Abstract WP137: Burden of Stroke Across Altitude Gradients in Peru: A Nationwide Ecological Analysis, 2020–2024

Background: The association between altitude and stroke remains debated in high-altitude countries. Peru’s diverse geography provides a natural setting to explore these patterns. Objective: To characterize stroke burden across altitude gradients in Peru (2020–2024). Methods: Nationwide ecological analysis of adults (≥18 years) with stroke (ICD-10 I60–I64) from SUSALUD. Departmental incidence rates per 100,000 inhabitants were calculated using INEI population data. Population-weighted average altitude was derived for each department. Rates were compared across altitude categories (<500, 500–2499, ≥2500 m) with Kruskal–Wallis tests, and associations with continuous altitude were explored via linear and Poisson regression. Geographic distribution by subtype and healthcare sector was mapped. Results: We identified 9,069 stroke cases. Most occurred in ≥65 years (63.9%) and in males (53.2%). Ischemic stroke was most common (24.6%), followed by hemorrhagic (22.1%), subarachnoid (18.4%), and unspecified (36.5%). The cumulative national rate was 5.7/100,000 (2020–2024). Mean rates: low altitude 8.3, medium 4.8, high 5.2 per 100,000. Differences across categories were not significant (χ 2 = 1.46, p = 0.48). Linear regression suggested a weak, non-significant negative association (β per 1000 m = –0.8, p = 0.15, R 2 = 0.05). Outliers included Callao, San Martín, and Lima. Government hospitals contributed 31.1% of cases, ESSALUD 26.2%, and MINSA 23.8%. Conclusions: Stroke burden in Peru shows no significant differences across altitude gradients. Geographic heterogeneity likely reflects disparities in healthcare access, diagnostic capacity, and vascular risk control rather than altitude alone.