Severity ranges of the International Prostate Symptom Score (IPSS); proposal to adjust the banding using baseline data of a large randomised trial in secondary care

Ito H1, Young G2, Lewis A2, Drake M1

Research Type

Clinical

Abstract Category

Male Lower Urinary Tract Symptoms (LUTS) / Voiding Dysfunction

Abstract 246
Male Incontinence
Scientific Podium Short Oral Session 13
Wednesday 29th August 2018
16:00 - 16:07
Hall C
Questionnaire Quality of Life (QoL) Benign Prostatic Hyperplasia (BPH) Male
1. North Bristol NHS Trust, Bristol Urological Institute, Level 3, Learning and Research Building, Southmead Hospital, Bristol, BS10 5NB UK, 2. Population Health Sciences, Bristol Medical School, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS UK
Presenter
H

Hiroki Ito

Links

Abstract

Hypothesis / aims of study
Ninety percent of men aged 50 to 80 years suffer from at least 1 lower urinary tract symptoms (LUTS) including storage symptoms, voiding symptoms and post-voiding symptoms. LUTS can compromise quality of life (QOL) and other social and sexual activities. Prevalence and severity increase with age and the progressive increase in the aged population group has emphasized the importance to our society of appropriate and effective management of male LUTS.
The International Prostate Symptom Score (IPSS), originally known as the American Urological Association symptom index for benign prostatic hyperplasia [1], is one of the most developed questionnaires to assess LUTS. Seven separate items are scored from 0 to 5, so the overall scale ranges from 0 to 35, where higher scores indicate more severe symptoms. To categorize patients’ symptoms and help physicians to manage treatment, the banding of symptom severity was set as 1-7 mild, 8-19 moderate, 20-35 severe. However, this banding was developed with generic groups involving LUTS and non-LUTS patients [1], and a previous study found men with voiding symptoms, storage symptoms and no symptoms to have average IPSS scores of 16.8, 14.6 and 8.5, respectively [2]. These figures implied that current banding might not be appropriate for grading LUTS patients by symptom severity.
To evaluate current banding of IPSS without any confounding of physician and institutional bias, clinical information from the Urodynamics for Prostate Surgery Trial; Randomised Evaluation of Assessment Methods (UPSTREAM), were used in the current study. UPSTREAM study is being conducted in major 26 multicentre United Kingdom (UK) to establish whether a care pathway not including invasive urodynamics is no worse than one in which it is included in men who are considering further treatment where surgery might be an option for BOO [3].
Study design, materials and methods
797 male patients seeking any treatment for their bothersome LUTS were recruited at urology departments of 26 hospitals in the UK. Recruitment was performed by research nurses and urologists in each centre and descriptive information, symptom assessment, flow rates and urinalysis were collected. Written informed consent was obtained from all enrolled patients.
This study extracted and analyzed the following baseline record including age, IPSS, IPSS-QOL score, urine flow rate measurement (maximum urinary flow rate (Qmax) and voided volume) and ultrasound estimate of post-void residual urine (PVR).
For statistical analysis, the Shapiro-Wilk test and normal Q-Q plot test were used to check the distribution and the normality of IPSS score in enrolled groups. To determine the cutoff point of IPSS for banding, the sensitivity and specificity levels derived from the receiver operating characteristic (ROC) curve plotted using scores of patients documenting worse IPSS-QOL scores were investigated. These were determined using 2 different cut-offs: firstly IPSS-QOL rated between “mixed” and “mostly dissatisfied”; secondly between “mostly dissatisfied” and “Unhappy”. A multivariate logistic regression model with backward selection was used to evaluate the relationships between IPSS-QOL and the IPSS and other subjective clinical factors. A stringent threshold was set for determining variable entry and removal from the multivariate analysis. IPSS was categorized by new banding and the other clinical factors were categorized by the median value. All data were analyzed using the SPSS software package (SPSS 24, Chicago, Illinois). All statistical tests were two-sided and were considered to be statistically significant for P < 0.05.
Results
The average age of 797 patients was 67.7 ± 9.2 years old. The normality test rejected the null hypothesis that IPSS was derived from a normally distributed population (P<0.001, Figure 1A). ROC curve showed 15 and 23 were the cut-off points as a predicter of patients QOL impact (for both the IPSS-QOL cut-off points chosen) (Figure 1B). The area under the receiver operating curve (AUROC) showed higher value in IPSS (0.725) than the other objective tests (for example, 0.465 in Qmax). Figure 1C showed the new banding (1-14 mild, 15-22 moderate, 23-35 severe) could divide LUTS male patients more consistently and reliably than the current banding (1-7 mild, 8-19 moderate, 20-35 severe). Multivariate analysis showed that new banding of IPSS is an independent predictor of patients QOL (P<0.001).
Interpretation of results
Normality test rejections indicated median or quartile value are not a suitable basis to derive banding of IPSS severity. ROC curve clearly indicated cutoff value of IPSS at 15 and 23 with higher AUROC than the other objective tests including uroflow. Multivariate analysis also showed independent and statistically significant relationship of the new banding of IPSS to assess QOL of male LUTS patients. Current banding thresholds, 8 and 20, showed no impact in these analysis.
Concluding message
This is the first study to validate a severity banding of IPSS scores using multicenter trial data, and proposes a new banding which reasonably divides male LUTS patients with statistically significant relationship to QOL.
Figure 1
References
  1. Barry MJ, Fowler FJ, Oleary MP, Bruskewitz RC, Holtgrewe HL, Mebust WK, Cockett ATK, Blaivas JG, Wein AJ. The American-Urological-Association Symptom Index for Benign Prostatic Hyperplasia. J Urol. 1992;148:1549–57.
  2. Liao CH, Chung SD, Kuo HC. Diagnostic value of International Prostate Symptom Score voiding-to-storage subscore ratio in male lower urinary tract symptoms. Int J Clin Pract. 2011;65:552–8.
  3. Bailey K, Abrams P, Blair PS, Chapple C, Glazener C, Horwood J, Lane JA, McGrath J, Noble S, Pickard R, et al. Urodynamics for Prostate Surgery Trial; Randomised Evaluation of Assessment Methods (UPSTREAM) for diagnosis and management of bladder outlet obstruction in men: study protocol for a randomised controlled trial. Trials. 2015;16:567.
Disclosures
Funding This project was funded by the National Institute for Health Research HTA programme (project number 12/140/01). This study was designed and delivered in collaboration with the Bristol Randomised Trials Collaboration (BRTC), a UKCRC Registered Clinical Trials Unit in receipt of National Institute for Health Research CTU support funding. Clinical Trial Yes Registration Number The National Institute for Health Research HTA programme (project number 12/140/01) RCT Yes Subjects Human Ethics Committee The study will be conducted in accordance with the recommendations for physicians involved in research on human subjects adopted by the 18th World Medical Assembly, Helsinki 1964 and later revisions. All 26 centres in UPSTREAM are approved by a centralised ethics committee (Oxford B Research Ethics Committee reference: 14/SC/0237). Helsinki Yes Informed Consent Yes