Relationship between non-alcoholic fatty liver disease and benign prostatic hyperplasia/lower urinary tract symptoms: new insights from an Italian cross-sectional study

Purpose To investigate the prevalence of non-alcoholic fatty liver disease (NAFLD) assessed by the fatty liver index (FLI), in lower urinary tract symptoms (LUTS) patients and to estimate its ability in predicting LUTS. Methods We performed a cross-sectional analysis of 448 consecutive patients affected by LUTS. LUTS were evaluated using the IPSS questionnaire and metabolic syndrome (MetS) criteria (by International Diabetes Federation). FLI, prostate volume (PV), serum prostate-specific antigen, total testosterone (TT) and homeostasis model assessment (HOMA) index were evaluated. A value of FLI ≥40 was set to predict NAFLD. Patients were divided into Group A (FLI <40) and Group B (FLI ≥40). Odds ratios (OR) for having moderate–severe LUTS were calculated. Logistic regression model was fitted adjusting for confounding factors. Results Group B showed higher prevalence of MetS, IR, moderate–severe LUTS and ED, higher IPSS, IPSS-storage, IPSS-voiding, total prostate volume, insulin, HOMA and lower TT and IIEF-5. Univariate logistic regression analysis demonstrated that continuous FLI (OR = 1.03, p < 0.05) and FLI ≥40 (OR = 2.41, p < 0.01) significantly increase the risk of moderate–severe LUTS. Continuous FLI (OR = 1.12, p < 0.01) and FLI ≥40 (OR = 5.39, p < 0.01) were independent predictors of moderate–severe LUTS at the multivariate logistic regression analysis, after adjusting for confounding factors. Subjects with MetS and FLI ≥40 had 2.0-fold the risk of moderate–severe LUTS (OR = 2.10, p < 0.01). Conclusions Non-alcoholic fatty liver disease (NAFLD) subjects have higher risk of LUTS. The presence of FLI ≥40 can be used to predict subjects at high risk of LUTS.