Abstract 15393: Cystatin C and Reclassification of Coronary Heart Disease Deaths among Large Multiethnic Nationally Representative Cohort

Abstract

Objective: To evaluate the reclassification properties of Cystatin C (CysC) for coronary heart disease (CHD) mortality among population free of cardiovascular disease (CVD) and diabetes at baseline.

Background: Data evaluating the reclassification properties of CysC are conflicting and not available from large nationally representative cohorts.

Methods: We evaluated 5,316 participants of the third National Health and Nutrition Examination Survey (NHANES) and 3,243 participants of continuous NHANES (1999 to 2002). Adjusted Cox-proportional hazard analyses were used to evaluate the association between CysC and CHD and CVD deaths. Net reclassification indices (NRI) were calculated for models including Framingham Risk Score (FRS) with and without CysC for CHD deaths.

Results: During median follow-up of 13.9 years in NHANES ΙΙΙ and 5.8 years in continuous NHANES, we identified total of 504 CVD and 364 CHD deaths in NHANES 3 and 94 CVD and 41 CHD deaths in continuous NHANES. CysC was a significant predictor of CVD (adjusted hazard ratio (aHR) - 7.48 (95% confidence interval (CI) 3.40-16.5) p<0.001 in NHANES ΙΙΙ and aHR - 7.49 (95% CI 1.52-36.7) p=0.015 in continuous NHANES) and CHD (aHR - 8.65 (95% CI 3.25-22.9) p<0.001 in NHANES ΙΙΙ and aHR - 16.3 (95% CI 3.72-71.6) p=0.001 in continuous NHANES) deaths after adjustments with traditional risk factors, C-reactive protein, estimated glomerular filtration rate and urine albumin-to-creatinine ratio. CysC, when added to FRS, reclassified 19% and 24% of the overall population and 26% and 50% of the intermediate risk population in NHANES ΙΙΙ and continuous NHANES, respectively. Correspondingly, the continuous NRIs were also significant (0.79 for NHANES ΙΙΙ and 1.14 for continuous NHANES, p<0.001).

Conclusion: CysC is a powerful biomarker to predict incident cardiovascular deaths and can significantly help in reclassifying those at intermediate risk of incident CHD deaths.