The impact of hyoscine-N-butylbromide on adenoma detection during colonoscopy: meta-analysis of randomized, controlled studies

Background: Hyoscine-N-butylbromide (HBB) can induce flattening of colon folds through inhibition of smooth muscle activity, which improves mucosal visualization. Whether this affects polyp detection is controversial.

Objective: To evaluate whether HBB, administered during colonoscopy, improves polyp and adenoma detection.

Design: We performed a comprehensive search in MEDLINE and EMBASE databases to identify randomized, placebo-controlled trials (RCTs) in which HBB was administered during colonoscopy and which also reported the detection rate for polyps and/or adenomas (PDR and/or ADR, respectively).

Setting: Meta-analysis of 5 RCTs.

Patients: A total of 1998 patients (1006 receiving HBB) were included in the study.

Interventions: Intravenous administration of 20 mg (2 mL) HBB or 2 mL saline solution at the time of cecal intubation.

Main outcome measurements: The PDR was the primary outcome variable. Secondary outcomes included the ADR, the advanced adenoma detection rate (adv-ADR), and the mean number of polyps and adenomas per patient (PPP and APP, respectively).

Results: The PDR, ADR, and adv-ADR did not differ significantly between the 2 groups. The odds ratios (95% confidence interval [CI]) for PDR, ADR, and adv-ADR were 1.09, 95% CI, 0.91-1.31; 1.13, 95% CI, 0.92-1.38; and 0.9, 95% CI, 0.63-1.30, respectively. In addition, no significant differences were observed in PPP and APP between the 2 groups.

Limitations: Small number of studies included. Limited data about secondary outcomes and safety.

Conclusion: Our meta-analysis does not provide evidence that routine HBB administration at cecal intubation improves PDR or ADR. More studies are needed for final conclusions, particularly on HBB's effect on PPP and APP.