Abstract 2988: Low-Grade Inflammation is a Risk Factor for Clinical Stroke Events in Addition to Silent Cerebral Infarcts in Japanese Older Hypertensives: The Jichi Medical School ABPM Study, Wave 1
Background: High-sensitivity C-reactive protein (hsCRP), a marker of inflammation, is associated with hypertensive target organ damage and cerebrovascular events even in the general Japanese population who have lower hsCRP level than Western countries. The additional risk of hsCRP on silent cerebral infarcts (SCIs) to predict clinical stroke events remains unclear in older Japanese hypertensives.
Methods: We conducted brain magnetic resonance imaging and measured hsCRP in 514 older Japanese hypertensives (clinic BP ≥ 140/90mmHg, age ≥ 50 years old) who were enrolled in the Jichi Medical School ABPM Study, wave 1. They were followed up for an average of 41 months (1– 68 months, 1751 person-year) and the incidence of clinical stroke events was evaluated.
Results: Mean age was 72.3 ± 8.7 years (191 men and 323 women) and the median hsCRP level was 0.21 mg/L (75 percentile 0.43 mg/L). The subjects with SCIs (n = 257) had a higher hsCRP level than those without SCIs (geometric mean hsCRP [SD range]; 0.19 [0.18 – 0.21] vs. 0.14 [0.13– 0.16] mg/L, P = 0.006) even after adjustment for the confounding factors. In a Cox regression analysis, the risks for clinical stroke events were higher in patients with above-median hsCRP level (≥ 0.21 mg/L) than those with below-median hsCRP level (hazard ratio [HR] 2.50, 95% confidence interval [CI] 1.24–5.00, P = 0.01), and higher in those with SCIs than those without SCI (HR 4.60, 95%CI 1.91–11.03, P = 0.001) independently of significant covariates such as age, smoking, antihypertensive medication use. The hazard risks of clinical stroke events in the patients with above-median hsCRP level and SCIs were 7.32 times higher than the patients with above-median hsCRP level without SCIs (95%CI 2.17–24.76, P = 0.001), 6.58 times higher than those with below-median hsCRP level and SCIs (95%CI 2.00–21.74, P = 0.002), and 2.98 times higher than those with above-median hsCRP level without SCIs (95%CI 1.35– 6.58, P = 0.007).
Conclusion: hsCRP is an additive risk factor for clinical stroke events in addition to silent cerebral infarcts in Japanese older hypertensives, indicating that a risk for clinical stroke events increase with preexisting hypertensive target organ damage and ongoing low-grade inflammation.