Materials and methods
The study methods and primary results of the NOTABLe trial have been published [Eligible women 18 years of age or older with at least 3 months of ABL symptoms and a St. Mark’s score of 12 or greater were randomized 2:1 to either PTNS or sham treatment. A 4-week run-in was conducted to exclude those who reported symptom reduction below the inclusion threshold in response to completing bowel diaries and to self-imposed dietary and behavioral measures alone. Baseline measures included participant demographics, clinical characteristics, medical history and condition-specific ABL severity measures prior to run-in. Baseline quality of life measures were collected after run-in, prior to study-treatment initiation. Initial analyses for the primary study outcome of treatment response (i.e., treatment success) were performed using ≥4-point reduction from baseline in St. Mark’s score. Because published minimum important differences are reported to range from 3- to 5-point reductions in St. Mark’s score [Baseline demographic, clinical, and symptom characteristics were compared between treatment success and failure for each of the above definitions. Baseline symptom severity was established prior to the 4-week run-in and was defined as baseline St. Mark’s score for the primary treatment responder outcome, baseline patient global symptom control (PGSC) for the PGI-I outcome, and baseline average FIE per week for the FIE success outcome. Diet was assessed by measuring dietary and supplemental fiber intake as well as a 15-item meat/snack questionnaire that assesses intake of dietary fat (scores ranging from 0 to 60 with higher scores indicating greater dietary fat intake) [Descriptive statistics were used to evaluate success rates for each of the above subjective and objective definitions of success. Given differing rates of success by definition, factors associated with success for each definition were explored using bivariate analyses with Chi-squared tests, Student’s 