title: Interactions between lower urinary tract symptoms and cardiovascular risk factors determine distinct patterns of erectile dysfunction: a latent class analysis.
abstract: OBJECTIVE
  An epidemiological association between lower urinary tract symptoms and erectile dysfunction is well established. However, interactions among multiple risk factors and the role of each in pathological mechanisms are not fully elucidated
  
  
  METHODS
  We enrolled 898 men undergoing prostate cancer screening for evaluation with the International Prostate Symptom Score (I-PSS) and simplified International Index of Erectile Function-5 (IIEF-5) questionnaires. Age, race, hypertension, diabetes, dyslipidemia, metabolic syndrome, cardiovascular disease, serum hormones and anthropometric parameters were also evaluated. Risk factors for erectile dysfunction were identified by logistic regression. The 333 men with at least mild to moderate erectile dysfunction (IIEF 16 or less) were included in a latent class model to identify relationships across erectile dysfunction risk factors.
  
  
  RESULTS
  Age, hypertension, diabetes, lower urinary tract symptoms and cardiovascular event were independent predictors of erectile dysfunction (p<0.05). We identified 3 latent classes of patients with erectile dysfunction (R2 entropy=0.82). Latent class 1 had younger men at low cardiovascular risk and a moderate/high prevalence of lower urinary tract symptoms. Latent class 2 had the oldest patients at moderate cardiovascular risk with an increased prevalence of lower urinary tract symptoms. Latent class 3 had men of intermediate age with the highest prevalence of cardiovascular risk factors and lower urinary tract symptoms. Erectile dysfunction severity and lower urinary tract symptoms increased from latent class 1 to 3.
  
  
  CONCLUSIONS
  Risk factor interactions determined different severities of lower urinary tract symptoms and erectile dysfunction. The effect of lower urinary tract symptoms and cardiovascular risk outweighed that of age. While in the youngest patients lower urinary tract symptoms acted as a single risk factor for erectile dysfunction, the contribution of vascular disease resulted in significantly more severe dysfunction. Applying a risk factor interaction model to prospective trials could reveal distinct classes of drug responses and help define optimal treatment strategies for specific groups.
authors.affiliation: Division of Urology, University of São Paulo Medical School, São Paulo, Brazil. Electronic address: jbrunhara@gmail.com.
authors.forename: João A B A
authors.initials: JA
authors.lastname: Barbosa
authors.forename: Eduardo
authors.initials: E
authors.lastname: Muracca
authors.forename: Élcio
authors.initials: É
authors.lastname: Nakano
authors.forename: Adriana R
authors.initials: AR
authors.lastname: Assalin
authors.forename: Paulo
authors.initials: P
authors.lastname: Cordeiro
authors.forename: Mario
authors.initials: M
authors.lastname: Paranhos
authors.forename: José
authors.initials: J
authors.lastname: Cury
authors.forename: Miguel
authors.initials: M
authors.lastname: Srougi
authors.forename: Alberto A
authors.initials: AA
authors.lastname: Antunes
mesh_terms: D002318:Cardiovascular Diseases / Q000150:complications*; D007172:Erectile Dysfunction / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D059411:Lower Urinary Tract Symptoms / Q000150:complications*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012720:Severity of Illness Index
keywords: AIC; Akaike information criterion; BIC; BMI; Bayesian information criterion; ED; LC; LCA; LCM; LUTS; NO; PDE5-I; WHR; age groups; body mass index; erectile dysfunction; latent class; latent class analysis; latent class model; lower urinary tract symptoms; nitric oxide; penis; phosphodiesterase 5 inhibitor; risk; waist-to-hip ratio