title: A 6 month, prospective, observational study of PDE5 inhibitor treatment persistence and adherence in Latin American men with erectile dysfunction.
abstract: OBJECTIVE
  To assess persistence/adherence rates of phosphodiesterase type-5 inhibitor (PDE5I) on-demand dosing in Latin American men with erectile dysfunction (ED), and explore patient characteristics and treatment factors that may be predictive for PDE5I persistence and adherence.
  
  
  METHODS
  Men from Brazil, Mexico, and Venezuela with ED who were naïve to PDE5Is were prescribed sildenafil, tadalafil, vardenafil, or lodenafil on-demand dosing and asked to provide information about PDE5I use at baseline and at 1, 3, and 6 months. Patients were persistent if they used ≥1 dose during the 4 week period prior to each evaluation. Patients were adherent if they complied with dosing instructions during most recent dose. Main outcome measures included Persistence and Adherence Questionnaire (PAQ), Partner Relationship Questionnaire (PRQ), Self-Esteem and Relationship (SEAR) Questionnaire, and International Index of Erectile Function (IIEF). Multivariate logistic regression was used to identify factors associated with persistence and adherence.
  
  
  RESULTS
  A total of 511 men were enrolled; most had mild to moderate ED (77.1%); 317 patients (62.0%) were prescribed tadalafil, 116 (22.7%) sildenafil, 75 (14.7%) vardenafil, and 3 (0.6%) lodenafil (not further analyzed). A total of 340 patients (66.5%) were 'persistent' at 6 months; 345 (67.5%) were 'adherent'. Persistence and adherence were associated with age, education level, and ED duration. Reasons for non-persistence included medication cost and lack of efficacy. Study limitations included its design, brief observation period, its bias observed toward tadalafil selection; its dependence on patient self-reporting, limited number of factors that were analyzed for persistence/adherence association, its small number of participating patients and Latin American countries, and inherent differences in PDE5I preference and medical practices.
  
  
  CONCLUSIONS
  Approximately two-thirds of PDE5I-naïve, Latin American men with ED were persistent and adherent after 6 months of therapy. Factors like education level, ED severity, and ED duration were associated with persistence and adherence; additional study is warranted to investigate the predictive value of these factors.
authors.affiliation: Asociación Mexicana para la Salud Sexual, AC (AMSSAC), Mexico City, Mexico.
authors.forename: Eusebio
authors.initials: E
authors.lastname: Rubio-Aurioles
authors.forename: Luis Antonio
authors.initials: LA
authors.lastname: Reyes
authors.forename: Leonardo
authors.initials: L
authors.lastname: Borregales
authors.forename: Carlos
authors.initials: C
authors.lastname: Cairoli
authors.forename: Sebastian
authors.initials: S
authors.lastname: Sorsaburu
mesh_terms: D002243:Carbolines / Q000627:therapeutic use; D002254:Carbonates / Q000627:therapeutic use; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D007093:Imidazoles / Q000627:therapeutic use; D007843:Latin America; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D058986:Phosphodiesterase 5 Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000627:therapeutic use; D011446:Prospective Studies; D011687:Purines / Q000627:therapeutic use; D011743:Pyrimidines / Q000627:therapeutic use; D012649:Self Concept; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use; D011795:Surveys and Questionnaires; D000068581:Tadalafil; D016896:Treatment Outcome; D014227:Triazines / Q000627:therapeutic use; D000069058:Vardenafil Dihydrochloride
chemical_list: D002243:Carbolines; D002254:Carbonates; D007093:Imidazoles; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D011743:Pyrimidines; D013450:Sulfones; D014227:Triazines; C532120:lodenafil carbonate; D000069058:Vardenafil Dihydrochloride; D000068581:Tadalafil; D000068677:Sildenafil Citrate