[Analysis of the relationship between epistaxis and homocysteine and climatic factors in ultra-high altitude area].

<b>Objective:</b>To analyze the related influencing factors of epistaxis in extremely high altitude area, and to provide evidence for the prevention and treatment of epistaxis in extremely high altitude area. <b>Methods:</b>From January 2021 to December 2022, 206 outpatients with epistaxis, 54 inpatients with epistaxis and 69 inpatients withoutepistaxis in theDepartment of Otorhinolarygology, Naqu People's Hospital were collected. The previous history, drinking history, smoking history, serum homocysteine（Hcy）, white blood cell count（WBC）, red blood cell count（RBC）, hematocrit（HCT）, hemoglobin（HGB） and mean hemoglobin concentration（MCHC） were compared between inpatients with or without epistaxis. The factors with significant differences were analyzed by binary Logistic regression. The monthly average temperature,air pressure, humidity and 2-minute wind speed were collected from January 2021 to December 2022 in Naqu City to analyze the correlation between epistaxis and climate factors. <b>Results:</b>The number of patients with hypertension in the case group was more than that in the control group, and the difference was significant（<i>P</i>=0.013）. Serum Hcy level in the case group was higher than that in the control group（<i>P</i><0.001）. RBC, HCT, HGB and MCHC were lower than that in the control group（<i>P</i>=0.001, 0.001, 0.001, 0.039）, and the difference was significant. History of hypertension and Hcy were risk factors for epistaxis. Patients with a history of hypertension were 3.713 times more likely to suffer from epistaxis than those without a history of hypertension（<i>P</i>=0.022）. Each 1 increase in Hcy concentration increased the risk of epistaxis by 13.1%（<i>P</i>=0.001）. <b>Conclusion:</b>Patients with epistaxis in Naqu area had higher serum Hcy level and lower RBC, HCT, HGB and MCHC. History of hypertension and Hcy were risk factors for epistaxis. Patients with a history of hypertension were 3.713 times more likely to suffer from epistaxis than those without a history of hypertension. Every 1 increase in Hcy concentration increased the risk of epistaxis by 13.1%. Active intervention of hypertension and serum Hcy can effectively prevent the incidence of epistaxis.