Low estimated glomerular filtration rate explains the association between hyperhomocysteinemia and in-hospital mortality among patients with ischemic stroke/transient ischemic attack or intracerebral hemorrhage: Results from the Chinese Stroke Center Alliance

Objectives: To investigate the association between hyperhomocysteinemia (HHcy) and in-hospital mortality following ischemic stroke (IS), transient ischemic attack (TIA), or intracerebral hemorrhage (ICH). Methods: Data on patients with ischemic cerebrovascular disease (IS/TIA) or ICH enrolled in the Chinese Stroke Center Alliance (CSCA) from 2015 to 2019 were extracted. Patient characteristics and in-hospital mortality were analyzed and multiple adjusted logistic regression analyses performed to investigate the association between blood tHcy (total homocysteine) and in-hospital mortality in patients with HHcy (tHcy ⩾ 15 µmol) and patients with normohomocysteinemia (nHcy) (tHcy < 15 µmol). Results: A total of 823,622 participants were included. Mean (SD) age was 65.9 (12.1), and 62.5% (n = 514,888) were male. A total of 379,807 (46.0%) patients were identified as having HHcy, and 70,364 (8.5%) patients had an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m 2 . An eGFR < 60 mL/min/1.73 m 2 was the strongest independent risk factor for HHcy in both patients with IS/TIA (adjusted odds ratio (aOR) 2.67, 95% confidence interval (CI): 2.49–2.86), and those with ICH (2.94, 2.46–3.50). On multivariable logistic regression, after adjusting for potential confounding factors, HHcy was associated with in-hospital mortality (aOR: 1.25, 95% CI: 1.13–1.37 for patients with IS/TIA; aOR: 1.40, 95% CI: 1.12–1.76 for patients with ICH). However, after additionally adjusting for eGFR, this association disappeared among patients with both IS/TIA (aOR: 1.09, 95% CI: 0.99–1.20) and those with ICH (aOR: 1.17, 9% CI: 0.96–1.43). Conclusion: HHcy was associated with in-hospital mortality among the patients with IS/TIA or ICH but this association disappeared after controlling for eGFR, suggesting HHcy was acting as a marker of poor renal function which itself was the predictor of poor outcome. Our results suggest the prevention and management of renal impairment may be an important measure in the reduction of mortality in patients with HHcy after IS/TIA or ICH.