Identifying possible biomarkers of lower urinary tract symptoms using metabolomics and partial least square regression.

INTRODUCTION: The objective of this study was to explore potential novel biomarkers for moderate to severe lower urinary tract symptoms (LUTS) using a metabolomics-based approach, and statistical methods with significant different features than previous reported. MATERIALS AND METHODS: The patients and the controls were selected to participate in the study according to inclusion/exclusion criteria (n = 82). We recorded the following variables: International prostatic symptom score (IPSS), prostate volume, comorbidities, PSA, height, weight, triglycerides, glycemia, HDL cholesterol, and blood pressure. The study of 41 plasma metabolites was done using the nuclear magnetic resonance spectroscopy technique. First, the correlations between the metabolites and the IPSS were done using Pearson. Second, significant biomarkers of LUTS from metabolites were further analysed using a multiple linear regression model. Finally, we validated the findings using partial least square regression (PLS). RESULTS: Small to moderate correlations were found between IPSS and methionine (-0.301), threonine (-0.320), lactic acid (0.294), pyruvic acid (0.207) and 2-aminobutyric-acid (0.229). The multiple linear regression model revealed that only threonine (p = 0.022) was significantly associated with IPSS, whereas methionine (p = 0.103), lactic acid (p = 0.093), pyruvic acid (p = 0.847) and 2-aminobutyric-acid (p = 0.244) lost their significance. However, all metabolites lost their significance in the PLS model. CONCLUSION: When using the robust PLS-regression method, none of the metabolites in our analysis had a significant association with lower urinary tract symptoms. This highlights the importance of using appropriate statistical methods when exploring new biomarkers in urology.

IPSS "bother question" score predicts health-related quality of life better than total IPSS score.

OBJECTIVE: The objective of this study was to investigate the role of bothersomeness of urinary symptoms on the general health-related quality of life (HRQoL) of patients with benign prostatic hyperplasia. We hypothesised that a higher International Prostate Symptom Score (IPSS) would be associated with a higher score on the IPSS bother question (IPSS-BQ), and a higher IPSS-BQ score would be the dominant factor associated with poorer general HRQoL. MATERIALS AND METHODS: A case-control, cross-sectional study design was used. Patients were selected according to strict inclusion and exclusion criteria and stratified by IPSS severity group (controls: IPSS < 8; moderately symptomatic: IPSS = 8-18; and severely symptomatic: IPSS > 18). The IPSS-BQ was used to analyse bothersomeness of urinary symptoms. A standardised, multidimensional measure of HRQoL (RAND-36) was used. Data were collected on prostate size, uroflowmetry parameters, prostate specific antigen and comorbidities that were quantified using the Charlson Index and the American Association of Anaesthesiologists (ASA) score. Multiple linear regression models were used to assess the impact of bothersomeness of urinary symptoms on physical and mental HRQoL. Cohen's d was used to determine the effect size. RESULTS: We included 83 patients in the statistical analysis. Linear regression analyses showed that the IPSS was not an independent predictor of HRQoL. Only the highest IPSS-BQ score was associated with both worse physical (P = 0.021) and mental (P = 0.011) HRQoL in the final model. The effect sizes were small to moderate. CONCLUSION: The IPSS-BQ score is an important predictor of HRQoL. The IPSS-BQ score as a proxy should be regarded as a standard outcome measure and reported in all LUTS-related research.

Predictors for surgical treatment in male patients with non-neurogenic lower urinary tract symptoms (LUTS).

OBJECTIVE: This study aimed to identify clinical and biochemical predictors for future surgical intervention in male LUTS patients. MATERIALS AND METHODS: In a prospective cohort study, parameters as International Prostate Symptom Score (IPSS) and IPSS "bother question" (IPSS-BQ), prostate volume (PV), maximal urine flow (Qmax), Prostate specific antigen (PSA), post-voidal residual urine (PVR) were assessed alongside comorbidities quantified using Charlson Comorbidity Index without age adjustment and American Society of Anesthesiology (ASA) score. For the statistical analysis, patients were categorized based on subsequent treatment approaches: Group 1: underwent surgery during follow-up; Group 2: received medical or no treatment. T-test was used to test differences between the groups. Logistic regression models were used to identify independent predictors of the need for future surgery. Following this analysis, we calculated the probability of requiring surgical intervention, with this likelihood being determined based on the accumulation of identified predictive factors. RESULTS: Of 63 patients, 22 underwent surgery over a median follow-up of 42 months. Significant baseline differences were observed in IPSS (p = 0.003), International Prostatic Symptom Score-Voiding subscore (IPSS-VS) (p = 0.002), IPSS-BQ (p = 0.001), Qmax (p = 0.007), and PVR (p = 0.02) between the groups. Higher IPSS-BQ, IPSS-VS, and lower Qmax are emerging as independent surgical treatment predictors in logistic regression analyses. CONCLUSION: The study identified IPSS-VS, IPSS-BQ, and Qmax as baseline predictors of future surgical intervention. A clear pattern of a gradual increase in the likelihood of requiring surgery was directly proportional to the cumulative number of these identified predictive factors.