Effect of Metabolic Syndrome on Anatomy and Function of the Lower Urinary Tract Assessed on MRI

Abstract

Objective: To investigate the relationship between metabolic syndrome (MetS) and lower urinary tract symptoms (LUTS) with functional and anatomic changes of the lower urinary tract with MRI.

Materials and methods: The bladder and prostate of 95 subjects (56M, 39F) were segmented on T2-weighted pelvic MRI using Materialize Mimics 3D software. Bladder wall volume (BWV), post-void residual (PVR) and prostate volume (PV) were quantified from the 3D renderings. LUTS were quantified using validated questionnaires administered at the time of MRI. Wilcoxin rank sum, win ratio and chi-square tests were used to correlate symptom scores, BWV, PVR and PV in patients 1) without vs with MetS, 2) with mild (IPSS or UDI-6: 0-7) vs moderate-severe (IPSS: 8-35 or UDI-6: ≥8) and 3) normal vs enlarged prostates (>40cm³). Multivariate linear regression was used to determine predictors for BWV, PVR and PV.

Results: Men with MetS had increased BWV (66.8 vs 51.1cm³, P = .003), higher PVR (69.1 vs 50.5cc, P= .05) and increased PV (67.2 vs 40.1cm³, P= .01). Women without and with MetS had similar BWV, PVR and LUTS (P= .3-.78). There was no difference in prevalence of MetS, BWV, PVR or PV in men or women with mild vs moderate-severe LUTS (P = .26-.97). Men with enlarged prostates were more likely to have MetS (P = .003). There was no difference in BWV, PVR and LUTS for men with normal vs enlarged prostates (P= .44-.94). In men, BWV was highly correlated with MetS (P = .005) on regression analysis.

Conclusion: MetS leads to detrusor hypertrophy and may contribute to impaired bladder function, likely related to the effect on the prostate.