Clinical outcomes of isolated versus systemic cardiac sarcoidosis: a systematic review and meta-analysis

Isolated cardiac sarcoidosis (ICS) is characterized by a lack of the apparent extra-cardiac involvement seen in systemic cardiac sarcoidosis (SCS) and is being increasingly recognized as a distinct clinical phenotype of cardiac sarcoidosis. This systematic review and meta-analysis pooled data from published literature to assess any differences in outcomes of ICS vs. SCS patients.

Studies were identified from PubMed/Medline, Embase, and the Cochrane Library. Risk ratios were calculated using the Mantel-Haenszel method in a random effects model. Heterogeneity was assessed using the Higgins I ² statistic. Leave-one-out sensitivity analysis was also performed. The primary outcome was a composite of MACE, including cardiac death, ventricular arrhythmias, or hospitalization for heart failure. The secondary outcomes included sudden cardiac death, arrhythmias, and heart-failure-related hospitalizations.

The analysis included 7 studies and 918 CS patients (28.9% ICS and 71.1% SCS). Increased risk for arrhythmias (RR = 3.06, 95% CI: 0.98 to 9.55, p = 0.05, I ² = 67%) in patients with ICS compared to SCS was observed. No significant difference was observed for composite outcome (RR = 1.43, 95% CI: 0.93 to 2.18, p = 0.10, I ² = 0%), HF-related hospitalizations (RR = 6.83, 95% CI: 0.47 to 100.33, p = 0.16, I ² = 80%), or cardiac death (RR = 1.85, 95% CI: 0.49 to 7.08, p = 0.37, I ² = 0%) between the two groups.

Although ICS patients were more likely to experience arrhythmias, no significant difference was observed between ICS and SCS patients for composite outcome, cardiac death, or hospitalizations due to heart failure.