Table 2 Characteristics of patients and interventions in each included study
Study | Study population | Exclusion criteria | Doses | Drug administration and assessment of AMS | Age in years (mean ± SD) | BMI (mean ± SD) |
|---|---|---|---|---|---|---|
Zheng et al. | Non-Tibetan healthy young male lowland residents (18–35 years old). | HA (> 2500 m) exposure history in the past year; severe organic diseases; contraindications of budesonide or dexamethasone. | Budesonide: 200 μg per inhalation, bid. Dexamethasone: 4 mg, bid. Placebo. | Drugs started 1 day before ascent and continued for 2 days after high altitude exposure. AMS assessed 4 days after high altitude exposure (2 days after last inhalation) | Budesonide: 20.39 ± 2.40. Dexamethasone : 20.78 ± 2.30. Placebo: 20.52 ± 2.35. | Budesonide: 21.32 ± 2.28. Dexamethasone: 21.13 ± 1.86. Placebo 20.95 ± 1.95. |
Chen et al. | Lowland residents at or below 500 m, healthy, and 18 to 35 years of age. | HA (> 2500 m) exposure history in the past year or organic diseases or psychological or neurological disorders. | Budesonide: 100 μg per inhalation, two inhalations bid. Procaterol: 25 μg bid. Budesonide/formoterol: 160 μg budesonide/4.5 μg formoterol per inhalation, one inhalation, bid. Placebo. | Drugs started 3 days before ascent and stopped after high altitude exposure. AMS assessed 1 day after high altitude exposure (1 day after last inhalation). | Budesonide : 21.85 ± 3.23. Procaterol: 20.30 ± 2.03. Budesonide/formoterol: 20.60 ± 2.76. Placebo: 21.65 ± 3.31 | Budesonide: 20.98 ± 2.21. Procaterol: 21.00 ± 1.44. Budesonide/formoterol: 21.64 ± 1.49. Placebo: 22.15 ± 2.94. |
Berger et al. | Healthy, non-smoker, non-acclimatised lowlanders were included in the study | Spent time at altitudes > 2000 m within the past 4 weeks before the study, took any regular medication | Budesonide 200 μg: bid. Budesonide 800 μg: bid. Placebo. | Drugs started 1 day prior to ascent and continued for 4 days (2 days after high altitude exposure). AMS assessed on last day of inhalation (2 days after high altitude exposure). | Budesonide 200 μg: 38 ± 11. Budesonide 800 μg: 38 ± 11. Placebo: 36 ± 12. | Budesonide 200 μg: 24.0 ± 2.1. Budesonide 800 μg: 22.5 ± 2.2. Placebo: 22.8 ± 2.5. |
Lipman et al. | Healthy, low landers < 1240 m (4,100 ft), able to complete a moderately strenuous hike at high altitude | Younger than 18 years old or over 65, pregnant or considered pregnant, living or sleeping at an altitude of more than 1240 m (4,100 ft) last week, taking diuretics, steroids, acetazolamide or NSAIDs a week before the study, allergy to study drugs or a dangerous condition, which did not allow to travel at high altitude | Placebo. Acetazolamide: 125 mg PO bid. Budesonide: 180 μg per inhalation bid. | Drugs started on morning of ascent day and AMS assessed on evening after high altitude exposure. | Placebo: 32 ± 7. Acetazolamide: 33 ± 9. Budesonide: 33 ± 10. | Placebo: 24 ± 2.6. Acetazolamide: 24.1 ± 1.93. Budesonide: 22.7 ± 2.1. |
Wang et al. | Healthy young male who lived a long term in 2000 m (18–28 years old). | HA (> 2500 m) exposure history in the past year; severe organic diseases or psychological or neurological disorders; contraindications of study drugs; other unsuitable conditions | Ipratropium bromide/salbutamol: 0.5 mg ipratropium bromide/3 mg salbutamol sulfate per inhalation, bid. Budesonide: 2.0 mg per inhalation, bid. Salbutamol sulfate: 5.0 mg per inhalation, bid. Placebo. | Drugs started on day of ascent and continued till high altitude exposure (3 days). AMS assessed after 3 days of high altitude exposure. | Ipratropium bromide/salbutamol: 21.89 ± 2.78. Budesonide: 21.35 ± 3.05. Salbutamol sulfate: 21.25 ± 2.35. Placebo: 22.83 ± 2.74. | Ipratropium bromide/salbutamol: 21.55 ± 1.31. Budesonide: 21.94 ± 2.11. Salbutamol sulfate: 21.40 ± 1.68. Placebo: 21.73 ± 2.25. |