Functional constipation in patients with hemorrhoids: a systematic review and meta-analysis

Hemorrhoids are common anorectal pathology, with high recurrence rates after surgical treatment. It is hypothesized that high straining forces during paradoxical contractions and inadequate relaxation are causally related to hemorrhoids. This review aimed to assess the coprevalence of functional constipation and dyssynergic defecation in a population with hemorrhoids. Moreover, the effects of rubber band ligation (RBL) were analyzed. Sources included Pubmed, Embase and CENTRAL . Randomized trials, cohort and case-control studies that investigated the prevalence of constipation in patients with hemorrhoids or the prevalence of hemorrhoids in patients with constipation compared to healthy subjects were included. Manometric studies were also eligible. Quality assessment was performed by using the Newcastle Ottawa Quality Assessment Scale. The primary outcome was the prevalence of functional constipation or dyssynergic defecation in patients with hemorrhoids. Nineteen studies were included. Prevalence of constipation was significantly higher in patients with hemorrhoids compared to controls [OR (odds ratio), 2.09; 95% CI (confidence interval), 1.27-3.44]. No significant difference in the prevalence of hemorrhoids between patients with constipation compared to controls was found (OR, 2.37; 95% CI, 0.67-8.44). Anal pressures in patients with hemorrhoids were significantly higher compared to healthy controls in all manometric studies. After RBL, these pressures remained significantly higher in patients with hemorrhoids ( P  = 0.001). Functional constipation, dyssynergic defecation and higher basal anal pressures are more prevalent in patients with hemorrhoids compared to controls. Improvement of therapy for functional constipation, especially dyssynergic defecation patterns, might lead to better long-term outcomes and reduce recurrence.