Factors attributing to the failure of endometrial sampling in women with postmenopausal bleeding

To determine which doctor- and patient-related factors affect failure of outpatient endometrial sampling in women with postmenopausal bleeding, and to develop a multivariable prediction model to select women with a high probability of failed sampling. Prospective multicenter cohort study. Three teaching hospitals in the Netherlands. Women presenting with postmenopausal bleeding with an indication for endometrial sampling. Multivariable logistic regression was performed to evaluate the impact of doctor's training level and patient's characteristics on failure of sampling. Failure of endometrial sampling, classified as technical failure or insufficient tissue for diagnosis. In 74 (20.8%) of the 356 included women, sampling technically failed, and in 84 (29.8%) the amount of tissue was insufficient for diagnosis. Nulliparity [odds ratio (OR) 3.8, 95% confidence interval (CI) 1.8-7.9] and advanced age (OR 1.03 per year, 95% CI 1.00-1.06) were associated with technical failure. Advanced age was associated with insufficient sampling (OR 1.04 per year, 95% CI 1.01-1.07), and endometrial thickness >12 mm decreased the chance of insufficient sampling (OR 0.3, 95%CI 0.1-0.8). The prediction model for total failure had an area under the ROC curve of 0.64 (95% CI 0.58-0.70). In women with postmenopausal bleeding, the failure rate of endometrial sampling is relatively high and is associated with nulliparity and advanced age. Endometrial thickness >12 mm decreased the chance of failure. A multivariable prediction model for total failure based on patient characteristics has a moderate capacity to discriminate between women at high or low risk of failure