Hypothesis / aims of study
To identify clinical and demographic characteristics associated with a clinically important treatment response in women randomized in a 2x2 factorial design to loperamide or placebo and to and anal exercises with biofeedback vs. educational pamphlet for treatment of fecal incontinence (FI).
Study design, materials and methods Data were analyzed from the Controlling Anal incontinence by Performing Anal Exercises with Biofeedback or Loperamide (CAPABLe) trial. In this analysis, treatment response was defined in two ways: as a clinically important improvement of -5 points in St. Mark’s scores, and as a ≥50% reduction in FI episodes, from baseline to 24 weeks. Multivariable logistic regression models included baseline characteristics and clinical variables significant at p≤0.2 on bivariate analysis, and treatment group. Treatment x predictor interactions were evaluated for one predictor at a time. Adjusted odds ratios (aOR) are presented with 95% confidence intervals (CI).
Results Overall, mean age was 63.8±11.1 years, 79.3% were White, mean BMI 29.8±7.0 and 85.3% were postmenopausal. Characteristics associated with treatment response on logistic regression analyses are presented in the table. Treatment response by St. Mark’s score was independently associated with being overweight (BMI 25 to 29.9) vs normal or underweight (BMI<25), no previous cesarean section (C/S), and higher baseline St. Mark’s score. When St. Mark’s score was assessed as a continuous variable, there was an estimated improvement at 24 weeks of -0.86 points in the St Mark’s score for each 1-point increase in baseline sphincter tone (95% CI -1.42, -0.30) and an improvement of -0.65 points in the St Mark’s score for each 1-point increase in baseline score (95% CI -0.80, -0.50). Being in the combined loperamide/biofeedback group vs control (placebo/educational pamphlet) group was independently associated with achieving a 50% reduction in FI episodes. Interpretation of results Certain clinical and demographic variables were associated with treatment response. Being overweight (compared to normal or underweight), history of C/S and increased clinical severity were associated with a minimally important clinical difference in the St Mark’s score. Receiving both active treatments was associated with a 50% reduction in FI episodes. Concluding message Overweight BMI, no history of C/S, severity of FI symptoms and combined active treatments were associated with treatment response in women randomized to loperamide vs. placebo, and biofeedback vs. education. This information may assist in counseling patients regarding the efficacy and expectations of conservative treatment modalities for women with FI.