The limited utility of currently available venous thromboembolism risk assessment tools in gynecological oncology patients.

BACKGROUND: Use of risk assessment tools, such as the Caprini score or Rogers score, is recommended by national societies to stratify surgical patients by venous thromboembolism risk and guide prophylaxis. However, these tools were not developed in a gynecological oncology patient population, and their utility in this population is unknown.
OBJECTIVE: The objective of the study was to examine the ability of both the Caprini and Rogers scores to stratify gynecological oncology patients by the risk of venous thromboembolism. STUDY
DESIGN: Patients undergoing surgery for cervical, ovarian, uterine, vaginal, and vulvar cancers between 2008 and 2013 were identified from the National Surgical Quality Improvement Program Database using International Classification of Diseases, ninth revision, codes. The Caprini and Rogers scores were calculated for each patient based on the recorded demographic and procedure data. Venous thromboembolism events were recorded for 30 days postoperatively. Patients were categorized into risk groups based on the calculated Caprini and Rogers scores and the incidence of venous thromboembolism, and the 95% confidence interval was estimated for each of these groups. The relationship between the risk score and venous thromboembolism incidence was examined with Pearson's correlation coefficient.
RESULTS: Of 17,713 patients, 1.8% developed a venous thromboembolism. No patients were classified by the Caprini score as low risk, 0.1% were moderate risk, 3.0% were higher risk (score 4), and 96.9% were highest risk (score ≥5). The Caprini score groupings did not correlate with venous thromboembolism. The high-risk group had a paradoxically higher incidence of venous thromboembolism of 2.5% compared with the highest-risk group, 1.7% (P = .40). However, when the highest-risk group of the Caprini score was substratified, it was highly correlated with venous thromboembolism (R(2) = 0.93). For the Rogers score, only 0.2% of patients were low risk (score <7), 36.9% were medium risk (score 7-10), and 63.0% were high risk (score >10). When the highest risk group of the Rogers score was substratified, it was also highly correlated with venous thromboembolism (R(2) = 0.99).
CONCLUSION: Gynecological oncology patients score very high on current venous thromboembolism risk assessment models. The Caprini score is limited in its ability to discriminate relative venous thromboembolism risk among gynecological oncology patients because 97% are in the highest-risk category. Substratification of the highest-risk groups allows for relative venous thromboembolism risk stratification among gynecological oncology patients, suggesting that further evaluation of risk stratification is needed in gynecological oncology surgery.