Agreement between clinical methods of measurement of urinary frequency and functional bladder capacity

We assessed the agreement between 2 methods of data gathering of particular interest in urology: patient questionnaire and examination vs. frequency-volume charts. One hundred consecutive patients consulting our out-patient clinic were chosen for this study; 88 completed the study. Urinary frequency and bladder capacity were evaluated in each patient by using the above methods. The agreement between different methods of measurement was assessed by determining whether the 2 methods were interchangeable, a condition occurring if results of both methods fall within predetermined limits of variability. The results showed poor agreement between subjectively estimated urinary frequency and chart-determined urinary frequency. Moreover, different methods of measuring bladder capacity (endoscopic vs. chart) gave different results. Since chart-determined data are probably a more valid indication of urinary habits, we suggest that frequency-volume charts should be used more often in the investigation and follow-up of patients with micturition disorders.