30-Year Trends in the Incidence, Characteristics, and Outcome of Cardiac Sarcoidosis in a Nationwide Cohort

Abstract

Background Cardiac sarcoidosis (CS) is a rare but potentially fatal inflammatory cardiomyopathy. Objectives The authors studied temporal changes in the incidence, characteristics, and outcome of CS. Methods A retrospective analysis was made of a 30-year nationwide cohort of CS. Results The cohort comprised 511 patients with a median age of 52 years and female preponderance (69%). Altogether 77, 166, and 268 cases of CS were diagnosed in years 1988 to 2009, 2010 to 2014, and 2015 to 2019, respectively; the 5-year count of 2015 to 2019 was 134-fold the count of 1990 to 1994 (268/2) and 18-fold the count of 2000 to 2004 (268/15). Prior to 2010, compared with the later periods, CS presented more often with ventricular tachycardia/fibrillation (prevalence 36% vs 19% in 2010-2014 and 11% in 2015-2019, P < 0.001), left ventricular ejection fraction <50% (49%, 35%, and 31%; P = 0.010), and elevation of natriuretic peptides (87%, 57%, and 49%; P < 0.001). On magnetic resonance imaging, late gadolinium enhancement involved a median of 15% (IQR: 11%-22%) of left ventricular mass in studies of 1988 to 2009 (n = 16), 15% (IQR: 9%-22%) in studies of 2010 to 2014 (n = 87), and 11% (IQR: 5%-19%) in studies of 2015 to 2019 (n = 150) (P = 0.031). The respective 5-year incidences of the composite of death, heart transplantation, left ventricular–assisted device implantation, or ventricular tachyarrhythmia were 40% (95% CI: 29%-51%), 32% (95% CI: 25%-39%), and 23% (95% CI: 16%-30%) (P = 0.002). The prognostic trend disappeared after adjustment for differences in the presenting phenotype. Conclusions Diagnoses of incident CS have increased exponentially in Finland. Concurrently, the phenotype has turned milder and prognosis better, suggesting detection of CS at an earlier stage of its course.