EVALUATION OF THE HOME PAD TEST IN THE INVESTIGATION OF FEMALE URINARY-INCONTINENCE

Objective To evaluate the use of the home pad test in the management o f patients with urinary dysfunction with reference to feasibility, nor mal data, reproducibility, compliance and accuracy when compared to vi deo urodynamics. Design A prospective study to determine 1. the accura cy of weighing pads by healthcare workers compared to weighing by pati ents with a spring balance; 2. the effects of evaporation; 3. the pad weight increase in continent women; 4. the compliance over 194 tests i n terms of acceptability and feasability; 5. the reproducibility in 11 2 women for the 24 h and 48 h tests, 6. the comparison with video urod ynamic studies in 149 patients. Setting A London teaching hospital. Ma in outcome measures Coefficient of variation and mean deviation analys is were employed to determine the accuracy of measurement. Percentage changes in standardised wet pad weights over a period of 8 weeks were used to determine the rate of weight loss due to evaporation. The perc entage of patients completing the test satisfactorily was documented. The increase in the weights of all the pads worn during the test perio d was measured in continent volunteers and incontinent patients. Video urodynamic diagnoses were used as the Gold Standard for comparison. R esults Twelve perineal pads were weighed by 15 healthcare workers with a resulting coefficient of variation equal to 1.55 % (standard error = 0.09 %). The mean deviation between patient-measured pad weights and staff-measured weights was 49 % (SD = 132 %). Pads wetted with saline showed no difference in weight after 1 week and less than 5 % change in weight after 8 weeks, with the upper 95 % confidence limit of less than 10 % loss. The mean pad weight increase over 48 h in continent wo men was 7.13 g (SD = 4.32 g) giving a 95 % upper confidence level of l ess than 15 g. Compliance was reasonably high with 161 (83 %) carrying out the test perfectly. Test-retest analysis of the 24 h and 48 h tes ts showed a strong relationship with correlation coefficients of 0.90 and 0.94 respectively. The reproducibility was also good, with differe nces as a percentage of the mean between the first and second test bei ng 6.9 % and 1.6 % for the 24 h and 48 h tests respectively. There was good concordance when the urodynamic study data was compared with pad weight data in terms of incontinence compared with no incontinence (k appa = 0.65), but a high false positive rate was detected for the pads . When eight of these patients with a false positive pad test had repe at video urodynamic studies, six were found to have detrusor instabili ty on the second study. Conclusions The home pad test combined with fr equency volume chart documentation is an easy test to perform. It is q uite robust and reasonably reproducible. This test should be added to complement the routine urodynamic tests and may have a role in detecti ng occult detrusor instability.