title: Association between phosphodiesterase-5 inhibitors and nonarteritic anterior ischemic optic neuropathy.
abstract: BACKGROUND
  Use of phosphodiesterase-5 (PDE-5) inhibitors has been reported to be a risk factor for development of nonarteritic anterior ischemic optic neuropathy (NAION) in males, based largely on a number of case reports. The objective of our study was to determine whether men who use this class of medications are more likely than a matched control group to develop NAION.
  
  
  METHODS
  A pharmacoepidemiological nested case-control study was used to examine the above association in a health claims database of physician diagnoses and prescription medication dispensing. Cases of NAION were matched with corresponding controls and correlated with the use of PDE-5 inhibitors. A conditional logistic regression model was used to estimate rate ratios for development of NAION with use of PDE-5 inhibitors.
  
  
  RESULTS
  A total of 1,109 cases of NAION were found and matched to 1,237,290 controls identified within the database. Cases were more likely to have hyperlipidemia, diabetes, hypertension, myocardial infarction, and cerebrovascular accident in the year preceding their NAION. The adjusted rate ratio for any use of PDE-5 inhibitor in the year before the NAION was 1.01 (95% confidence interval [CI], 0.79-1.28); recent use of a PDE-5 inhibitor in the 30 days before the NAION also had no significant association, with an adjusted rate ratio of 0.96 (95% CI, 0.75-1.23). Results for individual PDE-5 inhibitors did not achieve statistical significance.
  
  
  CONCLUSIONS
  Our results do not suggest any association between having a prescription filled for PDE-5 inhibitor medication and receiving a diagnosis code for NAION. This is consistent with other studies in the literature that have failed to elucidate a plausible mechanism by which these drugs might compromise circulation at the optic nerve head.
authors.affiliation: Department of Ophthalmology and Visual Sciences (NAN, FSM), University of British Columbia, Vancouver, British Columbia, Canada; and Therapeutic Evaluation Unit (ME), Provincial Health Services Authority, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Nawaaz A
authors.initials: NA
authors.lastname: Nathoo
authors.forename: Mahyar
authors.initials: M
authors.lastname: Etminan
authors.forename: Frederick S
authors.initials: FS
authors.lastname: Mikelberg
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D015331:Cohort Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018917:Optic Neuropathy, Ischemic / Q000139:chemically induced* / Q000453:epidemiology*; D058986:Phosphodiesterase 5 Inhibitors / Q000009:adverse effects*; D016032:Randomized Controlled Trials as Topic; D012737:Sex Factors
chemical_list: D058986:Phosphodiesterase 5 Inhibitors