Leijdekkers JA, et al. - Researchers explored if the published pre-treatment and post-treatment McLernon models, predicting cumulative live birth rates (LBR) over multiple complete IVF cycles, are valid in a different context. Accurate prediction of cumulative LBR in a different geographical context and a more recent time period via both McLernon models, with minor recalibration of the pre-treatment model, was achieved.

Methods

• Researchers performed an external validation study in an independent prospective cohort of 1515 Dutch women who participated in the OPTIMIST study (NTR2657) and underwent their first IVF treatment between 2011 and 2014.
• A total of 2881 complete treatment cycles were performed on the participants; a complete cycle was defined as all fresh and frozen thawed embryo transfers resulting from one episode of ovarian stimulation.
• After inclusion, follow up of 18 months was performed.
• The primary outcome included ongoing pregnancy leading to live birth.
• Using the linear predictor as described by McLernon et al. to calculate the probability of a live birth, they externally validated model performance up to three complete treatment cycles.
• The c-statistic expressed the discrimination and a calibration plot depicted calibration graphically.
• In contrast to the original model development cohort, the OPTIMIST cohort had anti-Müllerian hormone (AMH), antral follicle count (AFC) and body weight available; they evaluated these measures as potential additional predictors for model improvement.

Results

• Researchers identified the c-statistic of the pre-treatment model of 0.62 (95% CI: 0.59–0.64) and of the post-treatment model of 0.71 (95% CI: 0.69–0.74) on applying the McLernon models to the OPTIMIST cohort.
• The calibration plot of the pre-treatment model indicated a slight overestimation of the cumulative LBR.
• They recalibrated the pre-treatment model by subtracting 0.35 from the intercept to improve calibration.
• Accurate cumulative LBR predictions were achieved by the post-treatment model calibration plot.
• Addition of AMH, AFC and body weight to the McLernon models led to slight improvement in the c-statistic of the updated pre-treatment model to 0.66 (95% CI: 0.64–0.68), and however, the c-statistic of the updated post-treatment model remained at the previous level of 0.71 (95% CI: 0.69–0.73).
• Increase in a chance of 40% of a live birth from the first complete cycle to 72% over three complete cycles was noted in a woman aged 30 years with 2 years of primary infertility who starts ICSI treatment for male factor infertility using the recalibrated pre-treatment model.
• The updated pre-treatment model revises the estimated chance of a live birth to 30% in the first complete cycle and 59% over three complete cycles if this woman weighs 70 kg, has an AMH of 1.5 ng/mL and an AFC of 10 measured at the beginning of her treatment.
• If this woman then has five retrieved oocytes, no embryos cryopreserved and a single fresh cleavage stage embryo transfer in her first ICSI cycle, the chances of a live birth at 28% and 58%, respectively, were estimated via the post-treatment model.