Prediction model for obtaining spermatozoa with testicular sperm extraction in men with non-obstructive azoospermia

Abstract

Studyquestion: Can an externally validated model, based on biological variables, be developed to predict successful sperm retrieval with testicular sperm extraction (TESE) in men with non-obstructive azoospermia (NOA) using a large nationwide cohort? summaryanswer: Our prediction model including six variables was able to make a good distinction between men with a good chance and men with a poor chance of obtaining spermatozoa with TESE. what is known already: Using ICSI in combination with TESE even men suffering from NOA are able to father their own biological child. Only in approximately half of the patients with NOAcan testicular sperm be retrieved successfully. The few models that have been developed to predict the chance of obtaining spermatozoa with TESE were based on small datasets and none of them have been validated externally. study design, size, duration: We performed a retrospective nationwide cohort study. Data from 1371 TESE procedures were collected between June 2007 and June 2015 in the two fertility centres. participants/materials, setting, methods: All men with NOA undergoing their first TESE procedure as part of a fertility treatmentwereincluded.Theprimaryend-pointwas thepresence ofone ormore spermatozoa (regardless of theirmotility) in the testicularbiopsies. We constructed a model for the prediction of successful sperm retrieval, using univariable and multivariable binary logistic regression analysis and the dataset from one centre. This model was then validated using the dataset from the other centre. The area under the receiver-operating characteristic curve (AUC) was calculated and model calibration was assessed. main results and the role of chance: There were 599 (43.7%) successful sperm retrievals after a first TESE procedure. The prediction model, built after multivariable logistic regression analysis, demonstrated that higher male age, higher levels of serum testosterone and lower levels of FSH and LH were predictive for successful sperm retrieval. Diagnosis of idiopathic NOA and the presence of an azoospermia factor c gene deletionwere predictive for unsuccessful spermretrieval.TheAUCwas 0.69 (95%confidence interval (CI): 0.66-0.72).The difference between themeanobserved chance and themeanpredicted chancewas <2.0%in all groups, indicating good calibration. In validation, themodel had moderate discriminative capacity (AUC 0.65, 95% CI: 0.62-0.72) and moderate calibration: the predicted probability never differed by more than 9.2% of the mean observed probability. limitations, reasons for caution: The percentage of men with Klinefelter syndrome among men diagnosed with NOA is expected to be higher than in our study population, which is a potential selection bias. The ability of the sperm retrieved to fertilize an oocyte and produce a live birth was not tested. wider implications of the findings: This model can help in clinical decision-making in men withNOA by reliably predicting the chance of obtaining spermatozoa with TESE. study funding/competing interest: This studywas partly supported by an unconditional grant fromMerck Serono (to D.D.M.B. and K.F.) and by the Department of Obstetrics and Gynaecology of Radboud University Medical Center, Nijmegen, TheNetherlands, the Department of Obstetrics and Gynaecology, Jeroen Bosch Hospital, Den Bosch, The Netherlands, and the Department of Obstetrics and Gynaecology, Academic Medical Center, Amsterdam, The Netherlands. Merck Serono had no influence in concept, design nor elaboration of this study. trial registration number: Not applicable.