Quantification of vaginal support: are continuous summary scores better than POPQ stage?

Abstract

This analysis compared 3 continuous variables as summary support loss (SL) scores with pelvic organ prolapse (POP) quantification (POPQ) ordinal stages. We used pooled baseline data from 1141 subjects in 3 randomized trials (CARE, n = 322; OPUS, n = 380; ATLAS, n = 439) to test 3 SL measures. The relative responsiveness was assessed using the standardized response mean of 2-year outcome data from the CARE trial. Each SL measure was strongly correlated with POPQ ordinal staging; the single most distal POPQ point had the strongest correlation. Improvements in anatomic support were weakly correlated with improvements in POP Distress Inventory (r = 0.17-0.24; P < .01 for each) but not with changes in POP Impact Questionnaire for all measures of SL or POPQ stage. While continuous, single number summary measures compared favorably to ordinal POPQ staging system, the single most distal POPQ point may be preferable to POPQ ordinal stages to summarize or compare group data.