External validation and calibration of IVFpredict:A national prospective cohort study of 130,960 in vitro fertilisation Cycles

© 2015 Smith et al. Background Accurately predicting the probability of a live birth after in vitro fertilisation (IVF) is important for patients, healthcare providers and policy makers. Two prediction models (Templeton and IVFpredict) have been previously developed from UK data and are widely used internationally. The more recent of these, IVFpredict, was shown to have greater predictive power in the development dataset. The aim of this study was external validation of the two models and comparison of their predictive ability. Methods and Findings 130,960 IVF cycles undertaken in the UK in 2008-2010 were used to validate and compare the Templeton and IVFpredict models. Discriminatory power was calculated using the area under the receiver-operator curve and calibration assessed using a calibration plot and Hosmer-Lemeshow statistic. The scaled modified Brier score, with measures of reliability and resolution, were calculated to assess overall accuracy. Both models were compared after updating for current live birth rates to ensure that the average observed and predicted live birth rates were equal. The discriminative power of both methods was comparable: the area under the receiver-operator curve was 0.628 (95% confidence interval (CI): 0.625-0.631) for IVFpredict and 0.616 (95% CI: 0.613-0.620) for the Templeton model. IVFpredict had markedly better calibration and higher diagnostic accuracy, with calibration plot intercept of 0.040 (95% CI: 0.017-0.063) and slope of 0.932 (95% CI: 0.839 - 1.025) compared with 0.080 (95% CI: 0.044-0.117) and 1.419 (95% CI: 1.149-1.690) for the Templeton model. Both models underestimated the live birth rate, but this was particularly marked in the Templeton model. Updating the models to reflect improvements in live birth rates since the models were developed enhanced their performance, but IVFpredict remained superior. Conclusion External validation in a large population cohort confirms IVFpredict has superior discrimination and calibration for informing patients, clinicians and healthcare policy makers of the probability of live birth following IVF

BMC Med Educ

BACKGROUND: There is currently an absence of valid and relevant instruments to evaluate how Evidence-based Practice (EBP) training improves, beyond knowledge, physicians' skills. Our aim was to develop and test a tool to assess physicians' EBP skills. METHODS: The tool we developed includes four parts to assess the necessary skills for applying EBP steps: clinical question formulation; literature search; critical appraisal of literature; synthesis and decision making. We evaluated content and face validity, then tested applicability of the tool and whether external observers could reliably use it to assess acquired skills. We estimated Kappa coefficients to measure concordance between raters. RESULTS: Twelve general practice (GP) residents and eleven GP teachers from the University of Bordeaux, France, were asked to: formulate four clinical questions (diagnostic, prognosis, treatment, and aetiology) from a proposed clinical vignette, find articles or guidelines to answer four relevant provided questions, analyse an original article answering one of these questions, synthesize knowledge from provided synopses, and decide about the four clinical questions. Concordance between two external raters was excellent for their assessment of participants' appraisal of the significance of article results (K = 0.83), and good for assessment of the formulation of a diagnostic question (K = 0.76), PubMed/Medline (K = 0.71) or guideline (K = 0.67) search, and of appraisal of methodological validity of articles (K = 0.68). CONCLUSIONS: Our tool allows an in-depth analysis of EBP skills, thus could supplement existing instruments focused on knowledge or specific EBP step. The actual usefulness of such tools to improve care and population health remains to be evaluated