Reproducibility of high-resolution manometry among healthy and constipated persons

Background and Aims: Although high-resolution manometry (HR_ARM) is commonly used to diagnose defecatory disorders, its intraindividual day-to-day reproducibility is unknown. Since these measurements entail voluntary effort, this study aimed to evaluate the intraindividual day-to-day reproducibility of HR_ARM. Methods: In 22 healthy women (35 years [14] mean [SD]) and 53 constipated patients (42 years [13], 46 women), the rectal balloon expulsion time (BET), and anorectal pressures were measured with HR_ARM on 2 days separated by a median (interquartile range) of 15 days (11–53) in healthy and 40 days (8–75) in constipated patients. Anorectal pressures were evaluated at rest (20 s), during squeeze, and during evacuation. Rectal sensation was also evaluated in constipated patients. The agreement between both measurements was evaluated with Lin's concordance correlation coefficient (CCC) and other tests. Results: Among constipated patients, the anal resting (mean CCC [95%CI] 0.62 [0.43–0.76]) and squeeze pressures (CCC 0.65 [0.47–0.79]), rectoanal gradient during evacuation (CCC 0.42 [0.17–0.62]), and rectal sensory thresholds (CCC for urgency 0.72 [0.52–0.84]) were concordant. Between days 1 and 2, one or more outcomes, characterized as normal or abnormal, differed in 79% of constipated patients, i.e., anal resting and squeeze pressures, the gradient, and the rectal BET differed in, respectively, 25%, 19%, 36%, and 10% of constipated patients. The rectal BET was prolonged in three healthy persons (both days) and either on 1 day (six patients) or 2 days (33 patients) in constipated patients. Conclusions: While HR_ARM variables and the BET are reproducible within healthy and constipated persons, the outcome on repeat testing differed in 79% of constipated patients.