Efficacy of drugs in chronic idiopathic constipation: a systematic review and network meta-analysis

There are several drugs available for the treatment of chronic idiopathic constipation, but their relative efficacy is unclear because there have been no head-to-head randomised controlled trials. We did a network meta-analysis to compare the efficacy of these therapies in patients with chronic idiopathic constipation.We searched Medline, Embase, Embase Classic, and the Cochrane Central Register of Controlled Trials for randomised controlled trials published from inception to week 3 June, 2019, to identify randomised controlled trials assessing the efficacy of drugs (osmotic or stimulant laxatives, elobixibat, linaclotide, lubiprostone, mizagliflozin, naronapride, plecanatide, prucalopride, tegaserod, tenapanor, or velusetrag) in adults with chronic idiopathic constipation. Participants had to be treated for a minimum of 4 weeks, and we extracted data for all endpoints preferentially at 4 weeks, 12 weeks, or both. Trials included in the analysis reported a dichotomous assessment of overall response to therapy (response or no response to therapy). We pooled the data using a random effects model, and reported efficacy and safety of all treatments as a pooled relative risk (RR) with 95% CIs to summarise the effect of each comparison tested. To rank treatments, we used P-scores, which measure the extent of certainty that a treatment is better than another treatment, averaged over all competing treatments.We identified 33 eligible randomised controlled trials of drugs, comprising 17 214 patients. Based on an endpoint of failure to achieve three or more complete spontaneous bowel movements (CSBMs) per week, the stimulant diphenyl methane laxatives bisacodyl and sodium picosulfate, at a dose of 10 mg once daily, were ranked first at 4 weeks (RR 0·55, 95% CI 0·48-0·63, P-score 0·99), and prucalopride 2 mg once daily ranked first at 12 weeks (0·82, 0·78-0·86, P-score 0·96). When response to therapy was defined as falilure to achieve an increase of one or more CSBM per week from baseline, diphenyl methane laxatives at a dose of 10 mg once daily ranked first at 4 weeks (0·44, 0·37-0·54, P-score 0·99), with prucalopride 4 mg once daily ranked first at 12 weeks (0·74, 0·66-0·83, P-score 0·79), although linaclotide 290 μg once daily and prucalopride 2 mg once daily had similar efficacy (P-scores of 0·76 and 0·71, respectively). Bisacodyl ranked last in terms of safety for total number of adverse events and abdominal pain (P-score 0·08).Almost all drugs studied were superior to placebo, according to either failure to achieve three or more CSBMs per week or or failure to achieve an increase of one or more CSBM per week over baseline. Although diphenyl methane laxatives ranked first at 4 weeks, patients with milder symptoms might have been included in these trials. Prucalopride ranked first at 12 weeks, and many of the included trials recruited patients who previously did not respond to laxatives, suggesting that this drug is likely to be the most efficacious for patients with chronic idiopathic constipation. However, because treatment duration in most trials was 4-12 weeks, the long-term relative efficacy of these drugs is unknown.None.