinical setting.

Methods: Development of the SAGIS consisted of initial interviews with patients referred for the diagnostic work-up of digestive symptoms and relevant complaints identified. The final instrument consisted of 22 items as well as questions on extra intestinal symptoms and was given to 1120 consecutive patients attending a gastroenterology clinic randomly split into derivation (n = 596) and validation datasets (n = 551). Discriminant validity along with test-retest reliability was assessed. The time taken to perform a clinical assessment with and without the SAGIS was recorded along with doctor satisfaction with this tool.

Results: Exploratory factor analysis conducted on the derivation sample suggested five symptom constructs labeled as abdominal pain/discomfort (seven items), gastroesophageal reflux disease/regurgitation symptoms (four items), nausea/vomiting (three items), diarrhea/incontinence (five items), and difficult defecation and constipation (2 items). Confirmatory factor analysis conducted on the validation sample supported the initially developed five-factor measurement model ([Formula: see text], p < 0.0001, χ 2/df = 4.6, CFI = 0.90, TLI = 0.88, RMSEA = 0.08). All symptom groups demonstrated differentiation between disease groups. The SAGIS was shown to be reliable over time and resulted in a 38% reduction of the time required for clinical assessment.

Conclusions: The SAGIS instrument has excellent psychometric properties and supports the clinical assessment of and symptom-based categorization of patients with a wide spectrum of gastrointestinal symptoms.

Keywords: Gastrointestinal symptoms; Irritable bowel syndrome; Quality of life; Questionnaire development; Validation.

Publication types

  • Validation Study

MeSH terms

  • Factor Analysis, Statistical
  • Female
  • Gastrointestinal Diseases / diagnosis*
  • Humans
  • Male
  • Middle Aged
  • Psychometrics
  • Reproducibility of Results
  • Surveys and Questionnaires / standards*
  • Symptom Assessment / methods*
  • Symptom Assessment / standards