Development of a short form and scoring algorithm from the validated actionable bladder symptom screening tool

The majority of multiple sclerosis (MS) patients develop some form of lower urinary tract dysfunction, usually as a result of neurogenic detrusor overactivity (NDO). Patients identify urinary incontinence as one of the worst aspects of this disease. Despite the high prevalence of NDO, urological evaluation and treatment are significantly under-accessed in this population. The objectives of this study were: 1) to adapt the previously validated Actionable Bladder Symptom Screening Tool (ABSST) to a short form for ease and brevity of application in a clinical setting that is clinically meaningful; and 2) to develop a scoring algorithm that would be interpretable in terms of referring/considering precise diagnosis and treatment.

A US-based, non-randomized, multi-center, stand-alone observational study was conducted to assess the psychometric properties of the ABSST among patients who have MS with and without NDO. Mixed psychometric methods (e.g., classical statistics (Psychometric theory (3rd ed.). New York: McGraw-Hill; 1994) and item response methods (Applying the Rasch Model: Fundamental Measurement in the Human Sciences. New Jersey: Lawrence Earlbaum Associates; 2001)) were used to evaluate the predictive and clinical validity of the shortened form. The latter included clinicians flagging clinically meaningful items and associated response options which would indicate the need for further evaluation or treatment.

A total of 151 patients, all with MS and with and without NDO, were recruited by 28 clinicians in various US geographical locations. Approximately 41% of patients reported a history of or currently having urinary incontinence and/or urinary urgency. The prediction model across the entire range of classification thresholds was evaluated, plotting the true positive identification rate against the false positive rate (1-Specificity) for various cut scores. In this study, the cut-point or total score of greater than or equal to 6 had a sensitivity of approximately 85%, and specificity of approximately 93% (i.e., 85% patients would warrant being referred to a urologist and 93% of the patients whose symptoms would not warrant urologist referral).

Overall the short form ABSST demonstrated sensitivity and specificity as it maintained the integrity of the longer form tool. Concurrent validity for each subscale as well as predictive and concurrent validity of the total shortened instrument was demonstrated. This instrument provides a new method for assessing bladder problems among MS patients, and may facilitate earlier and more precise diagnosis, treatment, and/or referral to a specialist.