Objective To investigate the effect of chronic altitude hypoxia exposure on serum lipoprotein levels in healthy subjects and patients with pulmonary hypertension, and whether there is a difference in serum lipoprotein levels between patients with pulmonary hypertension at middle and high altitude. Methods The case data of 245 Han patients with COPD complicated with pulmonary hypertension admitted to the Affiliated Hospital of Qinghai University from January 2018 to September 2022 were retrospectively analyzed. According to the altitude of their long-term residence before onset, the patients were divided into two groups, 119 cases in the middle altitude group (1500 m~2500 m). 126 cases were in the high altitude group of 2500 m~4500 m. In addition, the physical examination data of 50 healthy people in the intermediate and high altitude groups were collected as the control group (the age and gender of the healthy people in the same altitude group were similar to those in the COPD-PH group), a total of 4 groups were collected. The general data, pulmonary artery systolic blood pressure (PASP), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) of the four groups were compared, and the correlation between pulmonary artery systolic blood pressure (PASP) and related variables was analyzed. ResultsThere were no significant differences in age, gender, smoking and drinking between the healthy control group and COPD-PH group (all P>0.05). There were significant differences in body mass index, PASP, TC, TG, HDL-C, LDL-C, TG/HDL-C, HDL-C/LDL-C between the healthy control group and the COPD-PH group (all P<0.05). In the healthy control group, only BMI was significantly different between the high altitude group and the middle altitude group (P<0.05). In the COPD-PH group, PASP, BMI, TC, HDL-C and TG/HDL-C in the high altitude group were significantly different from those in the moderate altitude group (all P<0.05). There were no significant differences in age, gender, smoking, drinking, TG, LDL-C and HDL-C/LDL-C between the two groups (all P>0.05), when gender, age, altitude, body mass index, PASP, smoking and drinking were included in the multi-factor linear regression equation of lipoprotein (TC, TG, HDL-C and LDL-C), it was found that different elevations (middle and higher elevations) only had statistically different effects on HDL-C (b=-0.046, t=-2.209, P=0.028). Correlation analysis showed that PASP was not correlated with age, altitude, body mass index and blood lipids (TC, TG, HDL-C, LDL-C) in the healthy control group (all P>0.05). However, in the COPD-PH group, PASP was negatively correlated with blood lipid indicators (TC, HDL-C and LDL-C). PASP was positively correlated with altitude (a risk factor for hypoxia). ConclusionsHypoxia environment factors characterized by altitude are closely related to the severity of pulmonary artery pressure in patients with COPD-PH, and higher pulmonary artery systolic pressure is closely related to lower levels of TC, HDL-C and LDL-C.