title: Adherence to 5-alpha reductase inhibitor therapy for benign prostatic hyperplasia: clinical and economic outcomes.
abstract: OBJECTIVE
  Our goal was to quantify relationships between adherence to 5-alpha reductase inhibitors (5-ARIs), the risk of acute urinary retention (AUR) and prostate surgery, and medical costs related to patients with benign prostatic hyperplasia (BPH).
  
  
  METHODS
  Claims recorded over a period of 6.5 years in a nationwide managed care database were analyzed. We conducted time-to-event multivariate analysis to evaluate relationships between adherence (medication possession ratio [MPR] thresholds of 70% or higher, 75% or higher, and 80% or higher), persistence (length of therapy), and the risk of AUR and surgery. We compared mean monthly BPH-related medical costs in patients with MPRs at or above thresholds and those with MPRs below thresholds and determined changes in BPH-related costs associated with 30-day increments of therapy.
  
  
  RESULTS
  In AUR analyses (N = 17,293), meeting or exceeding MPR thresholds was associated with a reduced likelihood of AUR for 70% (hazard ratio [HR], 0.380), 75% (HR, 0.613), and 80% (HR, 0.519) (P < 0.05 for all). In prostate surgery analyses (N = 17,739), the likelihood of surgery was reduced with MPR thresholds of 70% or above (HR, 0.294), 75% or above (HR, 0.542), and 80% or above (HR, 0.436) (P < 0.05 for all). A longer duration of therapy was associated with a reduced likelihood of AUR (HR, 0.860) and surgery (HR, 0.884) (P < 0.05 for both). In both populations, adherence and persistence were also associated with significantly decreased BPH-related medical costs.
  
  
  CONCLUSIONS
  In patients with BPH who received 5-ARI therapy, greater adherence and persistence were associated with significantly reduced risks of AUR and prostate surgery and with significantly lower medical costs. Maximizing adherence may enable patients to realize the potential long-term benefits of 5ARIs.
authors.forename: Stephen
authors.initials: S
authors.lastname: Gruschkus
authors.forename: Sara
authors.initials: S
authors.lastname: Poston
authors.forename: Michael
authors.initials: M
authors.lastname: Eaddy
authors.forename: Sham
authors.initials: S
authors.lastname: Chaudhari
keywords: 5-alpha reductase inhibitors; acute urinary retention; adherence; benign prostatic hyperplasia; pharmacoeconomics; prostate surgery