Hypothesized summative anal physiology score correlates but poorly predicts incontinence severity

To explore the relationship between such a construct and an existing continence score.

A retrospective study of incontinent patients who underwent anal physiology (AP) was performed. AP results and Cleveland Clinic Continence Scores (CCCS) were extracted. An anal physiology score (APS) was developed using maximum resting pressures (MRP), anal canal length (ACL), internal and external sphincter defects and pudendal terminal motor latency. Univariate associations between each variable, APS and CCCS were assessed. Multiple regression analyses were performed.

Of 508 (419 women) patients, 311 had both APS and CCCS measured. Average MRP was 51 mmHg (SD 23.2 mmHg) for men and 39 mmHg (19.2 mmHg) for women. Functional ACL was 1.7 cm for men and 0.7 cm for women. Univariate analyses demonstrated significant associations between CCCS and MRP (P = 0.0002), ACL (P = 0.0006) and pudendal neuropathy (P < 0.0001). The association between APS and CCCS was significant (P < 0.0001) but accounted for only 9.2% of the variability in CCCS. Multiple regression showed that the variables most useful in predicting CCCS were external sphincter defect, pudendal neuropathy and previous pelvic surgery, but only improving the scores predictive ability to 12.5%.

This study shows that the ability of AP tests to predict continence scores improves when considered collectively, but that a constructed summation model before and after multiple regression is poor at predicting the variability in continence scores.