title: Testosterone lab testing and initiation in the United Kingdom and the United States, 2000 to 2011.
abstract: BACKGROUND
  New formulations, increased marketing, and wider recognition of declining testosterone levels in older age may have contributed to wider testosterone testing and supplementation in many countries.
  
  
  OBJECTIVE
  Our objective was to describe testosterone testing and testosterone treatment in men in the United Kingdom and United States.
  
  
  METHODS
  This was a retrospective incident user cohort.
  
  
  METHODS
  We evaluated commercial and Medicare insurance claims from the United States and general practitioner healthcare records from the United Kingdom for the years 2000 through 2011.
  
  
  METHODS
  We identified 410,019 US men and 6858 UK men who initiated a testosterone formulation as well as 1,114,329 US men and 66,140 UK men with a new testosterone laboratory measurement.
  
  
  METHODS
  Outcome measures included initiation of any injected testosterone, implanted testosterone pellets, or prescribed transdermal or oral testosterone formulation.
  
  
  RESULTS
  Testosterone testing and supplementation have increased pronouncedly in the United States. Increased testing in the United Kingdom has identified more men with low levels, yet US testing has increased among men with normal levels. Men in the United States tend to initiate at normal levels more often than in the United Kingdom, and many men initiate testosterone without recent testing. Gels have become the most common initial treatment in both countries.
  
  
  CONCLUSIONS
  Testosterone testing and use has increased over the past decade, particularly in the United States, with dramatic shifts from injections to gels. Substantial use is seen in men without recent testing and in US men with normal levels. Given widening use despite safety and efficacy questions, prescribers must consider the medical necessity of testosterone before initiation.
authors.affiliation: Department of Epidemiology (J.B.L., T.S., M.A.B.), Sheps Center for Health Services Research (D.L., M.A.B.), and Department of Medicine (J.L.S.), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599; Department of Pharmaceutical Sciences (C.R.M.), University of Basel, 4003 Basel, Switzerland; and Department of Epidemiology (S.S.J.), Boston University, Boston, Massachusetts 02118.
authors.forename: J Bradley
authors.initials: JB
authors.lastname: Layton
authors.forename: Dongmei
authors.initials: D
authors.lastname: Li
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Meier
authors.forename: Julie L
authors.initials: JL
authors.lastname: Sharpless
authors.forename: Til
authors.initials: T
authors.lastname: Stürmer
authors.forename: Susan S
authors.initials: SS
authors.lastname: Jick
authors.forename: M Alan
authors.initials: MA
authors.lastname: Brookhart
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017723:Drug Utilization Review; D020249:Hormone Replacement Therapy; D006801:Humans; D007006:Hypogonadism / Q000097:blood* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013739:Testosterone / Q000008:administration & dosage* / Q000097:blood*; D006113:United Kingdom; D014481:United States; D055815:Young Adult
chemical_list: D013739:Testosterone