First assessment of a cost questionnaire for its agreement with administrative databases in females with stress urinary incontinence in Switzerland: a validation study

IntroductionEconomic research in the field of pelvic floor rehabilitation is lacking in transparency of methodology and consideration of indirect costs. Service use questionnaires collect cost data with the broad approach needed for the societal perspective of health economic studies. Nevertheless, these questionnaires are seldom validated. Therefore, this study aimed to evaluate the accuracy of a questionnaire to assess healthcare costs of females with stress urinary incontinence (SUI) in Switzerland. MethodsA questionnaire was developed to measure direct medical, direct non-medical and indirect costs in females with stress urinary incontinence living in the larger Bern area in Switzerland. Participants were recruited out of a prior study sample, where they had already completed the cost questionnaire. Administrative databases cost data were obtained for the investigation period. The agreement between the reported direct medical costs of the questionnaire with those from the providers billings was assessed using Pearson correlation coefficient (r), intraclass correlation coefficient (ICC) for agreement, Lins concordance correlation coefficient (LINCCC) and limits of agreement (LOA). ResultsFourteen participants were eligible for this study. Agreement between the two methods presented a Pearsons r of 0.64 [95%CI 0.16 to 1.00], ICC of 0.79 [95% CI 0.33 to 0.93] and LINCCC 0.75 [95% CI 0.19 to 0.86]. LOA results showed no evidence for systematically under- or overreporting. ConclusionsThe developed questionnaire seemed to be an acceptable representative for direct medical costs in females with stress urinary incontinence in Switzerland. However, direct non-medical and indirect costs were not compared to an external criterion.