Is questionnaire enough to assess number of nocturic episodes? Prospective comparative study between data from questionnaire and frequency-volume charts.

OBJECTIVES To determine whether the voiding symptom questionnaire provides information regarding nocturia as accurate as that provided by frequency-volume (FV) charts, we evaluated patients with lower urinary tract symptoms. METHODS We prospectively analyzed 164 patients (62 men and 102 women, mean age 53.6 years, range 20 to 83) referred for the evaluation of lower urinary tract symptoms. At the initial visit, all patients answered the International Prostate Symptom Score (IPSS) questionnaire to quantify nocturia and subsequently were requested to complete a 3-day FV chart. RESULTS The differences in age between the men and women were not statistically significant. The total IPSS and IPSS bother scores were similar between the sexes. For all patients, the actual number of nightly voids in the FV charts and the IPSS nocturia score were modestly intercorrelated (r = 0.609, P <0.001). However, large individual differences were found in the nighttime diuresis rate (67.7%) between the IPSSs and FV charts. No statistically significant differences were found between men and women, but agreement was achieved in only 39.2% of patients younger than 60 years old and 22.4% of those 60 years old or older for the number of voids per night recorded by the FV charts and reported by the IPSS (P = 0.024). Overestimation of the number of nocturic episodes in the IPSS was more common than underestimation, especially in patients 60 years old or older (P = 0.014). CONCLUSIONS The findings of the present study revealed poor agreement between the subjectively estimated nocturnal frequency and chart-determined nocturnal frequency. Our results suggest that FV charts should be included as an integral part of evaluating nocturia in both sexes.