A new validated score for detecting patient reported success on postoperative ICIQ SF: a novel two stage analysis from two large RCT cohorts
Introduction and hypothesisThe Patient Global Impression of Improvement (PGI I) and International Consultation of Incontinence Questionnaire Short Form (ICIQ SF) are validated instruments for the assessment of patient reported outcome measures (PROM) following treatment of stress urinary incontinence (SUI) However, there is a paucity of evidence as to what represents a successful postintervention ICIQ SF score. To determine the correlation between the postoperative ICIQ SF scores with the PGI I outcomes, the latter was considered one of the standard PROM following surgical treatment for SUI. The aim of this study was to determine, and if appropriate validate, an ICIQ SF cut off score that can predict a successful PROM as determined by PGI I.MethodsFour large datasets yielding 674 ICIQ SF score/PGI I outcome data pairs were used in this study for (a) determining and (b) validating the cut off ICIQ SF score for a successful PGI I outcome. Two long term follow up datasets were used representing follow up periods of 3 and 8 years of a randomized controlled trial (RCT) performed between April 2005 and April 2007 in a tertiary urogynaecology centre in Scotland, UK. All patients had urodynamic SUI or mixed urinary incontinence (MUI, with predominant SUI) and were randomized to treatment with either an inside out or an outside in transobturator tape (TVT O or TOT, respectively) as a sole procedure. The datasets yielded 432 ICIQ SF score/PGI I outcome data pairs. Successful outcome was defined as "very much improved/much improved" on the PGI I scale. SPSS v. 22.0 (IBM Corp. Armonk, NY) was used for all statistical analyses. The correlations and cut off scores generated were then validated on two independent datasets representing the 1 year and 4 year follow up periods of the multicentre RCT in six units in the UK. The datasets yielded 242 ICIQ SF score/PGI I outcome data pairs. All patients had urodynamic SUI or MUI (with predominant SUI) and were randomized to either adjustable single incision minisling (SIMS) or TVT O.ResultsSignificant correlations at the 0.01 level (two tailed) were clearly demonstrated between ICIQ SF scores at follow up and PGI I outcomes in terms of success/failure in both the generation and validation datasets. Higher ICIQ SF scores correlated with a 'poorer' PGI I score. Using ROC analysis, a postoperative ICIQ SF score of 6 was validated as approximately 90 sensitive and 85 specific for success/failure with a high Cohen's kappa coefficient of 0.83 (95 CI 0.74 0.89).ConclusionsThis two stage study provided a robust well validated postoperative ICIQ SF cut off score (of 6/21) that is likely to be associated with a patient reported successful outcome on the PGI I following surgical treatment with a midurethral sling in women at different stages of follow up over 1 8 years. Such a cut off score could enable the comparison of results between various studies and serve as a valuable guide for surgeons to counsel patients before and/or after surgical treatment. Our study fills a research gap in providing a way to compare trial results when baseline ICIQ SF scores are not available.
International Urogynecology Journal