Abstract
STUDY QUESTION: Is it possible to identify a reliable marker of successful sperm retrieval (+SR) in men with idiopathic non-obstructive azoospermia (iNOA) undergoing microdissection testicular sperm extraction (mTESE)? SUMMARY ANSWER: A higher likelihood of +SR during mTESE is observed in men with iNOA and lower preoperative serum anti-Müllerian hormone (AMH) levels, with good predictive accuracy achieved using an AMH threshold of <4 ng/ml. WHAT IS KNOWN ALREADY: AMH has been previously linked to +SR in men with iNOA undergoing mTESE prior to ART. STUDY DESIGN, SIZE, DURATION: A multi-centre cross-sectional study was carried out with a cohort of 117 men with iNOA undergoing mTESE at three tertiary-referral centres. PARTICIPANTS/MATERIALS, SETTING, METHODS: Data from 117 consecutive white-European men with iNOA presenting for primary couple's infertility associated with a pure male factor at three centres were analysed. Descriptive statistics was applied to compare patients with negative (-SR) versus +SR at mTESE. Multivariate logistic regression models were fitted to predict +SR at mTESE, after adjusting for possible confounders. Diagnostic accuracy of the factors associated with +SR was assessed. Decision curve analyses were used to display the clinical benefit. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, 60 (51.3%) men had an -SR and 57 (48.7%) had a +SR at mTESE. Patients with +SR had lower levels of baseline AMH (P = 0.005) and higher levels of estradiol (E2) (P = 0.01). At multivariate logistic regression analysis, lower levels of AMH (odds ratio: 0.79; 95% CI: 0.64-0.93, P = 0.03) were associated with +SR at mTESE, after adjusting for possible confounders (e.g. age, mean testicular volume, FSH, and E2). A threshold of AMH <4 ng/ml achieved the highest accuracy for +SR at mTESE, with an AUC of 70.3% (95% CI: 59.8-80.7). Decision curve analysis displayed the net clinical benefit of using an AMH <4 ng/ml threshold. LIMITATIONS, REASONS FOR CAUTION: There is a need for external validation in even larger cohorts, across different centres and ethnicities. Systematic reviews and meta-analysis to provide high level of evidence are lacking in the context of AMH and SR rates in men with iNOA. WIDER IMPLICATIONS OF THE FINDINGS: Current findings suggest that slightly more than one in two men with iNOA had -SR at mTESE. Overall, men with iNOA with lower levels of AMH had a significantly higher percentage of successful SR at surgery. A threshold of <4 ng/ml for circulating AMH ensured satisfactory sensitivity, specificity, and positive predictive values in the context of +SR at mTESE. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by voluntary donations from the Urological Research Institute (URI). All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.