Incidence of acute mountain sickness in young adults at 3200 meters: comparison of the Lake Louise Scoring and Chinese Scoring Systems

Abstract

The purpose of this study was to compare two scoring systems used for the diagnosis of acute mountain sickness (AMS): the Lake Louise Scoring (AMS-LLS) and the Chinese Scoring Systems (AMS-CSS). In total, 339 healthy young adult volunteers residing at sea level ascended to 3200 m by train and bus over a total journey time of 48 h. All subjects ascended in the same manner and were divided into three groups that were assessed after one (N = 88), two (N = 91), and three (N = 160) nights, respectively, at altitude. The overall incidence of AMS was 17.11% (N = 58) and 29.79% (N = 101) according to the AMS-LLS and AMS-CSS, respectively. Two participants (0.59%) experienced high-altitude pulmonary edema. Both scoring systems showed the highest incidence of AMS after the second night at high altitude. The AMS-CSS and AMS-LLS scores were significantly correlated (Pearson's r = 0.820, P < 0.001). The AMS-CSS identified all AMS subjects diagnosed by the AMS-LLS, and an additional 43 subjects. The dominant symptoms were reduced exercise tolerance (61.7%), fatigue (49.0%), dizziness (28.9%), chest distress (28.3%), and headache (27.4%). Compared with the AMS-LLS, the sensitivity, specificity, and positive and negative predictive values of the AMS-CSS were 100, 84.7, 57.43, and 100%, respectively. There was no relationship between oxygen saturation levels and AMS scores at 3200 m. In summary, the AMS-CSS was similar to AMS-LLS, except that it resulted in more positive diagnoses, and headache did not play a large diagnostic role.