| 이장훈, 채성철, 박선희, 강정규, 김나영, 양동헌, 박헌식, 조용근, 전재은, 박의현 |
Background: Higher levels of serum phosphate are associated with major adverse cardiovascular events (MACEs), especially in the setting of overt hyperphosphatemia. However, the prognostic value of admission serum phosphate level on MACEs in patients with acute myocardial infarction (AMI) remains unclear. Methods: Between November 2005 and February 2010, 1,468 patients (976 men; mean age = 64.3 ± 11.8 years-old) were followed up more than 12-month after their AMI and finally analyzed in this study. The 12-month MACEs were defined as death, MI, and revascularizations. Results: During the follow-up, 12-month MACEs and mortality were 16.1% (n=237) and 9.8% (n=143), respectively. Serum phosphate levels were significantly higher in patients with 12-month MACEs (3.96 ±1.64 mg/dL versus 3.37 ± 0.97 mg/dL, p<0.001). Serum phosphate levels were significantly positively correlated with log-transformed serum N-terminal pro-B type natriuretic peptide (NT-proBNP) levels (r=0.320, p <0.001), Log-transformed high sensitivity C-reactive protein (hs-CRP) levels (r=0.189, p <0.001), and serum creatinine levels (r=0.288, p <0.001). In multivariate analysis, admission serum phosphate level (hazard ratio [HR] 1.287, 95% confidence interval [CI] 1.017-1.628, p =0.036) in addition to prior coronary heart disease (HR 2.052, 95% CI 1.100-3.826, p =0.024), log-transformed serum NT-proBNP (HR 1.304, 95% CI 1.050-1.620, p =0.016) were independent prognostic factors for 12-month MACEs after adjustment for confounding variables. In ROC curve, the AUC of serum phosphate for predicting 12-month MACE was 0.616 (sensitivity 31.2%, specificity 90.0%), and optimum cut-off value was 4.3 mg/dL. Patients were categorized into two groups according to best cut-off value of serum phosphate (<4.3mg/dL and ≥4.3mg/dL). Kaplan-Meier survival curve showed that higher levels of serum phosphate (≥4.3mg/dL) were significantly associated with increased risk of 12-month MACEs (37.4% versus 12.8%, p<0.001). Conclusion: Admission serum phosphate level is an independent predictor for 12-month MACE in patients with AMI even after adjustment for confounding variables including serum creatinine, NT-proBNP, and hs-CRP levels. Further studies are required to determine the explanation for the association between phosphate and MACEs.
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