Epidemiological patterns of pulmonary hypertension at 3,658 meters: insights from a Tibet plateau retrospective study

High altitude environment exerts a significant impact on the pathophysiology of various types of pulmonary hypertension, yet the clinical characteristics of pulmonary hypertension in high altitude areas remain unclear. The purpose of this study was to clarify the type distribution and clinical features of pulmonary hypertension in high-altitude regions.

A retrospective study was conducted. Consecutive inpatients who underwent complete Doppler echocardiography and were diagnosed with pulmonary hypertension at the People's Hospital of Xizang Autonomous Region from January 2014 to January 2019 were enrolled. Their demographic data, etiological information, laboratory indicators and echocardiographic parameters were collected. Patients were divided into five groups according to clinical classification criteria, and the differences among the groups were compared.

A total of 312 patients with pulmonary hypertension were enrolled, with a mean age of 60±14 years, including 164 males (52.6%) and 148 females (47.4%). The subjects were predominantly of Zang ethnicity (295 cases, 94.6%), with a mean residential altitude of 3,865±409 meters. According to the World Health Organization (WHO) clinical classification, Group 3 accounted for the highest proportion (66.0%), followed by Group 2 (16.0%), Group 1 (12.8%), Group 5 (2.9%) and Group 4 (2.2%). The main etiologies were chronic obstructive pulmonary disease (COPD)/emphysema (31.1%) and high altitude pulmonary hypertension (HAPH) (29.5%). Patients in Group 3 had the highest proportion of males (62.1%), the oldest age and the highest smoking rate (39.8%), and their hemoglobin, hematocrit and red blood cell count were significantly higher than those in other groups (all P<0.01).

Group 3 is the most common type of pulmonary hypertension in hospitalized patients in high-altitude areas, with the main etiologies being COPD/emphysema and HAPH.