Coronary artery calcium and cystatin C for risk stratification of MACCEs and all‐cause death in symptomatic patients

OBJECTIVES: The aim of this study was to examine the independent and joint associations of baseline coronary artery calcium score (CACS) and cystatin C (Cys‐C) with the risk of major adverse cardiac and cerebrovascular events (MACCEs) and all‐cause death in symptomatic populations. METHODS: The study included 7140 patients with symptom of chest pain who underwent cardiac computerized tomography examinations to measure CACS. All of them had serum Cys‐C results. Endpoints were set for MACCEs and all‐cause death events. RESULTS: A total of 7140 participants were followed for a median of 1106 days. A total of 305 patients had experienced MACCEs and 191 patients had experienced all‐cause death. CACS ≥ 100 and Cys‐C ≥ 0.995 mg/L were independently associated with an increased risk of MACCEs (adjusted hazard ratio [HR]: 1.46; 95% confidence interval [CI]: 1.15–1.85; p = .002 and adjusted HR: 1.57; 95% CI: 1.24–2.00; p < .001, respectively). Compared with CACS < 100 and Cys‐C < 0.995 mg/L patients, CACS ≥ 100 and Cys‐C ≥ 0.995 mg/L patients had the highest risk of MACCEs and all‐cause death (adjusted HR: 2.33; 95% CI: 1.64–3.29; p < .001 and adjusted HR: 2.85; 95% CI: 1.79–4.55; p < .001, respectively). Even in patients with CACS < 100, Cys‐C ≥ 0.995 mg/L was also associated with a higher risk of MACCEs and all‐cause death than Cys‐C < 0.995 mg/L (adjusted HR: 1.76; p = .003 and adjusted HR: 2.02; p = .007, respectively). CONCLUSIONS: The combined stratification of CACS and Cys‐C showed an incremental risk of MACCEs and all‐cause death, reflecting complementary prognostic value. Our results support the combination of the two indicators for risk stratification and event prediction.