Assessment of Acute Mountain Sickness: Comparing the Chinese AMS Score to the Lake Louise Score

Abstract

Wu, Yu, Wenqi Zhao, Bao Liu, Jianyang Zhang, Zhifeng Zhong, Simin Zhou, Jiaxin Xie, Yuqi Gao, Peng Li, and Jian Chen. Assessment of Acute Mountain Sickness: Comparing the Chinese Ams Score to the Lake Louise Score. High Alt Med Biol 25:164–173, 2024.

Objective:

To compare the ability of the Chinese AMS Score (CAS) to detect acute mountain sickness (AMS) using the 2018 version of the Lake Louise Score (LLS) as reference.

Methods:

After flying from Chengdu (altitude: 500 m) to Lhasa (3,658 m), 2,486 young men completed a questionnaire. The questionnaire contained LLS and CAS items. An LLS ≥3 and/or a CAS ≥cutoff were used as the criteria for AMS. Hierarchical cluster analysis and two-step cluster analysis were used to investigate relationships between the symptoms.

Results:

AMS incidence rates were 33.8% (n = 840) with the LLS and 59.3% (n = 1,473) with the CAS (χ² = 872.5, p < 0.001). The LLS and CAS had a linear relationship (orthogonal regression, Pearson r = 0.91, p < 0.001). With the LLS as the standard, the CAS had high diagnostic accuracy (area under the curve = 0.95, 95% confidence interval: 0.94–0.96). However, with the CAS, 25.5% (n = 633) more participants were labeled as having AMS than with the LLS (false positives). Two clusters were identified: one with headache only (419 participants, 66.2%) and one without headache but with other symptoms (214 participants, 33.8%). Reducing the weight of headache in the CAS allowed to align CAS and LLS.

Conclusion:

In comparison to the LLS, the CAS has a sensitivity close to 100% but lacks specificity given the high rate of false positives. The different weight of headaches may be the main reason for the discrepancy.