title: Prevalence and influence of diagnostic criteria in the assessment of hypogonadism in intrathecal opioid therapy patients.
abstract: BACKGROUND
  Hypogonadism is frequently diagnosed based on total testosterone (TT) levels alone. However, 99% of testosterone is bound to the sex hormone-binding globulin (SHBG) with only 1% free testosterone. Alternative assessment methods consist of assay of free testosterone (FT) or bioavailable testosterone (BT) by equilibrium dialysis, calculation of FT and BT through the Vermeulen equations, and calculation of the free androgen index (FAI).
  
  
  OBJECTIVE
  The aim of this study was to investigate the prevalence of hypogonadism in male chronic non-cancer pain patients undertaking long-term intrathecal opioid therapy and the existence of diagnostic discrepancies according to the criteria used.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Department of Pain Management, Russells Hall Hospital, Dudley, United Kingdom.
  
  
  METHODS
  Twenty consecutive male patients undertaking long-term intrathecal opioid therapy had the gonadal axis evaluated by assays of luteinising hormone (LH), follicle stimulating hormone (FSH), TT, SHBG and by calculating the FT, BT and FAI.
  
  
  RESULTS
  Hypogonadism was present in 17 (85%) of the patients based on TT; 17 (85%) according to FT and BT calculations; and 14 (70%) when calculating FAI. Based on either TT or FT being low or borderline/low, 19 (95%) of the investigated patients were biochemically hypogonadal. Significant differences were observed between diagnosis based on FT and FAI (P < 0.05). No significant differences were observed between diagnosis based on TT and FT (P = 0.40) or TT and FAI (P = 0.20).
  
  
  CONCLUSIONS
  Hypogonadism is common in patients undertaking intrathecal opioid therapy for the management of chronic non-malignant pain; however, diagnostic criteria can influence the diagnosis of this side effect. The assessment of the hypothalamic-pituitary-gonadal axis should include evaluation of total serum testosterone, free testosterone, or bioavailable testosterone.
authors: Birmingham City University, Birmingham, UK. ruivduarte@gmail.com
authors: Rui V
authors: RV
authors: Duarte
authors: Jon H
authors: JH
authors: Raphael
authors: Mourad
authors: M
authors: Labib
authors: Jane L
authors: JL
authors: Southall
authors: Robert L
authors: RL
authors: Ashford
mesh_terms: D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects*; D059350:Chronic Pain / Q000188:drug therapy; D006801:Humans; D007006:Hypogonadism / Q000139:chemically induced* / Q000175:diagnosis* / Q000453:epidemiology*; D015918:Infusion Pumps, Implantable; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013739:Testosterone / Q000097:blood
chemical_list: D000701:Analgesics, Opioid; D013739:Testosterone