Development of a multivariate prediction model for nocturia, based on urinary tract etiologies.

The main objective of our study was to determine which combination of modifiable and non-modifiable parameters that could discriminate patients with nocturia from those without nocturia. This will allow to study the etiology of nocturia and to estimate the treatment effect that address bladder capacity or nocturnal urine production on the number of nocturnal voids without need to uniform definitions for nocturnal polyuria or a reduced functional bladder capacity.

This was a post-hoc analysis of 3 prospective, observational studies conducted in Ghent University. Participants completed frequency volume chart (FVC) to compare characteristics between adults with and without nocturia. Study 1: adults with and without nocturia (n= 148). Study 2: patients ≥65 years with and without nocturnal LUTS (n= 54). Study 3: menopausal women before and after hormone replacement therapy (n= 43). All eligible patients (n= 183) completed a FVC during 24h (n= 13), 48h (n= 30), or 72h (n= 140). The combination of algorithms and number of determinants obtaining the best average area under the receiver operating curve (AUC-ROC) led to the final model. Differences between groups were assessed using the AUC-ROC and Mann- Whitney-Wilcoxon tests. Holm corrections were applied for multiple statistical testing. Also, the stability of the feature selection was evaluated.

The best discrimination was obtained when 13 determinants were included. However, a logistic regression model based on 7 determinants selected with random forest had comparable discrimination including an optimal signature stability. It was able to discriminate almost perfectly between nights with and without nocturia.

Relevant information to accomplish the excellent predictability of the model is; functional bladder capacity, 24 h urine output, nocturnal output, age, BMI. The multivariate model used in this analysis provides new insights into combination therapy as it allows simulating the effect of different available treatment modalities and its combinations This article is protected by copyright. All rights reserved.

International journal of clinical practice. 2018 Dec 16 [Epub ahead of print]

T K Olesen, M A Denys, A S Goessaert, E Bruneel, V Decalf, T Helleputte, J Paul, P Gramme, K Everaert

Universiteit Gent Faculteit Geneeskunde en Gezondheidswetenschappen, Department of Uro-gynaecology, St. Pietersnieuwstraat 33, Gent, 9000, Belgium.