Background: High altitude illnesses (HAI) are a risk factor for any individual who is exposed to a significant increase in altitude. To learn more about the epidemiology of HAI, we sought to determine if health records from a commercial trekking company could provide novel data on the prevalence of HAI, as well as efficacy data regarding common HAI therapeutics.

Methods: Health parameters from 917 tourists ascending Mt. Kilimanjaro over a 10-yr period were analyzed for meaningful data.

Results: Of all subjects, 70% experienced at least one instance of a symptom related to HAI (headache, nausea, vomiting, diarrhea, or loss of appetite) during the trek. Acetazolamide was used at least once by 90% of subjects and, of those who used acetazolamide, 92% began taking it on day 1 of the ascent. Acetazolamide was found to improve oxygen saturation 1.2% above 9842.5 ft (3000 m). Dexamethasone use 12 h prior to ascending above 18,996 ft (5790 m) decreased the probability of a subject exhibiting at least one AMS symptom at that altitude.

Discussion: The prevalence of AMS symptoms was not reduced by taking 2 extra days to reach the summit of Mt. Kilimanjaro. Prophylactic acetazolamide modestly improved oxygen saturation; however, it did not reduce symptoms. Therapeutic dexamethasone, especially at higher altitudes, was effective at reducing symptoms. We conclude that meaningful high altitude physiological data can be obtained from private trekking companies.