Low Free Testosterone Is Associated with Hypogonadal Signs and Symptoms in Men with Normal Total Testosterone.

CONTEXT: During aging, total testosterone (TT) declines and SHBG increases, resulting in a greater decrease in calculated free T (cFT). Currently, guidelines suggest using TT to diagnose androgen deficiency and to reserve cFT only for men with borderline TT. OBJECTIVE: Our objective was to investigate if either low cFT or low TT is more strongly associated with androgen-related clinical endpoints. METHODS: A total of 3334 community-dwelling men, aged 40-79 years, were included in this study. Differences in clinical variables between the referent group of men with both normal TT (≥10.5 nmol/liter) and normal cFT (≥220 pmol/liter) with those who had normal TT/low cFT, low TT/normal cFT, and low TT/low cFT were assessed by regression models adjusted for age, center, body mass index, and comorbidities. RESULTS: A total of 2641 men had normal TT (18.4 ± 5.5 [mean ± SD] nmol/liter)/normal cFT (326 ± 74 pmol/liter), 277 men had normal TT (14.2 ± 3.7)/low cFT (194 ± 23), 96 men had low TT (9.6 ± 0.7)/normal cFT (247 ± 20), and 320 men had low TT (7.8 ± 2.5)/low cFT (160 ± 55). Men with normal TT/low cFT were older and in poorer health. They had higher SHBG and LH and reported more sexual and physical symptoms, whereas hemoglobin and bone ultrasound parameters were lower compared to the referent group. Men with low TT/normal cFT were younger and more obese. They had lower SHBG, but LH was normal, whereas features of androgen deficiency were lacking. CONCLUSIONS: Low cFT, even in the presence of normal TT, is associated with androgen deficiency-related symptoms. Normal cFT, despite low TT, is not associated with cognate symptoms; therefore, cFT levels should be assessed in men with suspected hypogonadal symptoms.

Dipeptidyl peptidase-4 inhibition and narrow-band ultraviolet-B light in psoriasis (DINUP): study protocol for a randomised controlled trial.

BACKGROUND: Moderate to severe psoriasis is a systemic inflammatory disease associated with insulin resistance, obesity and type 2 diabetes (T2DM). Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that improves glycaemia and has a marketing authorisation for the treatment of T2DM. Non-immunosuppressive therapies that are effective for psoriasis and its associated comorbidities would be a significant advance in the treatment of this chronic disease. METHODS/DESIGN: This is a single centre, 39-week, prospective, randomised, open label, clinical trial of oral sitagliptin (Januvia(®)) in psoriasis patients who are due to undergo a course of narrow-band ultraviolet-B (NB-UVB) phototherapy. We plan to enrol 120 participants and allocate participants on a random and 1:1 basis to receive sitagliptin 100 mg daily for 24 weeks combined with NB-UVB or NB-UVB monotherapy. Participants will be followed up for 12 weeks after sitagliptin therapy is discontinued. The primary endpoint is the change in Psoriasis Area and Severity Index (PASI) 24 weeks after treatment initiation. Secondary endpoints include cumulative NB-UVB dose, number of NB-UVB treatments required to clear psoriasis, proportions of participants who achieve PASI-50 (50 % reduction in PASI from baseline), PASI-75, PASI-90 and the proportion of participants who relapse in each group. We will also analyse changes in cardiovascular disease risk factors, serum cytokine and hormone levels and peripheral blood mononuclear expression of immune proteins at 24 and 36 weeks. A subgroup of participants will have skin biopsies taken and analysed for skin levels and expression of immune cells, receptors, hormones and immune proteins. The genetic or epigenetic profile that predicts best response to DPP-4 inhibitor therapy will be analysed. The safety endpoints include the rate and severity of adverse events. DISCUSSION: This is the first randomised clinical trial assessing dipeptidyl peptidase-4 inhibition therapy in psoriasis. We hypothesise that sitagliptin therapy in combination with NB-UVB improves psoriasis severity compared to NB-UVB monotherapy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02347501 (Date of registration: 27 January 2015).