Calculating the direct costs of urinary incontinence: a new test instrument

Objectives To develop a universally applicable test instrument to measure t he total direct costs of urinary incontinence, including personal costs and treatment costs, i.e. the Dowell-Bryant Incontinence Cost Index (DBICI), a nd to study the construct validity and test-retest reliability of the instr ument, Patients and methods In a prospective observational study, 100 consecutive community-dwelling ambulatory women who presented with stress, urge or mixe d incontinence were asked to complete the DBICI questionnaire on two occasi ons, 7 days apart, before any treatment, The construct validity of the DBIC I was ascertained by correlation with other standard measures of urinary in continence severity; (i) a visual analogue scale (VAS) to assess the impact of leakage upon lifestyle. (ii) frequency-volume charts (voids/24 h, leaks /week): (iii) urine loss during a standard 1 h pad test: and (iv) two disea se- specific quality of life questionnaires. The test-retest reliability wa s measured by comparing the two test results and the construct validity of the individual subsets (personal and treatment) of the DBICI similarly asse ssed. Results Ninety-seven women completed the baseline assessment and 84 complet ed the re-test. The median (interquartile range) total direct incontinence cost (in Au$) was 12.89 (5.26-22.67) per week, which comprised the median p ersonal costs of 5.61 (1.68-10.36) and the median treatment costs of 4.96 ( 1.22-13.37). The total direct incontinence cost was significantly correlate d with the severity of urinary leakage on a 1 h pad test (Kendall's rank co rrelation, P = 0.01), with the VAS impact score (P < 0.001) and with the nu mber of leaks/week (P = 0.005). The correlation between the personal cost s ubset and other quantitative measures was also highly significant. Test-ret est analysis of the personal costs subset revealed that this subset was rob ust and satisfied the statistical criteria of repeatability, Conclusions The DBICI gives a detailed measure of the direct economic costs of urinary incontinence in ambulatory home-dwelling women, with the constr uct validity confirmed by the significant correlation with other quantitati ve measures of incontinence. By substituting local prices into the test for mat, the index should be useful in other countries. In the current climate of economic rationalization, such an index should be a part of future urina ry incontinence research.