Prevalence of C-Reactive Protein Elevation and Time Course of Normalization in Acute Pericarditis: Implications for the Diagnosis, Therapy, and Prognosis of Pericarditis

Study Questions:

What is the frequency of high-sensitivity C-reactive protein (hs-CRP) elevation in patients with acute pericarditis; its time course of normalization; and the possible importance for diagnosis, therapy, and prognosis?

Methods:

Two hundred consecutive patients with viral or idiopathic acute pericarditis (mean age, 53 ± 15.5 years; 103 men) were studied from August 2005 to August 2007 in two Italian referral centers. Hs-CRP was determined at presentation and then every week until normalization. Time-to-event distributions were estimated by the Kaplan-Meier method and compared with the log-rank test. The Cox proportional hazards model was used to identify independent risk factors for recurrences.

Results:

Hs-CRP elevation was recorded in 156 of 200 cases (78%) at presentation. Recognized causes of a negative hs-CRP at presentation were early assessment in 15 of 44 cases (34%) and previous anti-inflammatory therapies in 22 of 44 cases (50%). Hs-CRP normalization was achieved with the following time course: 120 of 200 (60%) at week 1, 170 of 200 (85%) at week 2, 190 of 200 (95%) at week 3, and all cases (100%) at week 4. In multivariable analysis, incomplete response to empirical anti-inflammatory therapy at week 1 (hazard ratio [HR], 2.98; 95% confidence interval [CI], 1.80-4.94; p < 0.001), corticosteroid therapy (HR, 2.80; 95% CI, 1.59-4.95; p < 0.001), and the presence of elevated hs-CRP at week 1 (HR, 2.36; 95% CI, 1.32-4.21; p = 0.004) were independent risk factors for recurrence.

Conclusions:

The authors concluded that hs-CRP is elevated at the initial presentation in three of four cases of acute pericarditis, identifies patients at higher risk of recurrence, and could be used to monitor disease activity and select appropriate therapy length.

Perspective:

This study reports that hs-CRP elevation at presentation is common, but not present in all cases of pericarditis. A diagnosis of pericarditis should rely on clinical criteria and not only on CRP elevation, although it may support the clinical suspicion. The study further suggests that persistently elevated hs-CRP may identify patients at higher risk of recurrence, and for patients with elevated hs-CRP, anti-inflammatory therapy should be continued until hs-CRP normalization instead of an empirical length of therapy.

Keywords: Prevalence, Prognosis, C-Reactive Protein, Recurrence, Biomarkers, Risk Factors, Pericarditis


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