A rationale to change how we document pediatric uroflow studies:A Study from the SPU Voiding Dysfunction Task Force
Jason von Batavia, MD1, Hans Pohl, MD2, Walid Farhat, MD3, George Chiang, MD4, Hamid Hani Bani, MD5, Therese Collett-Gardere, PNP6, Israel Franco, MD6.
1childrens hospital of philadelphia, Philadelphia, PA, USA, 2Children’s National Hospital, Washington, DC, USA, 3University of Wisconsin, Madison, WI, USA, 4Rady Childrens Hospital, San Diego, CA, USA, 5Nemour’s Children Hospital, wilmington, DE, USA, 6Yale University, New Haven, CT, USA.
BACKGROUND: Uroflowmetry (uroflow) is a universal screening tool frequently used in pediatric urology (PU) practice for a variety of urological pathologies. Uroflow studies rely on careful clinical interpretation by a trained provider, but the inherent subjectivity involved in analyzing uroflow studies leads to limitations when comparing data across institutions or providers. METHODS: All members of the SPU Voiding dysfunction Task Force were invited to contribute deidentified uroflows to a centralized HIPPA complaint receiving database. All studies were then distributed to all raters and the individual studies were read by each rater. A separate database of studies was used by a senior and junior reader to evaluate the effect of mutual homogeneity in reading flows. Each observer’s findings were recorded according to ICCS criteria (ICCS), additional readings were done using a previously reported system which defined curves as smooth or fractionated (SF) and whether the shape resembled a bell, tower, or plateau (BPT). The uroflow parameters were included for these individual studies and the conglomerated data for each rater and the uroflow data were then used for analysis. Flow indexes (Qact/Qest)(FI) for Qmax and Qavg were generated using formulas previously reported for children 4-12 and for patients >=12 years, formulas were derived from recent data obtained from males and females found to be bell-shaped voiders with normal lag times and quiet pelvic floor on EMG. RESULTS: A total of 528 uroflow studies were available for review. Deidentified uroflow curves from all sites except one were read by multiple raters, while the that sites uroflows were read by 2 raters with a 20-year history of working together. Summary data for all uroflow studies are shown in Table 1. For uroflows that were read by multiple readers from 4 sites the Fleiss multirater kappa was calculated. Fleiss multirater kappa for 5 senior raters for the modified bell-plateau-tower curve system still ranged from fair to moderate (0.21 to 0.42) with the higher kappa value for plateau-shaped curve (0.42). The Fleiss multirater kappa for smooth and fractionated curves was 0.70 (for each), which were the two highest agreement scores obtained throughout the study.
CONCLUSIONS: Our analysis again substantiates our suspicions that flow curves read without well-defined criteria can’t be described with the ICCS criteria used today. Even adding been breaking curves into a shape and whether it is fractionated is not adequate and leads to too much variability amongst readers from different locations. We recommend the use of Qmax and Qavg FI and whether the shape is smooth or fractioned using this system markedly improves classification of uroflow curves. 
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