Dumping syndrome following gastric bypass: validation of the dumping symptom rating scale.

There is a lack of prevalent data for dumping syndrome (DS) and methods discriminating between different symptoms of the DS. A self-assessment questionnaire, the Dumping Symptom Rating Scale (DSRS), was developed. The aim was to measure the severity and frequency of nine dumping symptoms and to evaluate the construct validity of the DSRS. Pre- and 1 and 2 years after Roux-en-Y gastric bypass surgery, 47 adults and 82 adolescents completed the DSRS. Cognitive interview was performed. Reliability and construct validity were tested. Effect sizes (ES) of changes were calculated. Patients found the questionnaire relevant. A high proportion of the respondents reported no symptoms affecting them negatively at all (floor effects). However, 12 % stated, quite severe, severe, or very severe problems regarding fatigue after meal and half of them were so tired that they needed to lie down. Nearly 7 % reported quite severe, severe, or very severe problems dominated by nausea and 6 % dominated by fainting esteem. The internal consistency reliability was adequate for both severity (0.81-0.86) and frequency (0.76-0.84) scales. ES were small, since some subjects experienced symptoms already preoperatively. Although most patients reported no or mild dumping symptoms 1 and 2 years after gastric bypass surgery, around 12 % had persistent symptoms, in particular, postprandial fatigue, and needed to lie down. Another 7 % had problems with nausea and 6 % had problems with fainting esteem. The DSRS is a reliable screening tool to identify these patients.