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

Objective 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. Design Prospective multicenter cohort study. Setting Three teaching hospitals in the Netherlands. Population Women presenting with postmenopausal bleeding with an indication for endometrial sampling. Methods Multivariable logistic regression was performed to evaluate the impact of doctor's training level and patient's characteristics on failure of sampling. Main outcome measures Failure of endometrial sampling, classified as technical failure or insufficient tissue for diagnosis. Results 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). Conclusions 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.