Ginkgo biloba and acetazolamide for acute mountain sickness
http://www.100md.com
《英国医生杂志》
EDITOR—The recruitment of Western trekkers in the prevention of high altitude illness trial (PHAIT) study was based on logistics and practicality. Sherpas and other Nepalis residing in or adjacent to the Everest region and above 2000 m are highly resistant to the effects of altitude and would thus be poor research participants. Although many Nepalis working in the Everest region reside at altitudes below 1500 m (potentially eligible research candidates), a fair proportion live in higher regions that would make some degree of acclimatisation likely.
Furthermore, many lowland dwelling Nepalis working as porters will relocate temporarily for the season to wait for work at the airstrip in Lukla (2500 m), where tourists begin their trek. Many will therefore acclimatise en masse in the first weeks of the season, providing a narrow window for enrolment. One of us (BB) tried in 2001 to study lowland porters as subjects but failed to collect adequate data primarily because of poor enrolment and a high rate of loss to follow up. We agree that more evidence is needed about the epidemiology and treatment of altitude sickness in lowland Nepalis.
Excluding bias in clinical trials conducted in the Everest region is inherently problematic because of logistical issues unique to the area. Healthy vacationing trekkers who decline participation in a clinical trial are often not interested in taking the time to provide further information. The argument against bias in our model stems from the large homogeneous cohort evaluated under strict double blinding and in agreement with CONSORT guidelines, as well as the lack of any differences within groups or in comparing those enrolled with those lost to follow up.1 The failure to collect data on those who chose not to enrol in the trial is a weakness of the PHAIT study and was dealt with in a subsequent clinical trial (B Basnyat and J Gertsch, unpublished data; see full reply on bmj.com).
Given these data, we are confident that the PHAIT study is a fair and convincing test of ginkgo's efficacy under the conditions tested.
Jeffrey H Gertsch, resident physician
Department of Internal Medicine, Maricopa Medical Center, 2601 E Roosevelt Avenue number O-D-10, Phoenix, AZ 85008, USA jeffgertsch@hotmail.com
Buddha Basnyat, medical director
Himalayan Rescue Association, Nepal International Clinic, GPO Box 3596, Laldurbarmag 47, Kathmandu, Nepal nic@naxal.wlink.com.np
E William Johnson, resident physician
Department of Surgery, University of Washington, Seattle, WA 98195-6410, USA billjohn@hawaii.edu
Peter S Holck, associate professor
Department of Public Health Sciences and Epidemiology, University of Hawaii, Honolulu, HI, USA holck@hawaii.edu
Full reply is available on bmj.com
Competing interests: JHG has been funded by Pharmaton to attend a research symposium and received reimbursement for on-site living costs incurred during the implementation period of the study.
References
Begg C, Cho M, Eastwood S, Horton R, Moher D, Olkin I, et al. Improving the quality of reporting of randomized controlled trials: the CONSORT statement. JAMA 1996;276: 637-9.(Authors' reply)
Furthermore, many lowland dwelling Nepalis working as porters will relocate temporarily for the season to wait for work at the airstrip in Lukla (2500 m), where tourists begin their trek. Many will therefore acclimatise en masse in the first weeks of the season, providing a narrow window for enrolment. One of us (BB) tried in 2001 to study lowland porters as subjects but failed to collect adequate data primarily because of poor enrolment and a high rate of loss to follow up. We agree that more evidence is needed about the epidemiology and treatment of altitude sickness in lowland Nepalis.
Excluding bias in clinical trials conducted in the Everest region is inherently problematic because of logistical issues unique to the area. Healthy vacationing trekkers who decline participation in a clinical trial are often not interested in taking the time to provide further information. The argument against bias in our model stems from the large homogeneous cohort evaluated under strict double blinding and in agreement with CONSORT guidelines, as well as the lack of any differences within groups or in comparing those enrolled with those lost to follow up.1 The failure to collect data on those who chose not to enrol in the trial is a weakness of the PHAIT study and was dealt with in a subsequent clinical trial (B Basnyat and J Gertsch, unpublished data; see full reply on bmj.com).
Given these data, we are confident that the PHAIT study is a fair and convincing test of ginkgo's efficacy under the conditions tested.
Jeffrey H Gertsch, resident physician
Department of Internal Medicine, Maricopa Medical Center, 2601 E Roosevelt Avenue number O-D-10, Phoenix, AZ 85008, USA jeffgertsch@hotmail.com
Buddha Basnyat, medical director
Himalayan Rescue Association, Nepal International Clinic, GPO Box 3596, Laldurbarmag 47, Kathmandu, Nepal nic@naxal.wlink.com.np
E William Johnson, resident physician
Department of Surgery, University of Washington, Seattle, WA 98195-6410, USA billjohn@hawaii.edu
Peter S Holck, associate professor
Department of Public Health Sciences and Epidemiology, University of Hawaii, Honolulu, HI, USA holck@hawaii.edu
Full reply is available on bmj.com
Competing interests: JHG has been funded by Pharmaton to attend a research symposium and received reimbursement for on-site living costs incurred during the implementation period of the study.
References
Begg C, Cho M, Eastwood S, Horton R, Moher D, Olkin I, et al. Improving the quality of reporting of randomized controlled trials: the CONSORT statement. JAMA 1996;276: 637-9.(Authors' reply)