Application value of D-dimer testing and Caprini risk assessment model (RAM) to predict venous thromboembolism (VTE) in Chinese non-oncological urological inpatients: a retrospective study from a tertiary hospital

BACKGROUND: The Caprini risk assessment model (RAM) and D-dimer testing have been widely used in the prediction of venous thromboembolism (VTE). However, the clinical significance of these testing options are limited in non-oncological urological inpatients because of the low specificity. METHODS: This retrospective study included 1,453 patients who were admitted to the non-oncological unit of the Department of Urology, Xiangya Hospital, Central South University, from January 2018 to December 2018. The highest score of Caprini RAM and the highest D-dimer level were collected in this retrospective study. Ultrasound examinations of the lower extremities or computed tomographic pulmonary arteriography (CTPA) were applied to patients who were suspected of having VTE, if necessary. RESULTS: A total of 1,453 patients were collected in this study, which included 34 VTE and 1,419 non-VTE patients. The threshold of D-dimer was 0.89 µg/mL, according to the receiver operating characteristic (ROC) curve, with a sensitivity of 82.4%, a specificity of 83.3%, and a negative predictive value (NPV) of 99.5%. The cut-off of the Caprini RAM was 5, with a sensitivity of 76.5%, a specificity of 58.7%, and an NPV of 99.0%. The area under the curve (AUC) was higher for D-dimer (0.86) than for the Caprini score (0.73). CONCLUSIONS: The application of 0.89 µg/mL and a score of 5 as cut-offs for D-dimer testing and Caprini RAM, respectively, could safely decrease the proportion of Chinese non-oncological urological inpatients who needed to undergo further examinations. These new findings may enhance the application value of D-dimer testing and Caprini RAM for Chinese non-oncological urological inpatients.