Changes in uroflowmetry indicators with automatic interference elimination

Aim. The aim of this article is to compare the values of measured (Q MAX ) and calculated (Q MCLC ) maximal urine flow and the values of measured (T Q ) and calculated (T QCLC ) time to reach maximal flow in a large group of individual uroflowgrams during home uroflowmetry. Materials and Methods. We analysed 29,110 individual uroflowgrams from 719 patients with prostate adenoma, aged 50 to 73 years (mean age, 60.5 ± 8.2 years), collected between 2004 and 2024. Two algorithms were used: determination of Q MAX as the maximum value of the calculated flow (function extremum) and calculation of the actual value of the maximum flow after computer processing to eliminate interference and the WAG-effect (Q MCLC ). Results. The data showed the following differences between Q MAX and Q MCLC in the groups: 16.14 % for volumes up to 100 ml; 14.62 % for 100–200 ml; 13.75 % for 200–300 ml; 13.04 % for 300–400 ml; 14.25 % for 400–500 ml; 14.55 % for 500–600 ml; and 12.65 % for 600+ ml. For T Q and T QCLC values, the group differences were as follows: 3.49 % for volumes up to 100 mL; 2.27 % for 100–200 mL; 0.71 % for 200–300 mL; 0.97 % for 300–400 mL; 0.91 % for 400–500 mL; 3.51 % for 500–600 mL; and 1.51 % for 600+ mL. Conclusion. The study demonstrated a statistically significant difference between the maximum urine flow (Q MAX ) values obtained during measurement and the maximum urine flow value, after removing interference and the WAG effect (Q MCLS ) characteristic of any recorded volumes. Therefore, the accuracy of the data obtained may differ depending on the algorithm of uroflowgram processing. No statistically significant difference was found between T Q and T QCLC parameters. The algorithm of uroflowgrams processing used in the Sigma and Urovest uroflowmetry hardware and software system ensures high accuracy in determining maximum flow values; Urovest, in particular, has demonstrated reliability in this regard. The average determined difference between the Q MAX and Q MCLC values at different volumes of urination is 14.14 %.