The role of green tea intake in thromboprophylaxis of venous thromboembolism in patients with cancer.

BACKGROUND

Green tea intake has been reported to improve the clinical outcomes of patients with cardiovascular diseases or cancer. It may have a certain role in the development of venous thromboembolism (VTE) among cancer patients. The current study aimed to address this issue, which has been understudied.

METHODS

We carried out a retrospective study to explore the role of green tea intake in cancer patients. Patients with and without green tea intake were enrolled in a 1:1 ratio by using propensity scoring matching. The primary and secondary outcomes were VTE development and mortality 1 year after cancer diagnosis, respectively.

RESULTS

The cancer patients with green tea intake ( = 425) had less VTE development (10 [2.4%] vs. 23 [5.4%],  = 0.021), VTE-related death (7 [1.6%] vs. 18 [4.2%],  = 0.026), and fatal pulmonary embolism (PE) (3 [0.7%] vs. 12 [2.8%],  = 0.019), compared with those without green tea intake ( = 425). No intake of green tea was correlated with an increase in VTE development (multivariate hazard ratio (HR) 1.758 [1.476-2.040],  < 0.001) and VTE-related mortality (HR 1.618 [1.242-1.994],  = 0.001), compared with green tea intake. Patients with green tea intake less than 525 mL per day had increased VTE development (area under the curve (AUC) 0.888 [0.829-0.947],  < 0.001; HR1.737 [1.286-2.188],  = 0.001) and VTE-related mortality (AUC 0.887 [0.819-0.954],  < 0.001; HR 1.561 [1.232-1.890],  = 0.016) than those with green tea intake more than 525 mL per day. Green tea intake caused a decrease in platelet ( < 0.001) instead of D-dimer ( = 0.297). The all-cause mortality rates were similar between green tea (39 [9.2%]) and non-green tea (48 [11.3%]) intake groups ( = 0.308), whereas the VTE-related mortality rate in the green tea intake group (7 [1.6%]) was lower than that of the non-green tea intake group (18 [4.2%]) ( = 0.026). The incidences of adverse events were similar between the green tea and non-green tea intake groups.

CONCLUSION

In conclusion, the current study suggests that green tea intake reduces VTE development and VTE-related mortality in cancer patients, most likely through antiplatelet mechanisms. Drinking green tea provides the efficacy of thromboprophylaxis for cancer patients.