title: Patterns of switching phosphodiesterase type 5 inhibitors in the treatment of erectile dysfunction: results from the Erectile Dysfunction Observational Study.
abstract: OBJECTIVE
  This report describes patterns of treatment changes with the phosphodiesterase type 5 (PDE5) inhibitors tadalafil, sildenafil and vardenafil, and variables associated with those treatment changes, during the 6-month, prospective, pan-European Erectile Dysfunction Observational Study (EDOS).
  
  
  METHODS
  EDOS observed 8047 men > or = 18 years old with erectile dysfunction (ED), who began or changed ED therapy as part of their routine healthcare. Patients could change ED treatment at any time during EDOS. Data were collected at baseline and at 3 (+/- 1) and 6 (+/- 1) months. Analyses included ED treatment-naïve patients with complete follow-up who were prescribed a PDE5 inhibitor at baseline (n = 4026).
  
  
  RESULTS
  Most patients, regardless of what PDE5 inhibitor they were prescribed at baseline, continued on that same PDE5 inhibitor throughout the study. Continuation rates were approximately 89% in the tadalafil cohort, vs. 63-64% in the sildenafil and vardenafil cohorts. The variables most strongly associated with increased risk of switching were prescription of sildenafil or vardenafil, vs. tadalafil, at baseline (odds ratios 4.43 and 4.14 respectively; p < 0.0001). Of patients who switched from tadalafil to another treatment, nearly 25% had switched back to tadalafil by study end. In contrast, of patients who switched from sildenafil or vardenafil, < 10% from each cohort had switched back to their original treatment by study end.
  
  
  CONCLUSIONS
  The data suggest that tadalafil treatment in treatment-naïve ED patients may increase their likelihood of treatment continuation. These findings should be interpreted conservatively due to the observational nature of the study.
authors.affiliation: 2nd Department of Urology, Papageorgiou General Hospital and Center for Sexual and Reproductive Health, Aristotle University of Thessaloniki, Thessaloniki, Greece. hatzichr@med.auth.gr
authors.forename: D
authors.initials: D
authors.lastname: Hatzichristou
authors.forename: J M
authors.initials: JM
authors.lastname: Haro
authors.forename: A
authors.initials: A
authors.lastname: Martin-Morales
authors.forename: A
authors.initials: A
authors.lastname: von Keitz
authors.forename: A
authors.initials: A
authors.lastname: Riley
authors.forename: J
authors.initials: J
authors.lastname: Bertsch
authors.forename: M
authors.initials: M
authors.lastname: Belger
authors.forename: A M
authors.initials: AM
authors.lastname: Wolka
authors.forename: A
authors.initials: A
authors.lastname: Beardsworth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002243:Carbolines / Q000627:therapeutic use*; D015331:Cohort Studies; D007172:Erectile Dysfunction / Q000188:drug therapy*; D005500:Follow-Up Studies; D006801:Humans; D007093:Imidazoles / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D017060:Patient Satisfaction; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000627:therapeutic use*; D011446:Prospective Studies; D011687:Purines / Q000627:therapeutic use; D012044:Regression Analysis; D012720:Severity of Illness Index; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*; D011795:Surveys and Questionnaires; D000068581:Tadalafil; D013997:Time Factors; D016896:Treatment Outcome; D014227:Triazines / Q000627:therapeutic use; D000069058:Vardenafil Dihydrochloride
chemical_list: D002243:Carbolines; D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; D000068581:Tadalafil; D000068677:Sildenafil Citrate