Hypothesis / aims of study
Bladder Diaries (BD) offer a non-invasive method for diagnostic assessment of patients with lower urinary tract symptoms (LUTS). Several samples of BDs are available in the literature, ranging in design, complexity and duration. Due to the lack of standardization and validity of the BDs, the International Consultation on Incontinence Questionnaire (ICIQ) suggested the development of a standardized tool validated through psychometric validation protocols (1). This was achieved by Bright et al. (2), who in 2014 published a study regarding the validation of the ICIQ Bladder diary (ICIQ-BD). This is a 3-day diary which measures the time and volume of fluid intake and urine output, as well as the use of pads/diapers, incontinence episodes and waking and sleeping times.
The use of the ICIQ-BD in non-English speaking population requires proper translation, as well as a series of validation tests, as stated by the authors of the original paper, since language differences may have an impact on the reliability of the tool. We report the translation and validation process of the ICIQ-BD to the Portuguese language. Portuguese is currently the 6th most spoken language in the world, with over 190 million native speakers around the globe, which clearly illustrates the importance of this study.
Study design, materials and methods
The translation of the ICIQ-BD was performed by a team of Portuguese Urologists with certified English knowledge, following permission by the ICIQ. A step of minor cross-cultural adaptations was performed, and the tool was subsequently back-translated by a non-medical professional English native-speaker, showing almost no differences when compared to the original. The Portuguese version of the ICIQ-BD was therefore accepted for further validation tests.
A total of 140 patients with LUTS under treatment at our urology department were recruited for this study. Each of them were asked to complete 1) the Portuguese version of the ICIQ-BD, 2) the Portuguese version of the International Consultation on Incontinence Questionnaire – Overactive Bladder – Short Form (OABq-SF), 3) the Evaluation of difficulty in filling of the BD questionnaire (non-validated questionnaire designed specifically for this study), 4) Demographic data questionnaire and 5) informed consent. After filling and delivering each of these materials, 30 patients were also recruited to fill, once again, the Portuguese version of the ICIQ-BD after 2-6 weeks, without any intervention aimed at treating LUTS in-between them, in order to study the test/retest reliability. Another group of 30 patients, which received some form of treatment for LUTS, filled a second Bladder diary 3-4 weeks after intervention, with the intention of testing the responsiveness of the diary. Patients under 18 years old, unable to fill the questionnaire or unable to give informed consent were excluded.
The sample size for the whole study, test-retest reliability and responsiveness was estimated in line with other questionnaire translation and validation studies.
Both translation and validation of this diary followed the ICIQ Validation Protocol, which encompasses primary and secondary tests. Primary tests (mandatory) include 1) Content validity, 2) Internal consistency and 3) Test-retest reliability. Secondary tests (optional) consist of 1) Construct validity, 2) Responsiveness and 3) Criterion validity.
Results
A total of 122 patients returned the Portuguese version of the BD (response rate of 87%). Participants had a mean age of 63.5 ± 15.1 years, with 73 (60%) males and 49 (40%) females. The education level of the subjects was as follows: 44% had up to 6 years of schooling, 30% 12 years (high school), and 26% higher education. The results of the analysis of the diaries are displayed in Table 1.
Content Validity – Patients filled a “Evaluation of difficulty in filling of the BD questionnaire” in order to assess content validity. The most common answer in all of the 6 items was 1 on a scale of 1-5, stating a very low difficulty in filling of this tool. The Bladder Sensation Scale was the item with the highest score, with 68% of patients answering 3, 4 or 5.
Internal Consistency – Cronbach’s alpha was calculated for the total 36 items of the 3-day BD, with a result of 0.78. The removal of neither of the 36 items resulted in a coefficient of <0.74 or >0.80.
Test-retest reliability – A high correlation was observed when comparing the two diaries for all measured items.
Construct validity – Three pre-defined and consensual hypothesis were tested in the studied population. 1) “Incontinence is more common in female patients than in males”, 2) “The prevalence of nocturia is higher in older patients, especially over 60 years old” and 3) “Incontinence is more common in patients aged over 60 years”. Data collected from the BD confirmed each of these hypotheses in the studied population
Criterion validity – 3 symptoms (urgency, nocturia and incontinence) were evaluated using the Overactive Bladder questionnaire short form. Urgency was reported in 46% of patients, nocturia in 67% and incontinence in 31%. A strong agreement was found between the reports of the BD and OABqSF, with 63%, 73% and 76% agreement for Urgency, Nocturia and Incontinence, respectively. Strong correlations were found for each of the studied parameters.
Responsiveness – Data from 26 patients who filled a second BD 3-4 weeks after intervention were analyzed. Only the total voided volume remained unchanged after the treatment, with all the other items showing a difference consistent with an intervention to treat LUTS, which, in this case, consisted of intravesical injection of Botulinum toxin.
Interpretation of results
As stated by the ICIQ group, proper validation of the Bladder Diary in each language is important prior to its use, since cultural differences and language obstacles often arise, compromising the obtained data. Translation of the ICIQ-BD to the Portuguese language was carried out in close contact with the ICIQ and expert opinions were also taken into consideration before developing the final version of the BD.
The Portuguese version of the ICIQ-BD performed successfully in all the primary and additional tests. Content validity was assured by both patients and experts, with the former clearly certifying the adequacy and content of this tool. Interestingly, when evaluating the difficulty of the Bladder Sensation Scale item, 68% of subjects answered 3 or higher in the Likert scale, clearly identifying this as the most troublesome parameter of the BD, a parameter which registered only a fair agreement on test-retest analysis in the original study.
The main limitation of our study is the inclusion of patients under treatment at a Universitary Hospital Urology Department. Although the participants had no previous knowledge of the ICIQ-BD, some could have been previously exposed to similar tools (such as frequency-volume charts or non-validated bladder diaries). The inclusion of patients from different settings such as primary healthcare units may be useful in the future to assure adequate validation for the general population.