Diagnostic value of high sensitivity C-reactive protein levels in dedifferentiation of stable angina from unstable angina

BACKGROUND: Differentiation of stable angina from unstable angina is important because they need different approaches. Few studies have been conducted to assess the diagnostic value of high sensitive C-reactive protein (hs-CRP) in differentiating these two diseases. This study aimed to evaluate the diagnostic value of hs-CRP levels for differentiating stable angina from unstable angina. METHODS: After signing the consent form, patients with unstable angina who referred to Tohid Hospital emergency in Sanandaj, Iran, and patients with stable angina who referred to the special clinic of the hospital were evaluated. Disease was confirmed by a cardiologist. Morning serum hs-CRP was tested using MONOBIND laboratory kit (USA). Data were analyzed by SPSS using Student's independent t-test, Mann-Whitney U, chi-square, Fisher exact test, and receiver operating characteristic curve. RESULTS: hs-CRP levels in patients with stable angina and unstable angina were 1.6 (± 1.18) and 2.35 (± 1.30) mg/l, respectively (P = 0.025). The hs-CRP level ≥ 2.31 mg/l was the best cut-off point for differentiating stable from unstable angina. At this cut-off point, the sensitivity and specificity were 56% and 73%, respectively. Area under the curve was calculated to be 0.679 (95% confidence interval: 0.54-0.81) (P = 0.017). CONCLUSION: hs-CRP level is helpful for differentiating patients with stable angina from those with unstable angina. It is recommended to consider the hs-CRP level of 2.31 mg/l as the best cut-off point.