The reliability of the frequency-volume chart in assessing lower urinary tract symptoms

To assess the test-retest reliability of a 1-day frequency-volume chart (FVC) in men with lower urinary tract symptoms (LUTS).

Men with uncomplicated LUTS presenting to a urology clinic were asked to complete FVCs on three consecutive days. Standard measures of voiding frequency and volume were derived using International Continence Society definitions. Test-retest reliability of 1-day voiding behaviour was evaluated with an intraclass correlation coefficient (ICC). We also derived 95% confidence intervals (CI) for each measure, thereby indicating the precision of the measurements produced by a 1-day chart.

Of 140 patients with LUTS enrolled, 96 patients (69%) completed three 1-day FVCs. The frequency and volume measures typically had ICCs of 0.7-0.8; the "number of urgent voids" had the highest ICC. Nocturnal frequency and nocturnal volume were less reliable, with ICCs of 0.59 and 0.60, respectively. However, the 95% CIs around patient measurements tended to be wide. For 24-h voiding frequency, the true value for a patient might be up to +/- three voids away from the observed value for 95% of patients.

The measures of voiding behaviour derived from 1-day FVCs had sufficient test-retest reliability to differentiate between high and low levels of voiding symptoms. However, individual measurements could be imprecise, suggesting that, in men with LUTS, a 1-day FVC cannot be used for diagnosis, or monitoring changes in symptom scores after treatment.