Nocturnal polyuria in men performing uroflowmetry for lower urinary tract symptoms

Purpose: To assess the prevalence of nocturnal polyuria (NP) in males performing uroflowmetry (UF) for lower urinary tract symptoms (LUTS), the impact of NP on UF outcomes, and bladder emptying, the association between NP and LUTS. Materials and methods: Men scheduled for UF were recruited in two Centres. Data collected were medical history, IPSS, UF, post-void residual urine volume (PVR), 3-day frequency-volume charts (FVC). The NP index was used to assess NP with a threshold of ≥ 33%. The relationship between NP and patient's aging was assessed. Results: 162 patients were included in the analysis. Mean age was 70.95 ± 8.04 years. The prevalence of NP was 54.9% (89/162). 110 (68%) patients reported nocturia, and among these, NP was documented in 76 (69%). Nocturia was found in 85% (76/89) of the population with NP. Total IPSS score, IPSS items #1, #2 and #7 showed a significant difference in men with NP compared with those without. Maximum flow rate and PVR did not significantly change comparing men with or without NP. Mean voiding volume (VV) of the night-time micturitions was significantly higher in men with NP compared to those without NP (532.1 ± 275.6 ml vs 175 ± 168.7 ml respectively, p < 0001), while mean VV day-time micturitions and mean VV at UF did not change between groups. Conclusions: NP had a high prevalence in men with LUTS performing UF. Aged males were more commonly affected by NP. Data demonstrated a strong relationship between NP and nocturia and increased urinary frequency while voiding symptoms were poorly related to NP.