THE PREVALENCE AND RISK FACTORS OF HIGH-ALTITUDE PULMONARY HYPERTENSION AMONG THE HIGHLANDERS IN TIBETAN AREA

Abstract

Objective: The study aimed to investigate the prevalence and risk factors of high-altitude pulmonary hypertension (HAPH) among the highlanders living at 3500m above sea level in Tibetan area of China. Design and method: we conducted a cross-sectional survey on the permanent Tibetans residing at an average altitude of 3500m. Age 18 years and above were selected by stratified cluster random sampling technique and screened for recording questionnaire, anthropometric indices, blood pressure, biochemical factors and echocardiography. HAPH was defined as mean pulmonary artery pressure over30mmHg indicated by echocardiography. Data of 1130 subjects were analyzed who were free of polycythemia and cardiorespiratory diseases to determine the prevalence of HAPH and its predisposing factors. Results: The prevalence of HAPH was different in males and females (8.7% vs 4.6%,P = 0.033). Patients with hypertension are more likely to develop HAPH compared with normal blood pressure (9.6% vs 4.4%,P = 0.010). T-test analysis suggested that patients with HAPH had lower pulse oxygen saturation and estimated glomerular filtration rate. In addition, patients with HAPH have more significant metabolic abnormalities (including elevated blood pressure, blood glucose, triglyceride, low density lipoprotein cholesterol, uric acid, waist circumference, hip circumference, BMI. all p value < 0.05), patients with HAPH have mildly increased RV, RA, and diameter of the main pulmonary artery. After stepwise multivariate logistic regression, it was suggested that age, hemoglobin level, and increased TG were independent risk factors for HAPH. Conclusions: It can be concluded that HAPH is prevalent in 5.8% of natives of Tibetan area in China. Increasing age, hemoglobin and triglyceride are independent predisposing factors.