High-resolution anorectal manometry profile in patients with chronic constipation versus control.

Background and aims: Studies comparing chronic constipation (CC) and asymptomatic subjects are lacking in our population. This study aimed to compare the high-resolution anorectal manometry (HRAM) profiles of patients with CC and healthy volunteers (HV), as well as patients with functional defecation disorders (FDD) and those without in the constipation group.

Methods: This retrospective comparative study included patients with CC who underwent HRAM and a balloon expulsion test (BET). As historical controls, healthy volunteers were recruited. If both ARM and BET were abnormal, FDD was diagnosed using ROME-IV criteria.

Results: Total 120 CC and 60 HV as controls were included. Maximum anal squeeze pressure (205 ± 62 vs. 170 ± 35 mmHg, p = 0.001), rectal sensations (1st sensation 49 vs. 40 ml, p = 0.024), desire to defecate (125 vs. 105 ml, p = 0.011) and maximum tolerable volume 171 vs. 150 ml, p = 0.018) were found to be significantly higher in CC patients as compared to controls. Median anal relaxation (15.5% [- 8.0 to 37.5] vs. 58.0% [34.0-77.0], p = 0.001), median defecation index (1.27 [0.88-1.74] vs. 2.00 [1.12-3.49], p = 0.001) and median recto-anal pressure gradient (17.50 [- 10.25 to 39.0] vs. 39.50 [7.50-69.0], p = 0.001) were significantly lower in CC patients. BET was not significant between CC and healthy volunteers (53% vs. 45%, p = 0.37). FDD was found in 57.5% of CC patients. Patients with FDD had higher anal residual pressure (95 ± 26 vs. 45 ± 21 mmHg, p = 0.001) and lower recto-anal pressure gradients than those without FDD (- 4.5 vs. 36 mmHg, p = 0.001). Rectal sensations were comparable in both FDD and non-FDD groups.

Conclusion: The clinical and manometric profiles of CC and HV patients differed significantly. FDD and rectal hyposensitivity were more common in those with CC. Type-1 recto-anal dyssynergia was the most common FDD sub-type.