Gastric food residue frequently is observed on endoscopy despite fasting. To delineate factors promoting endoscopic food retention in the stomach. Two series of analyses were performed. Magnitudes of retained food in 834 patients from an endoscopy database were related to obstructive versus non-obstructive etiologies and gastric emptying findings. Emptying delays in 619 patients from a scintigraphy database were associated with endoscopic food retention, gastroparesis etiologies, and medications that modify gastric transit. On endoscopy, 310 (37 %) had large, 338 (41 %) showed medium, and 103 (12 %) exhibited small amounts of retained food in the stomach. Of 433 patients with definable etiologies of food retention, 106 (24 %) had obstructive causes. One hundred three of 327 (31 %) with non-obstructive conditions underwent scintigraphy showing mean 52 +/- 29 % 4-h retention. From the scintigraphy database, 164/619 patients (26 %) with delayed emptying exhibited food retention on endoscopy. Four-hour scintigraphic retention was greater with versus without retained food (41 +/- 25 vs. 32 +/- 22 %, P < 0.001). Retained food occurred more frequently with postsurgical (28/69, 41 %) versus diabetic (33/139, 24 %) and idiopathic (65/294, 22 %) gastroparesis (P = 0.006). Opiate use was more prevalent with increasing food retention (P = 0.02), while other medications that delay or accelerate emptying did not relate to retained food. Gastric food retention has obstructive and non-obstructive causes, and is found in one-quarter of gastroparesis, especially postsurgical cases. Gastric emptying delays correlate with amounts of retained food on endoscopy. Retention is influenced by opiates, but not other medications. These analyses delineate pathogenic factors promoting gastric food retention.
