What's known on the subject? and What does the study add?
Studies on erectile dysfunction (ED) therapies rely heavily on patient-reported outcomes (PROs) to measure efficacy on treatment response. A challenge when using PROs is interpretation of the clinical meaning of changes in scores. A responder analysis provides a threshold score to indicate whether a change in score qualifies a patient as a responder. However, a major consideration with responder analysis is the sometimes arbitrary nature of defining the threshold for a response. By contrast, cumulative response curves (CRCs) display patient response rates over a continuum of possible thresholds, thus eliminating problems with a rigid threshold definition, allowing for a variety of response thresholds to be examined simultaneously, and encompassing all data.
With respect to the psychosocial factors addressed in the Self-Esteem And Relationship questionnaire in ED, CRCs clearly, distinctly, and meaningfully highlighted the favourable profiles of responses to sildenafil compared with placebo. CRCs for PROs in urology can provide a clear, transparent and meaningful visual depiction of efficacy data that can supplement and complement other analyses.
- • To use cumulative response curves (CRCs) to enrich meaning and enhance interpretation of scores on the Self-Esteem And Relationship (SEAR) questionnaire with respect to treatment differences for men with erectile dysfunction (ED).
PATIENTS AND METHODS
- • This post hoc analysis used data from all patients who took at least one dose of study drug and had at least one post-baseline efficacy evaluation in a previously published 12-week, multicentre, randomized, double-blind, placebo-controlled trial of flexible-dose (25, 50, or 100 mg) sildenafil citrate (Viagra) in adult men with ED who had scored ≤ 75 out of 100 on the Self-Esteem subscale of the SEAR questionnaire.
- • CRCs were used on the numeric change in transformed SEAR scores from baseline to end-of-study for each SEAR component.
- • The horizontal axis of the CRC represented change from baseline on the SEAR score, and the vertical axis represented the percentage of patients experiencing that change or greater.
- • The differences between CRCs for the sildenafil group vs the placebo group were assessed using the Kolmogorov–Smirov test.
- • For each of the SEAR components, there was essentially no overlap in the CRCs between the sildenafil group (n= 113) and placebo group (n= 115 or 116, depending on the component), showing that a greater percentage of sildenafil recipients compared with placebo recipients had a more favourable change across the spectrum of response thresholds (P≤ 0.01).
- • Previous research showed that a 10-point score increase is the minimal clinically meaningful improvement for most SEAR components. In the sildenafil vs placebo groups, a ≥10-point score increase occurred in 72 vs 37% of patients, respectively, on the Sexual Relationship Satisfaction domain, 71 vs 41% on the Confidence domain, 76 vs 49% on the Self-Esteem subscale, 60 vs 44% on the Overall Relationship Satisfaction subscale, and 75 vs 38% on the Overall score.
- • With respect to the psychosocial factors addressed in the SEAR questionnaire, CRCs clearly, distinctly, and meaningfully highlighted the favourable profiles of responses to sildenafil compared with placebo.
- • CRCs for patient-reported outcomes in urology can provide a clear, transparent, and meaningful visual depiction of efficacy data that can supplement and complement other analyses.