Development and psychometric evaluation of the patient assessment of upper gastrointestinal symptom severity index (PAGI-SYM) in patients with upper gastrointestinal disorders

Objective: Describe the development and evaluation of a new self-report instrument, the patient assessment of upper gastrointestinal disorders-symptom severity index (PAGI-SYM) in subjects with gastroesophageal reflux disease (GERD), dyspepsia, or gastroparesis. Methods: Recruited subjects with GERD ( n = 810), dyspepsia ( n = 767), or gastroparesis ( n = 169) from the US, France, Germany, Italy, the Netherlands, and Poland. Subjects completed the PAGI-SYM, SF-36, a disease-specific HRQL measure (PAGI-QOL), and disability day questions. Two-week reproducibility was evaluated in 277 stable subjects. We evaluated construct validity by correlating subscale scores with SF-36, PAGI-QOL, disability days, and global symptom severity scores. Results: The final 20-item PAGI-SYM has six subscales: heartburn/regurgitation, fullness/early satiety, nausea/vomiting, bloating, upper abdominal pain, and lower abdominal pain. Internal consistency reliability was good (alpha = 0.79 - 0.91); test-retest reliability was acceptable (Intraclass correlation coefficients alpha = 0.60 - 0.82). PAGI-SYM subscale scores correlated significantly with SF-36 scores ( all p<0.0001), PAGI-QOL scores ( all p<0.0001), disability days ( p< 0.0001), and global symptom severity ( p< 0.0001). Mean PAGI-SYM scores varied significantly in groups defined by disability days ( all p< 0.0001), where greater symptom severity was associated with more disability days. Conclusions: Results suggest the PAGI-SYM, a brief symptom severity instrument, has good reliability and evidence supporting construct validity in subjects with GERD, dyspepsia, or gastroparesis.