Serum potassium and high-altitude coronary microvascular disease: a propensity score matched analysis revealing a linear dose-response relationship.

Background: High-altitude exposure precipitates coronary microvascular disease (CMVD), a pathology linked to hypoxia-induced ion channel dysfunction. However, prior observational evidence connecting serum potassium to CMVD resilience is limited by residual confounding, and the precise dose-response trajectory remains unmapped. This study utilized Propensity Score Matching (PSM) to rigorously isolate this association and characterize the dose-response trajectory across the observed physiological range. Methods: We conducted a nested case-control analysis within a high-altitude training cohort. To minimize selection bias, 1:1 PSM was employed to strictly balance covariates-including age, blood pressure, and autonomic nervous regulation-between CMVD cases and controls. The final analytic sample comprised 462 participants (231 pairs). We applied conditional logistic regression and dose-response modeling to evaluate the association between pre-high-altitude serum potassium and CMVD risk. Results: Post-matching analysis confirmed that higher baseline serum potassium was independently associated with a significantly reduced CMVD likelihood. The adjusted odds ratio was 0.18 (95% CI: 0.08-0.42, Conclusion: Higher physiological serum potassium is robustly and linearly associated with reduced likelihood of CMVD under high-altitude hypoxic conditions. These association-based findings suggest the potential value of further investigating whether maintaining higher physiological potassium levels before high-altitude deployment may reduce CMVD risk, moving beyond merely screening for hypokalemia.