External validation of Solomon-Greenwell nomogram for female bladder outlet obstruction

[Interobserver agreement in the diagnosis of bladder outlet obstruction in women]

Background

The diagnosis of bladder outlet obstruction (BOO) in women is a challenge for functional urology. In Mexico there are few data that report the prevalence of OTSV in women, being up to 24% in a group of patients.

Objective

The aim of this study is to compare six different definitions of bladder outlet obstruction and evaluate the interobserver agreement in an educational setting.

Material and Methods

Urodynamic studies (UDS) of women with and without diagnosis of BOO were retrospectively assesed. Farrar, Chassagne, Lemack, Defreitas, Blavais and Groutz, Solomon-Greenwell definitions were evaluated. All UDS were independently reviewed by 5 observers. The easiest, the hardest and the fastest were chosen. Interobserver agreement to classify the patients as obstructed was assessed by kappa reliability statistical analysis. We classified the type of mistakes the participants made; error of interpretation and miscalculation.

Results

A total of 28 urodynamic studies were reviewed. All observers had a substantial agreement (0.64-0.78) to classify BOO using all but Lemack and Solomon-Greenwell definitions. A total 120 errors from 840 responses were found; 45.8% errors of interpretation of UDS and 54.1% miscalculation of the equation. Finally, all the participants chose the Solomon-Greenwell was the most difficult definition.

Conclusion

Chassagne, Defreitas and Farrar definitions proved substantial interobserver agreement. Solomon-Greenwell and Lemack´s definitions had the highest number of pitfalls and the lowest level of agreement.