title: Elevated Dihydrotestosterone is Associated with Testosterone Induced Erythrocytosis.
abstract: OBJECTIVE
  Erythrocytosis is the most common dose limiting adverse effect of testosterone therapy but the mechanisms of testosterone mediated erythropoiesis remain unclear. In this study we examine risk factors for erythrocytosis associated with testosterone therapy.
  
  
  METHODS
  A retrospective review was performed of 179 hypogonadal men on testosterone therapy at a single andrology clinic. Demographic data, testosterone therapy formulation and duration of treatment, and 5α-reductase inhibitor use were assessed. Serum dihydrotestosterone, total testosterone, free testosterone, follicle-stimulating hormone, luteinizing hormone, hematocrit and lipid levels were extracted, and changes during treatment were determined. Spearman's rank correlation was used to identify relationships between change in hematocrit and study variables.
  
  
  RESULTS
  Of 179 patients 49 (27%) experienced a 10% or greater change in hematocrit and erythrocytosis (hematocrit 50% or greater) developed in 36 (20.1%) at a median followup of 7 months. Topical gels were used by 41.3% of patients, injectable testosterone by 52.5% and subcutaneous pellets by 6.1%. More men who experienced a change in hematocrit of 10% or greater used injectable testosterone than men with a change in hematocrit of less than 10% (65% vs 48%, p=0.035), and were less likely to be on a 5α-reductase inhibitor (2% vs 15%, p=0.017). Men with a change in hematocrit of 10% or greater had higher posttreatment dihydrotestosterone levels (605.0 vs 436.0 ng/dl, p=0.017) and lower luteinizing hormone and follicle-stimulating hormone levels than men with a change in hematocrit of less than 10%. Spearman's rank correlations yielded relationships between change in hematocrit and posttreatment dihydrotestosterone ρ=0.258, p=0.001) and total testosterone (ρ=0.171, p=0.023).
  
  
  CONCLUSIONS
  Dihydrotestosterone may have a role in testosterone therapy related erythrocytosis and monitoring dihydrotestosterone levels during testosterone therapy should be considered. In men in whom erythrocytosis develops, 5α-reductase inhibitors may be therapeutic.
authors.affiliation: Scott Department of Urology, Baylor College of Medicine, Houston, Texas.
authors.forename: Monty
authors.initials: M
authors.lastname: Aghazadeh
authors.affiliation: Scott Department of Urology, Baylor College of Medicine, Houston, Texas; Center for Reproductive Medicine, Baylor College of Medicine, Houston, Texas.
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Pastuszak
authors.affiliation: Scott Department of Urology, Baylor College of Medicine, Houston, Texas.
authors.forename: William G
authors.initials: WG
authors.lastname: Johnson
authors.affiliation: Urology Associates of Mobile, Mobile, Alabama.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: McIntyre
authors.affiliation: Department of Urology, University of California, San Diego, San Diego, California.
authors.forename: T Mike
authors.initials: TM
authors.lastname: Hsieh
authors.affiliation: Scott Department of Urology, Baylor College of Medicine, Houston, Texas; Center for Reproductive Medicine, Baylor College of Medicine, Houston, Texas. Electronic address: larryl@bcm.edu.
authors.forename: Larry I
authors.initials: LI
authors.lastname: Lipshultz
mesh_terms: D000328:Adult; D013196:Dihydrotestosterone / Q000097:blood*; D020249:Hormone Replacement Therapy / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011086:Polycythemia / Q000097:blood* / Q000139:chemically induced*; D012189:Retrospective Studies; D012307:Risk Factors; D013739:Testosterone / Q000009:adverse effects*
chemical_list: D013196:Dihydrotestosterone; D013739:Testosterone
keywords: dihydrotestosterone; hormone replacement therapy; polycythemia; testosterone