Clinical and Radiological Features of COPD Patients Living at ≥3000 m Above Sea Level in the Tibet Plateau

Abstract

Background

COPD at high altitude may have different risk factors and unique clinical and radiological phenotypes. We aimed to investigate the demographic data, clinical and radiological features of COPD patients permanently residing at the Tibet Plateau (≥3000 meters above sea level).

Methods

We conducted an observational cross-sectional study which consecutively enrolled COPD patients visiting the outpatient of Respiratory Medicine at Tibet Autonomous Region People’s Hospital from January 2018 to March 2021. All patients were Tibetan permanent residents aging ≥40 years and met the diagnosis of COPD according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. Data including demographic characteristics, altitude of residence, risk factors, respiratory symptoms, comorbidities and medications, as well as computed tomography (CT) measurements were collected.

Results

Eighty-four patients with definite COPD were enrolled for analysis. Their mean age was 64.7 (±9.1) years. All patients lived at ≥3000 m above sea level and 34.5% of them lived at ≥4000 m. About 8.3% of the patients were current smokers and 44.0% were ex-smokers. Up to 88.1% of the patients reported long-term exposure to indoor biomass fuels. Most of the patients were classified as having mild-to-moderate (GOLD I: 27.4%; GOLD II: 51.2%) COPD, while 89.3% had a CAT score ≥10. Only 36.9% of the patients received regular long-term medications for COPD in the past year, in whom ICS/LABA and oral theophylline were the most common used pharmacological therapy. On CT scanning, the majority of our patients (70.7%) showed no or minimal emphysema, while signs of previous tuberculosis were found in 45.1% of the patients.

Conclusion

COPD patients living at the Tibet Plateau had a heavy respiratory symptom burden, but most of them did not receive adequate pharmacological treatment. Indoor biomass fuel exposure and previous tuberculosis were prevalent, while the emphysema phenotype was less common in this population.

Keywords:

• chronic obstructive pulmonary disease
• high altitude
• phenotype
• computed tomography

Abbreviations

COPD, chronic obstructive pulmonary diseases; GOLD, Global Initiative for Chronic Obstructive Lung Disease; CT, computed tomography; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; BMI, body mass index; BSA, body surface area; CAT, COPD Assessment Test; LAA, low attenuation area; WT, bronchial wall thickness; LA, luminal area (LA); WA, bronchial wall area; TDR, thickness-to-diameter ratio; LABA, long-acting β2 agonist; ICS, inhaled corticosteroids; LAMA, long-acting muscarinic antagonist; SABA, short–acting β-agonist; SAMA, short-acting muscarinic antagonist.

Data Sharing Statement

The data that supports the findings of this study will not be shared openly with other third parties due to contractual statements related to intellectual property, confidentiality, and proprietary rights.

Ethics Approval and Informed Consent

The study protocol was approved by the Independent Ethics Committee of the Peking University Third Hospital (IRB00006761-M2020430) and the Ethics Committee of Tibet Autonomous Region People’s Hospital (ME-TBHP-20-KJ-036). Written informed consents were obtained from the patients or their close relatives. This study was conducted in accordance with the Declaration of Helsinki.

Author Contributions

All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; agreed to submit to the current journal; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest for this work.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [No. 81970041, 82090014, and 81700039] and Capital Health Development Research Project [No. 2020-2Z-40917].