Prevalence and prognosis of a low serum testosterone in men with type 2 diabetes: the Fremantle Diabetes Study Phase II.
Because published studies have usually involved imprecise assays and selected patients with limited additional data and follow-up, the consequences of a low serum testosterone in diabetes are unclear. This study assessed the prevalence, associates and prognosis of a low testosterone in community-dwelling men with type 2 diabetes.



Longitudinal observational study.



788 men (mean ± SD age: 65·8 ± 11·3 years) followed for 4·0 ± 1·1 years.



Serum testosterone, SHBG, erectile dysfunction (ED; Sexual Health Inventory for Men score <22), anaemia (haemoglobin <130 g/l), all-cause mortality.



The mean ± SD total serum testosterone by liquid chromatography/mass spectrometry was 13·1 ± 5·9 nmol/l (30·6% <10 nmol/l). Most men with a total testosterone <10 nmol/l (67·0%) had a normal/low serum LH. Serum testosterone was independently associated with anaemia (P < 0·001), but not ED (P = 0·80), in logistic regression models. The optimal cut-point (Youden Index) for anaemia was 9·8 nmol/l (sensitivity 53·6%, specificity 75·4%). During the follow-up, 102 men (12·9%) died. There was a U-shaped relationship between total serum testosterone quintiles and death (P = 0·003, log rank test). The middle quintile (>11·1 to ≤13·7 nmol/l) had the lowest risk and there was a 78% increased risk for highest (>16·9 nmol/l) vs lowest (≤8·6 nmol/l) quintile in Cox proportional hazards modelling (P = 0·036). Free serum testosterone and SHBG quintiles were not associated with death.



These data provide some support for the general conventional serum testosterone <10 nmol/l cut-point in identifying an increased risk of anaemia and the subsequent death in men with type 2 diabetes, but indicate that high-normal levels are also an adverse prognostic indicator.
School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, Australia.|Department of Endocrinology and Diabetes, Fiona Stanley and Fremantle Hospitals, Murdoch and Fremantle, WA, Australia.
Emma J
EJ
Hamilton
School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, Australia.
Wendy A
WA
Davis
School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, Australia.|Department of Endocrinology and Diabetes, Fiona Stanley and Fremantle Hospitals, Murdoch and Fremantle, WA, Australia.
Ashley
A
Makepeace
Department of Biochemistry, PathWest Laboratory Medicine WA, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.
Ee Mun
EM
Lim
School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, Australia.|Department of Endocrinology and Diabetes, Fiona Stanley and Fremantle Hospitals, Murdoch and Fremantle, WA, Australia.
Bu B
BB
Yeap
School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, Australia.
Kirsten E
KE
Peters
School of Medicine and Pharmacology, University of Western Australia, Crawley, WA, Australia.
Timothy M E
TM
Davis
D000368:Aged; D000740:Anemia / Q000209:etiology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications / Q000401:mortality; D007172:Erectile Dysfunction / Q000097:blood / Q000209:etiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D013739:Testosterone / Q000097:blood* / Q000172:deficiency
D013739:Testosterone