Coffee is more than just caffeine – a single-center, randomized, double-blinded, placebo-controlled superiority trial (CaCo trial)

Abstract

Abstract Objective Avoidance of prolonged postoperative bowel paralysis after colorectal surgery is of major importance due to its significant clinical implications. Postoperative caffeine consumption appears to be a promising strategy. The aim of this study was to assess whether postoperative oral caffeine intake shortens bowel hypomotility after elective laparoscopic colorectal surgery. Methods This was a single-center, randomized, double-blinded, placebo-controlled superiority trial conducted from October 1st, 2015 to August 10th, 2020. Patients aged >=18 years with malignant or benign disease undergoing elective laparoscopic colectomy were included and assigned randomly before surgery to receive 3x daily either 100 mg caffeine or 200 mg caffeine or 250 mg corn starch (placebo) after the procedure. Substances were served in indistinguishable capsules three times daily before the meals. The primary endpoint was time to first bowel movement, measured from the time of wound closure to the patient's first defecation. Secondary endpoints included colonic transit time, time to tolerance of solid food, length of hospital stay and perioperative morbidity. Results A total of 60 patients were randomized, 20 to each group. Twenty-seven patients followed the protocol and were included in the per-protocol (PP) analysis. Baseline characteristics were similarly distributed among the groups. In intention-to-treat analysis, the time to first bowel movement in the caffeine 200 mg group was 67.9 h (standard deviation [SD] 19.2), in the caffeine 100 mg group 68.2 h (SD 32.2) and in the placebo group 67.3 h (SD 22.7) (p=0.887). PP analysis and measurement of colonic transit time (41.8 h [SD 21.7] in the caffeine 200 mg group, 34.2 h [SD 22.9] in the caffeine 100 mg group and 46.3 h [SD 20.6] in the placebo group, p=0.317) confirmed non-significant differences. The time to tolerance of solid food, length of hospital stay and postoperative morbidity were comparable among the three groups and no deaths or related serious adverse events were observed during the study. Conclusion Although caffeine intake after laparoscopic colorectal surgery is safe, its administration was not associated with a shortened time to first bowel movement in contrast to previous studies. Thus, other ingredients of coffee might be responsible for the intestinal stimulatory effect previously described.