Prevalence of chronic obstructive pulmonary disease at high altitude: a systematic review and meta-analysis

Huaiyu Xiong; Qiangru Huang; Chengying He; Tiankui Shuai; Peijing Yan; Lei Zhu; Kehu Yang; Jian Liu

doi:10.7717/peerj.8586

Prevalence of chronic obstructive pulmonary disease at high altitude: a systematic review and meta-analysis

PeerJ. 2020 Apr 3:8:e8586. doi: 10.7717/peerj.8586. eCollection 2020.

Authors

Huaiyu Xiong^{1

2

3}, Qiangru Huang^{1

2

3}, Chengying He², Tiankui Shuai^{1

2

3}, Peijing Yan^{3

4}, Lei Zhu^{1

2}, Kehu Yang^{3

4

5

6}, Jian Liu^{1

2}

Affiliations

¹ The First Clinical Medical College of the First Hospital of Lanzhou University, Lanzhou, China.
² Department of Intensive Care Unit, The First Hospital of Lanzhou University, Lanzhou, China.
³ Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
⁴ Institute of Clinical Research and Evidence Based Medicine, The Gansu Provincial Hospital, Lanzhou, China.
⁵ Evidence Based Social Science Research Center, Lanzhou University, Lanzhou, China.
⁶ Key Laboratory of Evidence Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, China.

Abstract

Background and objective: Recently, several studies have investigated the prevalence of chronic obstructive pulmonary disease (COPD) at high altitude (>1,500 m). However, much remains to be understood about the correlation between altitude and COPD. We aimed to summarize the prevalence of COPD at high-altitudes and find out if altitude could be a risk factor for COPD.

Methods: We searched PubMed/Medline, Cochrane Library, Web of Science, SCOPUS, OVID, Chinese Biomedical Literature Database (CBM) and Embase databases from inception to April 30th, 2019, with no language restriction. We used STATA 14.0 to analyze the extracted data. A random-effect model was used to calculate the combined OR and 95% CI. Heterogeneity was assessed by the I ² statistic versus P-value. We performed a subgroup analysis to analyze possible sources of heterogeneity. The Egger's test and the Begg's test were used to assess any publication bias.

Results: We retrieved 4,574 studies from seven databases and finally included 10 studies (54,578 participants). Males ranged from 18.8% to 49.3% and the population who smoked ranged from 3.3% to 53.3%. The overall prevalence of COPD at high-altitude was 10.0% (95% CI [0.08-0.12], P < 0.001). In a subgroup analysis, based on different regions, the results showed that the prevalence in Asia was higher than that in Europe and America. Seven studies compared the relationship between the prevalence of COPD at high-altitudes and the lowlands. The results showed that altitude was not an independent risk factor for the prevalence of COPD (OR_adj = 1.18, 95% CI [0.85-1.62], P = 0.321). There was no publication bias among the studies.

Conclusions: Our study found a higher prevalence of COPD at high-altitudes than those from average data. However, altitude was not found to be an independent risk factor for developing COPD (PROSPERO Identifier: CRD42019135012).

Keywords: Altitude; COPD; Meta-analysis; Risk factor.

Grants and funding

The authors received no funding for this work.