The study of prevalence rate, and clinical characteristics of high altitude deterioration.

OBJECTIVE This study was aimed to investigate the prevalence rate and clinical characteristics of high altitude deterioration (HADT), which would provide a scientific basis for the diagnosis and prevention of HADT. SUBJECTS AND METHODS A total of 175 subjects, who had migrated to a high altitude (4516 m) for more than 1 year, were investigated. A questionnaire survey based on the symptoms of HADT was conducted, and 117 subjects were determined to have HADT according to the diagnostic criteria of HADT. To explore the clinical characteristics of HADT, 117 HADT patients and 31 healthy individuals were assigned to HADT patient group and healthy control group, respectively. Their body mass indexes (BMIs), blood rheology, full blood count (including hemoglobin concentration, leukocyte count, neutrophil count, lymphocyte count and platelet count), blood pressure, heart rate, oxygen saturation as well as left ventricular ejection fraction (LVEF) and fraction shortening (LVFS) were assessed. RESULTS The prevalence rate of HADT was 66.9% at a high altitude of 4516 m. Compared with those in healthy people at high altitude, some health indicators such as BMI, leukocyte count, neutrophil count, lymphocyte count, platelet count, systolic blood pressure, oxygen saturation, LVEF value and LVFS value were lower but other indicators including the blood viscosity, hematocrit, hemoglobin concentration and heart rate were higher in patients with HADT. CONCLUSIONS The prevalence rate of HADT (66.9%) was high among people moving to a high altitude of 4516 m. Clinical characteristics of HADT were: (1) Impairment of left ventricular systolic function; (2) Immune depression; (3) Microcirculation disturbance; and (4) Decline of hemostasis and coagulation function.