Physician-authored summaries and commentary on the most important medical research, provided by the NEJM Group, a division of the Massachusetts Medical Society.
© Massachusetts Medical SocietyApril 2025
Residence above 4000 ft (1219 m) elevation did not speed progression of chronic obstructive lung disease.
At high altitude, partial pressure of inspired oxygen drops, leading to decreased arterial oxygen content and triggering a cascade of physiological adaptations. The effect of prolonged exposure to high altitude on patients with chronic obstructive pulmonary disease (COPD) is not well understood.
Researchers used data from an ongoing multicentre prospective cohort study to compare about 1400 patients with COPD living at less than 1000ft (305m) elevation with about 300 living at more than 4000ft (1219m) elevation. Most of the highaltitude group lived in Denver or Salt Lake City; most participants in both groups had lived at these altitudes for at least 10 years.
In analyses adjusted for relevant confounders, patients at high altitude had about 100ft (30.5m) shorter six-minute walk distance and were more likely to use supplemental oxygen (odds ratio, 7.5). Nevertheless, patient-reported symptom burden was similar in both groups.
During a median of three years’ follow up, the groups had similar rates of decline in forced expiratory volume in one second. Patients living at high altitude had higher mortality (hazard ratio, 1.25) during 11 years of observation, but after controlling for air pollution, this association no longer was significant.
Comment: In my practice in Denver (elevation, 5280ft [1610m]), patients with COPD sometimes ask whether they should move to a lower altitude; this study helps me answer them. Residence at high altitude was associated with greater need for supplemental oxygen and lower exercise capacity, but it did not appear to affect symptom burden or lung function. Controlling for air quality attenuated the effect of altitude on mortality, leading the authors to speculate, ‘the impact of air pollution ... on outcomes in COPD may be more significant than high altitude itself.’
Molly S. Brett, MD, Assistant Professor of Clinical Medicine, University of Colorado School of Medicine; Primary Care Physician, Rocky Mountain Regional VA Medical Center, Aurora, USA.
Suri R, et al. The effect of chronic altitude exposure on chronic obstructive pulmonary disease outcomes in the SPIROMICS cohort: an observational cohort study. Am J Respir Crit Care Med 2024; 210: 1210-1218.
This summary is taken from the following Journal Watch titles: General Medicine, Ambulatory Medicine.