Usefulness of ultrasonographic evaluation of stool and/or gas distribution for the treatment strategy of chronic constipation

Background and Aim This study aimed to evaluate the capability of ultrasonography to predict favorable outcomes of various medical therapies in patients with chronic constipation. Methods We enrolled 223 patients with chronic constipation (75 men, 148 women; mean age 62.9 ± 3.4 years). Transverse diameters of four segments of the colon (ascending [A], transverse [T], descending [D], sigmoid [S]), and the rectum [R]) were measured. The patients' stool and/or gas distribution was evaluated using the constipation index (CI) ([A + T + D + S + R]/5) and the left/right distribution ratio ([D + S]/[A + T]) according to our previous study. Patients were first treated with fiber‐ or osmosis‐based laxatives for 2 weeks. When constipation was not alleviated, stimulant‐based laxatives were added, and the patients were followed for another 2 weeks. Results Based on their clinical courses, patients were divided into four groups: nonresponders (group A) or responders (group B) to fiber‐ or osmosis‐based laxatives; nonresponders to any medical therapy (group C); and responders to stimulant‐based laxatives (group D). The CI was significantly higher in group A than group B ( P  < 0.05), with the receiver operating characteristic (ROC) curve analysis showing a CI cut‐off of 21.2 for predicting favorable outcomes of either fiber‐ or osmosis‐based laxatives ( P  < 0.05). Left/right distribution ratio was significantly lower in group C than group D ( P  < 0.05), and the ROC curve analysis showed a left/right cut‐off of 0.5 for predicting responders to stimulant‐based laxatives ( P  < 0.05). Conclusion These findings could help physicians predict favorable outcomes with laxatives without side effects for this patient population.