Background/aims: Biofeedback therapy is widely used to treat patients with chronic constipation, especially those with dyssynergic defecation. Yet, the utility of high-resolution manometry with novel parameters in the prediction of biofeedback response has not been reported. Thus, we constructed a model for predicting biofeedback therapy responders by applying the concept of integrated pressurized volume in patients undergoing high-resolution anorectal manometry.
Methods: Seventy-one female patients (age: 48-68 years) with dyssynergic defecation who underwent initial high-resolution anorectal manometry and subsequent biofeedback therapy were enrolled. The manometry profiles were used to calculate the 3-dimensional integrated pressurized volumes by multiplying the distance, time, and amplitude during simulated evacuation. Partial least squares regression was performed to generate a predictive model for responders to biofeedback therapy by using the integrated pressurized volume parameters.
Results: Fifty-five (77.5%) patients responded to biofeedback therapy. The responders and non-responders did not show significant differences in the conventional manometric parameters. The partial least squares regression model used a linear combination of eight integrated pressurized volume parameters and generated an area under the curve of 0.84 (95% confidence interval: 0.76-0.95, P < 0.01), with 85.5% sensitivity and 62.1% specificity.
Conclusions: Integrated pressurized volume parameters were better than conventional parameters in predicting the responsiveness to biofeedback therapy, and the combination of these parameters and partial least squares regression was particularly promising. Integrated pressurized volume parameters can more effectively explain the physiology of the anorectal canal compared with conventional parameters.
Keywords: Biofeedback; Constipation; Least-squares analysis; Manometry.