Objective assessment of urinary incontinence in women: comparison of the one-hour and 24-hour pad tests

OBJECTIVE: To compare the performance and clinical usefulness of the one-hour and 24-hour pad tests in terms of the relationship with reported symptoms and urodynamic diagnosis. METHODS: 341 women aged 40 years and over reporting lower urinary tract symptoms who were recruited to a nurse led continence service, and went on to receive urodynamics, a one-hour and a 24-hour pad test and completed a urinary diary. RESULTS: For both pad tests, there was a significant difference in the amount of urine leaked between the different urodynamic diagnoses (p<0.0001, for the one-hour and p=0.001 for the 24-hour test). Women with sphincter incompetence leaked significantly more than women with detrusor instability, or those with no abnormality. There was a significant difference between the proportion of women dry on a one-hour pad test and those dry on a 24-hour pad test (26.0% versus 38.4%, difference 12.4%; CI 5.5; 19.4). There is a positive relationship between amount of urine leakage and symptom severity expressed in terms of number of incontinent episodes for both pad tests. CONCLUSION: Both pad tests bore little relationship to the underlying urodynamic diagnosis but there was a positive relationship with symptom severity. The 24-hour pad test appears to be clinically a more useful too than the one-hour test. The two types of pad test are probably assessing incontinence in different ways. We suggest that the minimum data set should include structured questions, diaries and the 24-hour pad test.