Validation of the Pelvic Organ Prolapse Quantification Index (POP-Q-I): a novel interpretation of the POP-Q system for optimization of POP research

Even though very precise at describing pelvic organ position, our criticism to the Pelvic Organ Prolapse Quantification (POP-Q) system is its limited ability to quantify the prolapse itself, since it still classifies prolapse into four stages, almost the same way as Baden and Walker (Clin Obstet Gynecol 15(4):1070-1072, 1972) did in 1972. As a result, the same grade can include a wide prolapse intensity range. The objective of this study was to assess inter-observer reliability in the Pelvic Organ Prolapse Quantification Index (POP-Q-I; Lemos et al., Int Urogynecol J 18(6):609-611, 2007) on a prospective randomized trial. Fifty consecutive women were prospectively examined by two members of the urogynecology staff, blinded to each other's results. Spearman's rank correlation was used to assess inter-observer reliability. Excellent correlation coefficients were observed, with an overall coefficient of 96.5% (CI: 0.889-1.042; p < 0.0001). The POP-Q-I is a method that makes POP research more efficient by directly measuring prolapse as a continuous variable, which is statistically more powerful than the categorical variables proposed by the POP-Q system. This study suggests that the POP-Q-I is applicable to clinical POP research.