Early high risk period for recurrence after acute pericarditis: insights from temporal pattern analysis

Background Acute pericarditis is characterized by a significant recurrence risk, commonly described as highest within the first two years following the index episode. However, the distribution of recurrence risk within this period remains incompletely characterized. Purpose The purpose of this study was to investigate the timing of pericarditis recurrence after the first documented episode and identify clinical and inflammatory predictors associated with higher recurrence risk. Methods We conducted a single-center observational study including consecutive patients hospitalized with a first episode of acute pericarditis. All patients (n=274) were prospectively monitored for a minimum of 2 years, and the rate and type of relapse was recorded (namely, incessant: persistence or relapse of symptoms during dose tapering within 4 weeks, and, recurrent: relapse after this time period following complete treatment discontinuation). Recurrence timing was categorized per 3-month period for the first year, and recurrence during the second year. Clinical characteristics, inflammatory markers (i.e., c-reactive protein (CRP)), and type of pharmacological treatment during the first episode (e.g., nonsteroidal anti-inflammatory drugs, colchicine and corticosteroids) were analyzed in relation to recurrence. Results Pericarditis relapse (encompassing incessant and recurrent pericarditis) clustered predominantly within the first 3 months after the index episode, accounting for 88.5% of all relapses, with a median time to relapse of 36 days (IQR: 30-60). Incessant pericarditis accounted for 35.7% of all relapse events. More than 93% of relapses occurred within the first 6 months, indicating a markedly higher recurrence risk during this period. Patients experiencing early recurrence had significantly higher peak CRP levels compared to those with later recurrence (p=0.016). Fever at presentation was more frequently observed in early recurrence patients compared to those with recurrence occurring after 3 months (p=0.017). Lastly, corticosteroid use during the initial episode was significantly associated with pericarditis recurrence (p<0.0001). Conclusion Despite existing evidence indicating elevated recurrence risk during the first two years following an acute pericarditis episode, our findings highlight that the highest recurrence burden occurs within the first 3 to 6 months. Elevated CRP and fever at presentation were independently associated with high recurrence risk in the first 3-month period following the initial episode. These results dictate intensified monitoring and careful therapeutic decision-making during the early post-acute phase.