Co-occurrence patterns and modifiable risk factors of intracerebral hemorrhage and hypertensive heart disease in adults aged 35 and older: a cross-sectional spatial analysis

Background Intracerebral hemorrhage (ICH) and hypertensive heart disease (HHD) are major contributors to global mortality and disability. While both conditions share common risk profiles, most existing studies have examined them in isolation, limiting understanding of their co-occurrence patterns and shared determinants. This study aimed to systematically assess the global co-burden of ICH and HHD in adults aged ≥35 years, identify their shared and distinct risk factors, and develop an integrated risk index to inform comprehensive prevention strategies. Methods Data were obtained from the Global Burden of Disease (GBD) 2021 study for populations aged 35 and older across 204 countries and territories. We analyzed age-standardized prevalence (ASPR) and disability-adjusted life years (DALYs) for ICH and HHD, standardized using the GBD global reference population. Based on the quartile distribution of these metrics, countries were categorized as ICH-dominant, HHD-dominant, or consistent. Machine learning models and negative binomial regression identified comorbidity-associated risk factors. Sequential population attributable fractions and composite risk indices were computed to assess the burden attributable to selected risk factors. Results Global burden analysis revealed significant disparities, with low-SDI regions bearing a disproportionately higher burden. Classification based on DALYs identified 37 countries as ICH-dominant, 30 as HHD-dominant, and 137 as consistent. ASPR-based classification yielded 46 ICH-dominant, 50 HHD-dominant, and 108 consistent countries, indicating a metric-dependent divergence. Risk factor analysis identified four key drivers for DALYs: iron deficiency, high-sodium diet, low calcium diet, and low polyunsaturated fatty acids intake. For ASPR, low bone mineral density was a shared factor for both diseases, while iron deficiency was specific to ICH. The sequential PAF of these risk factors accounted for 77.64% of global ICH DALYs and 29.87% of HHD DALYs, and 28.85% of ICH ASPR and 7.66% of HHD ASPR. The weighted composite risk index further confirmed substantial geographical heterogeneity in the co-burden.