• Rajat Suri, Daniela Markovic, Han Woo, Mehrdad Arjomandi, R Graham Barr, Russell P Bowler, Gerard Criner, Jeffrey L Curtis, Mark T Dransfield, M Bradley Drummond, Spyridon Fortis, MeiLan K Han, Eric A Hoffman, Robert J Kaner, Joel D Kaufman, Jerry A Krishnan, Fernando J Martinez, Jill Ohar, Victor E Ortega, Robert Paine Iii, Xavier Soler, Prescott G Woodruff, Nadia N Hansel, Christopher B Cooper, Donald P Tashkin, Russell G Buhr, and Igor Z Barjaktarevic.
• University of California San Diego, 8784, Pulmonary, Critical Care, and Sleep Medicine, La Jolla, California, United States; rsuri@health.ucsd.edu.
• Am. J. Respir. Crit. Care Med. 2024 Mar 20.

RationaleIndividuals with COPD have airflow obstruction and maldistribution of ventilation. For those living at high altitude, any gas exchange abnormality is compounded by reduced partial pressures of inspired oxygen.ObjectivesDoes residence at higher-altitude exposure affect COPD outcomes, including lung function, imaging characteristics, symptoms, health status, functional exercise capacity, exacerbations, or mortality?MethodsFrom the SPIROMICS cohort, we identified individuals with COPD living below 1,000 ft (305 m) elevation (n= 1,367) versus above 4,000 ft (1,219 m) elevation (n= 288). Multivariable regression models were used to evaluate associations of exposure to high altitude with COPD-related outcomes.Measurements And Main ResultsLiving at higher altitude was associated with reduced functional exercise capacity as defined by 6MWD (-32.3 m, (-55.7 to -28.6)). There were no differences in patient-reported outcomes as defined by symptoms (CAT, mMRC), or health status (SGRQ). Higher altitude was not associated with a different rate of FEV1 decline. Higher altitude was associated with lower odds of severe exacerbations (IRR 0.65, (0.46 to 0.90)). There were no differences in small airway disease, air trapping, or emphysema. In longitudinal analyses, higher altitude was associated with increased mortality (HR 1.25, (1.0 to 1.55)); however, this association was no longer significant when accounting for air pollution.ConclusionsChronic altitude exposure is associated with reduced functional exercise capacity in individuals with COPD, but this did not translate into differences in symptoms or health status. Additionally, chronic high-altitude exposure did not affect progression of disease as defined by longitudinal changes in spirometry.

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