title: Cardiovascular drugs and erectile dysfunction - a symmetry analysis.
abstract: OBJECTIVE
  Erectile dysfunction is a common problem among patients with cardiovascular diseases and the influence of cardiovascular drugs is much debated. The aim of this study was to evaluate the short term potential for different cardiovascular drugs to affect the risk of being prescribed a drug against erectile dysfunction.
  
  
  METHODS
  We employed a symmetry analysis design and included all Danish male individuals born before 1950 who filled their first ever prescription for a cardiovascular drug and a 5-phosphodiesterase inhibitor within a 6 month interval during 2002-2012. If the cardiovascular drug induces erectile dysfunction, this would manifest as a non-symmetrical distribution of subjects being prescribed the cardiovascular drug first vs. persons following the opposite pattern. Furthermore, we calculated the number of patients needed to treat for one additional patient to be treated for erectile dysfunction (NNTH).
  
  
  RESULTS
  We identified 20 072 males with a median age of 64 years (IQR 60-70) who initiated a cardiovascular drug and a 5-phosphodiesterase inhibitor within a 6 month interval. Sequence ratios showed minor asymmetry in prescription orders after adjustment for trends in prescribing. This asymmetry was most profound for thiazides (1.28, 95% CI 1.20, 1.38), calcium channel blockers (1.29, 95% CI 1.21, 1.38) and ACE inhibitors (1.29, 95% CI 1.21, 1.37), suggesting a small liability of these drugs to provoke erectile dysfunction. NNTH values were generally large, in the range of 330-6400, corresponding to small absolute effects.
  
  
  CONCLUSIONS
  Our study does not suggest that cardiovascular drugs strongly affect the risk of being prescribed a drug against erectile dysfunction on a short term basis.
authors.affiliation: Clinical Pharmacology, Department of Public Health, University of Southern Denmark, DK-5000, Odense C, Denmark.
authors.forename: Lotte
authors.initials: L
authors.lastname: Rasmussen
authors.affiliation: Clinical Pharmacology, Department of Public Health, University of Southern Denmark, DK-5000, Odense C, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Hallas
authors.affiliation: Clinical Pharmacology, Department of Public Health, University of Southern Denmark, DK-5000, Odense C, Denmark.
authors.forename: Kenneth Grønkjaer
authors.initials: KG
authors.lastname: Madsen
authors.affiliation: Clinical Pharmacology, Department of Public Health, University of Southern Denmark, DK-5000, Odense C, Denmark.
authors.forename: Anton
authors.initials: A
authors.lastname: Pottegård
mesh_terms: D000368:Aged; D002317:Cardiovascular Agents / Q000009:adverse effects*; D007172:Erectile Dysfunction / Q000139:chemically induced / Q000188:drug therapy / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use; D012307:Risk Factors
chemical_list: D002317:Cardiovascular Agents; D010726:Phosphodiesterase Inhibitors
keywords: cardiovascular agents; drug-related side effects and adverse reactions; erectile dysfunction; pharmacoepidemiology; phosphodiesterase inhibitors; symmetry analysis