The Larsson frequency/volume chart is not a substitute for cystometry in the investigation of women with urinary incontinence

The aim of the study was to assess the ability of the Larsson chart nomogram to predict the presence of detrusor instability or genuine stress incontinence without recourse to cystometry. The Larsson chart provides a probability of detrusor instability by plotting 24-hour urinary frequency against the range of void volumes. Frequency/volume chart data were obtained from the records of 216 patients who had undergone subtraction cystometry. The Larsson chart was assessed by comparing the probability of detrusor instability or of genuine stress incontinence obtained with the cystometric diagnosis. The maximum sensitivity of the Larsson chart was 52%, with a specificity of 70% for detrusor instability. For genuine stress incontinence these figures were 66% and 65% respectively. The Larsson chart provides no diagnostic information and does not remove the need for formal cystometric evaluation of patients with urinary incontinence.Editorial Comment: The authors critically assess the Larsson frequency/volume chart as a diagnostic aid in evaluating female incontinence, hoping to validate its use as a decisive test that could preclude the need for multichannel urodynamics. In a unselected cohort of females with incontinence the investigators compare the diagnosis made based on the Larsson chart to that arrived at by multichannel cystometrography. Although the Larsson chart is found to have low specificity and sensitivity in detecting DI or GSI, the voiding diary remains an important diagnostic aid in the evaluation of urinary incontinence, imparting much information regarding functional bladder capacity, urinary frequency, nocturia and daily fluid intake. This information is critical in understanding the overall function of the patient's lower urinary tract, suggests the presence of specific entities such as diabetes insipidus, contracted bladder, interstitial cystitis etc., and allows the physician to make simple adjustments in fluid intake that can minimize incontinence, nocturia and diuria. It is rather simplistic to believe that a voiding record alone could reliably distinguish between categories of incontinence, without any other evaluation.