SUN-228 Opioid Use Is Not Associated with Clinical Hypogonadism in Men with Chronic Non-Cancer Pain

Introduction: Opioid analgesia is widely used in the management of chronic pain despite lacking a strong evidence base of efficacy and concerns about adverse effects. Opioid use has been associated with hypogonadotrophic hypogonadism in a limited number of small chronic pain studies. Aim: To determine the prevalence and degree of hypogonadism in men with chronic non-malignant pain treated with or without opioid analgesia. Method: A cross-sectional study of community dwelling Australian men over the age of 18yrs with chronic non-cancer pain of at least 6 months duration attending a single multidisciplinary pain clinic between February 2016 to August 2017, and who were managed either with or without opioid therapy for a minimum of 6 weeks. Men with known pituitary or testicular causes of hypogonadism, previous or current testosterone use, and men treated with androgen deprivation therapy were excluded. Men completed questionnaires about sexual function (International Index of Erectile Function-5), pain (Brief Pain Inventory (BPI)) and mood (Depression, Anxiety and Stress Scale (DASS21)). Medications, age and BMI were recorded. Blood was obtained to assess serum total testosterone (TT), FSH, LH and prolactin (mean ± SD) between the two groups. TT levels were measured using gold standard liquid chromatography-tandem mass spectrometry. Results: Participants were 50 men treated with oral or transdermal opioids (oral morphine equivalent daily dose (oMEDD) 100 ± 92mg) and 37 men managed without opioids. Age (48.8 ± 11.5 vs 51 ± 16.3 yrs) and BMI (28.7 ± 5.0 vs 27.8 ± 4.5) were similar. Mean serum TT levels were within the normal range for both groups although were lower in the opioid vs non-opioid group (13.3 ± 6.1 vs 15.9 ± 5.5 nmol/L [383 ± 175.6 vs 457.9 ± 158.4 ng/dL], p=0.04). TT was < 8nmol/L [<230 ng/dL] in 9/50 men from the opioid group and 3/37 men from the non-opioid group. TT was negatively correlated with BMI in both groups. There was no difference in the opioid vs non-opioid treated men in serum FSH (6.6 ± 3.5 vs 6.3 ± 3.2 IU/L, p=0.63), LH (4.0 ± 2.2 vs 4.8 ± 1.9 IU/L, p=0.06) or prolactin (193 ± 97 vs 178 ± 98 mIU/L, p=0.48). TT levels did not correlate with oMEDD across the group nor in the subset of men (n=17) on oMEDD > 100mg per day. Sexual function scores were similar between the groups and did not correlate with TT. Men taking opioids reported higher severity and intensity of pain (BPI), and higher anxiety, depression and stress levels (DASS21). Discussion: There was no clinically significant association between opioid use or dose and TT in this cohort of men with chronic non-cancer pain. Previous smaller studies of men with chronic non-cancer pain documenting lower testosterone levels have utilised significantly higher oMEDD suggesting a possible threshold dose effect. Although opioid use may contribute to hypogonadism in some men, this should not preclude endocrine evaluation to identify other causes.