Uroflowmetry (UF) and post-void residual urine (PVR) measurement are two important non-invasive tests used in the evaluation of patients with lower urinary tract symptoms (LUTS). It is known that in uroflowmetry, not only flow rates but also voiding patterns play an important role in differential diagnosis. In this study, we aimed to evaluate the relationship between voiding patterns in UF and PVR.

Demographic data, UF parameters, and PVR results of all patients presenting to our outpatient clinic with LUTS between 01.01.2022 and 01.08.2023 were retrospectively evaluated. Patients with missing data, UF voided volume less than 150 ml, and a history of neurological deficit were excluded from the study. Patients were divided into 5 groups based on voiding patterns: normal, intermittent, tower, staccato, plateau. Post-void residual urine volumes were measured using pelvic ultrasonography with the formula anteroposterior diameter × oblique diameter × transverse diameter × 0.52. Age, gender, voided volume, flow rate, and residual urine volumes were compared between patterns.

The mean age of the 120 patients included in the study was 53.02 +/- 13.3 years. Seventy-four patients (61.6%) were male, and forty-six (38.4%) were female. The median PVR value was calculated as 40 in the normal group, 50 in the intermittent group, 60 in the tower group, 92 in the staccato group, and 60 in the plateau group. There was no significant difference in voiding patterns concerning age, voided volume, and PVR results (p: 0.074, p: 0.167, p: 0.599). However, there was a significant difference in voiding patterns when compared with Qmax and gender (p: 0.000, p: 0.017) (Figure 1).

Uroflowmetry is non-invasive tool for evaluation of patients with lower urinary tract dysfunction. The pattern of the flow curve, maximum flow rate, voided volume are the important features of this study. No relationship was found between UF curves in children and PVR urine [1]. Evidence correlating parameters obtained in UF with PVR in adults similar to those in children has not been obtained [2]. In addition, studies have compared the voiding patterns and obtained PVR values between patients voiding with high voided volumes and those voiding with normal volumes using UF.  It has been shown that patients voiding with high volumes in UF have significantly higher PVR values and a higher rate of abnormal UF patterns [3].

Although no statistically significant difference was found in PVR comparisons between groups divided according to UF patterns, UF patterns are considered an important parameter in the diagnosis and follow-up of LUTS. Further studies with larger sample sizes and longer follow-up periods are needed in this regard.

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