Table 4.

Critical appraisal of 18 studies on the prevalence of AMS

Study and setting	Subjects (n)	Sample design	Sampling frame	Measures	Unbiased assessors	Response rate and refusers	Prevalence rate	Score and limitations
Murdoch et al. (1995) [4] Shyangboche, Asia	154	Guests Mean 45.3 years	Guests staying at hotel	Lake Louise consensus AMS self assessment scoring system	Microbiologist Negative screens not assessed	97.5% Refusers not described	89% of famales 69% of males CI given for OR	Score 5 Poor sample size Negative screens not assessed Refusers not described No CI given
Ziaee et al. (2003) [9] Mount Damavand, Asia	459	Trekkers Mean 31.9 years	Trekkers around Mount Damavand in Iran	Lake Louise consensus AMS self assessment scoring system	Pediatrist Epidemiologist Infectious diseases scientist Negative screens not assessed	100% Refusers not described	60.8% (279/459) No CI given	Score 5 Negative screens not assessed Refusers not described No CI given
Wagner et al. (2008) [10] Mount Whitney, North America	886	Hikers Mean 37.6 years	Trekkers on Mt.Whitney	Lake Louise consensus AMS self assessment scoring system	Six interviewers Negative screens not assessed	100% Refusers not described	42.6% (337/886) No CI given	Score 5 Negative screens not assessed Refusers not described No CI given
Jafarian et al. (2008) [27] Tehran, Asia	90	Volunteers Mean 28.8 years	Individuals in a mountain hotel’s clinic	Lake Louise consensus AMS self assessment scoring system	Neurologist Anesthesiologist Negative screens not assessed	100% Refusers not described	37.8% (34/90) CI given for subgroup	Score 5 Poor sample size Negative screens not assessed Refusers not described
Mairer et al. (2009) [22] Austrian Alps, Europe	422	Recreational hikers Mean 37.4 years	Recreational hikers	Lake Louise consensus AMS self assessment scoring system	Medical researcher Negative screens not assessed	90% Refusers described	16.6% (70/422) No CI given	Score 6 Negative screens not assessed No CI given
Wu et al. (2010) [28] Lhasa, Asia	222	Passengers Mean 40.4 years	Qinghai–Tibet railroad passengers	Lake Louise consensus AMS self assessment scoring system	Physiological Research Group of the Ministry of Railroad Negative screens not assessed	100% Refusers not described	27.0% (60/222) No CI given	Score 4 Poor sample size Negative screens not assessed Refusers not described No CI given
Mairer et al. (2010) [29] Alps, Europe	155	Mountaineers Mean 34.7 years (group 1) Mean 36.8 years (group 2)	Trekkers in both the Eastern and Western Alps	Lake Louise consensus AMS self assessment scoring system	Sport Scientists Medical researchers Negative screens not assessed	100% Refusers described	37.4% (58/155) No CI given	Score 5 Poor sample size Negative screens not assessed No CI given
Wang et al. (2010) [11] Jade Mountain, Asia	1066	Hikers Mean 40.2 years	Trekkers visiting Paiyun Lodge on Jade Mountain	Lake Louise consensus AMS self assessment scoring system	Health workers Medical researchers and doctors Negative screens not assessed	100% Refusers not described	36.0% (384/1066) No CI given	Score 5 Negative screens not assessed Refusers not described No CI given
Modesti et al. (2011) [8] Mount Everest Base Camp, Asia	47	Volunteers Mean 40 years	Recruited volunteers	Lake Louise consensus AMS self assessment scoring system	Medical researchers, doctors statistician Negative screens assessed	100% Refusers not described	34.0% (16/47) No CI given	Score 5 Poor sample size Refusers not described No CI given
Chen et al. (2012) [23] Jade Mountain, Asia	787	Random sample Hikers Mean 42 years	Trekkers on Jade Mountain	Lake Louise consensus AMS self assessment scoring system	Doctors, Health Scientists Negative screens not assessed	100% Refusers not described	32.8% (258/787) No CI given	Score 5 Negative screens not assessed Refusers not described No CI given
Maclnnis et al. (2013) [30] Gosainkunda,Asia	491	Pilgrims Mean 36.7 years	Pilgrims travel to the Janai Purnima festival in Gosainkunda, Nepal (4380 m)	Lake Louise consensus AMS self assessment scoring system	medical student or intern Negative screens not assessed	100% Refusers not described	34.0% (167/491) CI given for RR	Score 6 Negative screens not assessed Refusers not described
Mandolesi et al. (2014) [31] Mount Rosa, Europe	60	Mountaineers Mean 36.4 years	Recruited Mountaineers	Lake Louise consensus AMS self assessment scoring system	Medical researchers Negative screens not assessed	100% Refusers not described	40.0% (24/60) No CI given	Score 4 Poor sample size Negative screens not assessed Refusers not described No CI given
Hsu et al. (2015) [32] Jiaming Lake, Asia	91	Mountaineers Mean 19.8 years	Mountaineers climbing to Jiaming Lake in Taiwan	Lake Louise consensus AMS self assessment scoring system	Three trained emergency physicians Negative screens not assessed	100% Refusers not described	20.9% (19/91) No CI given	Score 4 Poor sample size Negative screens not assessed Refusers not described No CI given
Ren et al.(2015) [33] Lhasa, Asia	80	Volunteers Mean 38.4 years	Recruited volunteers	Lake Louise consensus AMS self assessment scoring system	Medical researcher Negative screens not assessed	100% Refusers not described	43.8% (35/80) No CI given	Score 4 Poor sample size Negative screens not assessed Refusers not described No CI given
Horiuchi et al. (2016) [34] Mount Fuji	345	Climbers Mean 36.1 years	Climbers on Mt.Fuji	Lake Louise consensus AMS self assessment scoring system	Medical researchers Negative screens assessed	88.9% Refusers not described	29.5% (98/345) No CI given	Score 5 Poor response rate Refusers not described No CI given
Sánchez-Mascuñano et al. (2017) [35] Spain, Europe	302	Travellers Mean 37.7 years	Travellers in Barcelona,Spain	Lake Louise consensus AMS self assessment scoring system	Trained medical doctor Negative screens not assessed	92.4% Refusers described	25.8% (78/302) 95% CI 20.9–30.8	Score 7 Negative screens not assessed
Horiuchi et al. (2018) [12] Mount Fuji, Asia	1932	Climbers Mean 37.4 years	Climbers on Mt.Fuji in Japan	Lake Louise consensus AMS self assessment scoring system	Scientific researcher Negative screens not assessed	100% Refusers not described	31.6% (610/1932) CI given for subgroup	Score 6 Negative screens not assessed Refusers not described
J. Boos et al. (2018) [36] Himalayas, Asia	80	Military servicemen Mean 32.1 years	Dhaulagiri region of the Himalayas	Lake Louise consensus AMS self assessment scoring system AMS-C Scores State-Trait-Anxiety-Score	Medical researchers Negative screens not assessed	100% Refusers not described	47.5% (38/80) CI given for Independent predictors	Score 5 Poor sample size Negative screens not assessed Refusers not described

AMS acute mountain sickness, CI confidence interval, RR relative risks, OR odds ratios. The critical appraisal was used to estimate the quality of the published articles, determine the validity and usefulness of prospective studies and improve the overall quality of the included articles