We read with interest the article by van den Boogaard et al.1 that intends to perform an individual patient data (IPD) meta-analysis of subfertile couples and treatment outcomes using the Templeton model to estimate the chance of pregnancy after in vitro fertilisation (IVF). The model of Templeton et al. analysed 36 961 treatment cycles undertaken in the UK between 1991 and 1994, and was validated in a population of 1253 couples receiving IVF treatment in the Netherlands between 1991 and 1999.2,3 Since then intracytoplasmic sperm injection (ICSI) for male factor infertility has been widely adopted, and we have recently demonstrated that the Templeton model, although showing reasonable discrimination, is poorly calibrated and of limited use in contemporary populations.4 Using UK population level data from 144 018 treatment cycles completed from 2003 to 2007, we developed a new model that encompasses a series of new measures, including use of donor oocytes, ICSI, cycle number and whether there had been a previous spontaneous or IVF-related live birth or fetal loss. Using this novel model we demonstrated a statistically significant improvement (compared with the Templeton model) in the overall prediction of live birth, as assessed by area under the curve, and that our model attained excellent calibration, with the accurate identification of couples with a poor, moderate and good prognosis. This model has now been validated on the UK 2008 data for the National Institute for Health and Clinical Excellence (NICE) Guideline Development Group, and underlies the health economic model to estimate live birth probabilities for IVF (NICE Infertility Guideline, released for public consultation 22 May 2012). We would therefore respectfully suggest that the IPD analysis should use the more recent, accurate and now validated IVFpredict model when assessing the chance of a live birth after IVF.


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