Association between Anticholinergic Burden and Constipation: A Systematic Review

The association between anticholinergic burden and constipation is not well defined and documented; for this reason, a systematic review was carried out in five databases (Medline, Embase, Cochrane Central Register of Controlled Trials, CINAHL, and Scopus), including studies assessing the correlation between anticholinergic burden, and constipation between January 2006 and December 2020. Data extraction was conducted independently by two researchers. Abstracts and titles were reviewed to determine eligibility for review with eligible articles read in full. From 2507 identified articles, 11 were selected for this review: six cross-sectional studies, four retrospective cohort studies, and a post hoc analysis of a randomized clinical trial. Overall, nine studies reported at least one statistical association between anticholinergic burden and constipation, finding 13 positive results out of 24 association measurements. A total of 211,921 patients were studied. The association between constipation and anticholinergic burden could be demonstrated in studies including 207,795 patients. Most studies were not designed to find differences in constipation prevalence and did not adjust the results by confounding factors. Our findings suggest that a correlation between anticholinergic burden and constipation exists. Higher quality-evidence studies are needed, including analysis that considers confounding factors, such as other non-pharmacological causes of constipation.