Predictive modelling of 2-year potency outcomes using a novel 90-day erection fullness scale after robot-assisted...

To introduce a patient-reported erection fullness scale (%fullness) after robot-assisted radical prostatectomy (RARP) as a qualitative adjunct to the five-item version of the International Index of Erectile Function (IIEF-5) and as a 90-day predictor of 2-year potency outcomes.

Prospective data were collected from 540 men with preoperative IIEF-5 scores of 22-25 who underwent RARP by a single surgeon, and of whom 299 had complete data at all time points up to 2 years. In addition to standard assessment tools (IIEF-5 and erections sufficient for intercourse [ESI]), the men were asked to 'indicate the fullness you are able to achieve in erections compared to before surgery?' (range: 0-100%). The primary outcome was prediction of potency (defined as ESI) at 24 months, based on 90-day %fullness tertile (0-24%, 25-74% and 75-100%).

A total of 299 men with complete follow-up were included in the study. Significant predictors of 24-month potency included age, body mass index, pathological stage, nerve-sparing status and %fullness tertiles. When the men (preoperative IIEF-5 score 22-25) were assessed at 90 days after RARP, 181/299 (61%) had erections inadequate for intercourse. If IIEF-5 scores of 1-6 were used, 142/181 men (78%) would be targeted for early intervention. By contrast, if 0-24% fullness was used, 88/181 men (49%) would be targeted. If both the IIEF-5 score and %fullness were used, this would be reduced to 77/181 men (43%).

We introduce %fullness as a qualitative adjunct to the IIEF-5 score, and separately as a 90-day predictor of 2-year potency recovery. This initial report is hypothesis-generating, such that the use of %fullness enables the identification of men who are most likely to benefit from early, secondary intervention.