Emerging links between non-neurogenic lower urinary tract symptoms secondary to benign prostatic obstruction, metabolic syndrome and its components: A systematic review

We carried out a systematic review in order to determine the connection between lower urinary tract symptoms secondary to bladder outlet obstruction and metabolic syndrome with its components. We searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, the Cochrane Database of Systematic Review and Web of Science from their inception until January 2015 to identify all eligible studies on the effect of metabolic syndrome (or component factors) on the presence or severity of lower urinary tract symptoms/bladder outlet obstruction in men. This analysis was carried out according to the STrengthening the Reporting of OBservational studies in Epidemiology guidelines. In total, 19 studies were identified as eligible for this systematic review. The quality assessment score was ≥50% in more than half of the studies (11/19). The evidence synthesis showed a positive association between metabolic syndrome, number of components and lower urinary tract symptoms/bladder outlet obstruction. In particular, the major endocrine aberrations of this connection are central obesity and hypertriglyceridemia. The links between insulin resistance and lower urinary tract symptoms/bladder outlet obstruction should be better investigated. Ethnic disparities in all examined studies showed a different impact of metabolic syndrome on lower urinary tract symptoms/bladder outlet obstruction severity and such influence still remain unclear. The relationship between metabolic syndrome and lower urinary tract symptoms/bladder outlet obstruction open the way for introducing physical activity and diet as recognized first-line interventions for treating lower urinary tract symptoms. However, this connection should be investigated in two different ethnic cohorts (i.e. Asian vs Caucasian) in order to better understand the impact of ethnic disparities on metabolic syndrome and lower urinary tract symptoms/bladder outlet obstruction severity.