Prevalence, spectrum and aetiology of valvular heart disease based on community echocardiographic screening transition from different altitudes in Yunnan, China.

Background: The burden of valvular heart disease (VHD) is rising rapidly globally, accompanied by substantial geographical disparities. Although altitude may influence cardiovascular system, no community-based studies have yet explored altitudinal differences in VHD epidemiology.

Objective: This study aims to investigate the prevalence, spectrum and aetiology of VHD in different altitude areas.

Methods: We conducted two sequential community-based echocardiography screening programmes in Yunnan Province of China and included 5059 eligible participants aged 35 years and older. The multivariable Poisson regression models with robust variance were performed to assess the association of different altitude groups with VHD and its subtypes.

Results: The prevalence of overall VHD, clinically significant VHD and clinically significant regurgitant VHD was 36.7%, 2.5% and 2.4%, respectively. After stratification by altitude, the prevalence of any VHD among participants in the <2000 m, 2000-2499 m, 2500-2999 m and ≥3000 m groups was 30.4%, 40.9%, 35.0% and 44.3%, respectively. The fully adjusted models showed that the prevalence ratios for VHD in the 2000-2499 m, 2500-2999 m and ≥3000 m groups were 1.28 (95% CI 1.15 to 1.42), 1.20 (95% CI 1.02 to 1.41) and 1.34 (95% CI 1.04 to 1.72), compared with the <2000 m group. Clinically significant VHD in the <3000 m altitude group was predominantly degenerative in aetiology, whereas functionality was most prevalent in the ≥3000 m altitude group. Subgroup analysis identified some high-risk populations, including male, minority ethnicity, 60 years and older and high systolic blood pressure.

Conclusions: Adults living at high altitudes have a higher prevalence risk of VHD; significant altitudinal differences exist in the characteristics and aetiology of VHD. The findings could provide insights into primary prevention and early screening for VHD in low- and middle-income countries where a majority of the population lives at high altitudes.