. 2020 Sep 18;30(2):59–69. doi: 10.1097/CRD.0000000000000356

TABLE 2.

Levels of Evidence

Level	Description	Results
1A	Systematic review of RCTs	Two reviews with metaanalysis were identified: • One on effect of anakinra on colchicine-resistant and steroid-dependent RP • One on impact of colchicine on pericarditis and postpericardiotomy syndrome^17,18
1B	RCTs	Six placebo-controlled RCTs were identified: • Three compared colchicine with placebo^19–21• Two compared colchicine + aspirin with aspirin alone^22,23• One was a randomized withdrawal study with anakinra²⁴
2A	Systematic review of cohort studies	An initial reporting of the results of this SLR described clinical burden and healthcare resource utilization in RP²⁵
2B/2C	Single-arm trials or RWE studies	One nonrandomized single-center observational study compared colchicine with noncolchicine treatment,²⁶One single-arm prospective open-label study investigated anakinra in patients resistant and intolerant to previous treatment with aspirin and NSAIDs, colchicine, and CS²⁷RWE studies: • Four pediatric (weighted mean age = 13.2 yr)^28–31 • Eight in adult pericarditis patients with information on prescribed first- or second-line treatments (weighted mean age when reported = 50.9 yr)^26,32–38 • Three retrospective studies evaluating second-line CS treatment, typically coadministered with colchicine and NSAIDs^30,33–35• Nine RWE studies with third-line treatment: 7 with anakinra,^37,39–43 2 with azathioprine,^44,45 and 1 with IVIG⁴⁶ • Ten studies with some information about health care resource use (eg, frequency and duration of hospitalizations, procedures, and readmissions),^{5,6,28,29,47–52} including 4 US-focused studies, 2 of which are studies of US commercial claims databases with extensive details regarding resource use and costs,^6,48 1 of which is a study of a US commercial claims database with extensive details on RP epidemiology,⁵¹ and 1 of which analyzes US readmission data after acute pericarditis⁴⁹ • Two studies evaluating long-term outcomes (morbidity and mortality) following an episode of acute pericarditis^53,54

CS indicates corticosteroid; IVIG: intravenous immunoglobulin; NSAID: nonsteroidal antiinflammatory drug; RCT: randomized controlled trial; RP: recurrent pericarditis; RWE: real-world evidence; SLR: systematic literature review; US: United States