Background:
Post-operative venous thromboembolism (VTE) is a major preventable cause of morbidity and mortality. The risk may be greater in patients who undergo major surgery for head and neck cancer compared to other otolaryngological operations, however the use of thromboprophylaxis varies among surgeons. The objective of this study was 1) to utilize a large database to determine the prevalence of VTE in head and neck cancer and 2) to compare the efficacy and cost-effectiveness of prophylactic heparin and enoxaparin.
Methods: The TriNetX Research Network was utilized to identify patients with a diagnosis of head and neck cancer treated with surgery between 2011-2021. The prevalence of VTE in the first 30 days and time on prophylaxis following surgery were obtained.
A break-even analysis was performed. The costs of anticoagulant agents were obtained from our institution’s drug wholesaler. A range of reported VTE rates and VTE-related medical costs were determined from existing literature. The absolute risk reduction (ARR) was the percentage by which a prophylactic measure must reduce the rate of VTE in order to make it economically justifiable.
Results: A cohort of 26,071 patients were included in the analysis. The mean age was 62.3 years and 69% were male. 49.0% did not receive thromboprophylaxis, while 20.5% were prescribed heparin, 25.2% enoxaparin, and 5.3% were prescribed other anticoagulant agents or a combination. Those on heparin or enoxaparin remained on therapy for an average of 6.8 and 4.8 days, respectively. Patients prescribed thromboprophylaxis versus those who were not had significantly increased rates of hyperlipidemia (p = 0.02), ischemic heart disease, heart failure, cerebrovascular disease, COPD, and hypertension (p < 0.0001). In aggregate, there were 566 cases (2.17%) of VTE. The rate was 1.43% in the non-thromboprophylaxis group, and 2.47% and 2.11% in those prescribed heparin and enoxaparin, respectively. There was no significant difference in prevalence of VTE between patients prophylactically treated with heparin versus enoxaparin. Additionally, there were no significant differences in comorbidities between those who were not anticoagulated and experienced VTE and those who were with the same outcome.
At $0.40 - $3.91 per dose, heparin was determined to be cost-effective if the VTE rate decreased by an ARR of 0.06% - 0.58%. At $3.38 - $30.07 per dose, enoxaparin would be cost-effective if it decreased the VTE rate by at least 0.17% - 1.48% (Table 1).
Conclusion: Post-surgical head and neck cancer patients with increased comorbidities were more likely to be prescribed thromboprophylaxis and experience VTE, though the overall rate of VTE in this cancer population remains low. The group that did not receive thromboprophylaxis and went on to develop VTE represents a high-risk group and potential area for intervention. The use of heparin was equally effective while providing cost savings as compared to enoxaparin. Evaluating different prophylaxis regimens and further risk stratification among patient populations may allow for effective and cost-efficient prophylaxis.