Assessment of Acute Mountain Sickness: How to integrate the advantages of the Lake Louise Score and the Chinese AMS Score

Abstract

Aims: To compare the differences in acute mountain sickness (AMS) incidence between two AMS diagnostic scoring criteria, including the Lake Louise Score and the Chinese AMS Score. Methods: A total of 2486 young men completed questionnaires after flying from Chendu (500 m) to Lasha (3658 m). The AMS incidence was investigated using a questionnaire that contained the scoring criteria for the LLS and CAS. To determine the grouping of all the symptoms on the AMS questionnaire, a systematic cluster analysis and two-step cluster analysis were used to analyse various symptoms and cases separately.Results: The AMS incidence was 37.5% (n = 932) according to the LLS, in which the cut-off point depended on headache and a total score ≥ 3, and 59.3% (n = 1473) according to the CAS, in which the cut-off point depended on headache, vomiting or a total score ≥ 5. The LLS and CAS outcomes had a significant positive correlation (Spearman’s rho = 0.918, P < 0.05) and were moderately consistent (kappa value = 0.488, P < 0.001). The positive AMS incidence determined by the CAS was significantly higher than that by the LLS (P < 0.001). Compared with the LLS, the sensitivity was 100%, the specificity was 65.23%, the positive predictive value was 63.34%, and the negative predictive value was 100% for the CAS in the diagnosis of AMS. The CAS identified all AMS subjects diagnosed by the LLS, and an additional 541 subjects. Of all the symptoms investigated, the dominant symptoms were fatigue (59.3%), dizziness (55.0%), headache (50.6%), chest tightness (40.4%), and shortness of breath (37.2%), and the last two symptoms were not included in the LLS. The cluster analysis show that chest distress, shortness of breath and palpitations were relatively independent of the major symptoms assessed by the LLS. Conclusion: The CAS had testing characteristics for diagnosing AMS similar to those of the Lake Louise Questionnaire Score, and the CAS diagnosed a higher prevalence of AMS than the LLS. It is suggested that chest distress and shortness of breath should be paid adequate attention and taken into account in AMS diagnostic criteria in the next revision to better diagnosis and study AMS.