Prevalence and risk factors of stroke in high-altitude areas: a systematic review and meta-analysis

Objective: The primary objective of this study is to investigate the prevalence and risk factors of stroke in high-altitude areas through a comprehensive systematic review and meta-analysis.

Design: This study adopts a systematic review and meta-analysis design.

Data sources: A thorough search was conducted on databases including PubMed, Web of Science, Embase, Cochrane Library, MEDLINE and SCOPUS, covering the period up to June 2023.

Eligibility criteria: Studies reporting the prevalence of stroke in high-altitude areas and exploring related risk factors were included, regardless of whether they involved clinical samples or the general population. Studies with incomplete, outdated or duplicate data were excluded.

Data extraction and synthesis: We performed eligibility screening, data extraction and quality evaluation of the retrieved articles. Meta-analysis was employed to estimate the prevalence and risk factors of stroke in high-altitude areas. The Newcastle-Ottawa Scale was used to assess the risk of bias.

Results: A total of 17 studies encompassing 8 566 042 participants from four continents were included, with altitudes ranging from 1500 m to nearly 5000 m. The pooled prevalence of stroke in high-altitude areas was found to be 0.5% (95% CI 0.3%-7%). Notably, the prevalence was higher in clinical samples (1.2%; 0.4%-2.5%) compared with the general population (0.3%; 95% CI 0.1%-0.6%). When considering geographic regions, the aggregated data indicated that stroke prevalence in the Eurasia plate was 0.3% (0.2%-0.4%), while in the American region, it was 0.8% (0.4%-1.3%). Age (OR, 14.891), gender (OR, 1.289), hypertension (OR, 3.158) and obesity (OR, 1.502) were identified as significant risk factors for stroke in high-altitude areas.

Conclusions: The findings of this study provide insights into the pooled prevalence of stroke in high-altitude areas, highlighting variations based on geographic regions and sampling type. Moreover, age, gender, hypertension and obesity were found to be associated with the occurrence of stroke.

Prospero registration number: CRD42022381541.