Background: The aim of the study was to evaluate the impact of flavonoids on those symptoms important to patients with symptomatic haemorrhoids.
Methods: A comprehensive search strategy was used. All published and unpublished randomized controlled trials comparing any type of flavonoid to placebo or no therapy in patients with symptomatic haemorrhoids were included. Two reviewers independently screened studies for inclusion, retrieved all potentially relevant studies and extracted data.
Results: Fourteen eligible trials randomized 1514 patients. Studies were of moderate quality and showed variability in the results with potential publication bias. Meta-analyses using random-effects models suggested that flavonoids decrease the risk of not improving or persisting symptoms by 58 per cent (relative risk (RR) 0.42 (95 per cent confidence interval (c.i.) 0.28 to 0.61)) and showed an apparent reduction in the risk of bleeding (RR 0.33 (95 per cent c.i. 0.19 to 0.57)), persistent pain (RR 0.35 (95 per cent c.i. 0.18 to 0.69)), itching (RR 0.65 (95 per cent c.i. 0.44 to 0.97)) and recurrence (RR 0.53 (95 per cent c.i. 0.41 to 0.69)).
Conclusion: Limitations in methodological quality, heterogeneity and potential publication bias raise questions about the apparent beneficial effects of flavonoids in the treatment of haemorrhoids.