Incidence and clinical characteristics of cardiac amyloidosis in Tuscany and Umbria

Abstract Background Recent advances in imaging and increased disease awareness have led to a significant rise in newly diagnosed cases of cardiac amyloidosis (CA) over the past decade. However, there remains a lack of epidemiological data regarding the true incidence of the disease. Purpose To determine the incidence and clinical characteristics of newly diagnosed cases of CA in a large Italian population. Methods Subjects with suspected CA underwent diagnostic work-up in 20 Centers in Tuscany and Umbria regions within the Cardiac Amyloidosis RegistRY (CARRY), between January 1st 2022 and December 31st 2022. Results A total of 551 subjects were enrolled in the registry, with complete data on the final diagnosis available for 448 individuals. CA was diagnosed in 179 patients (40%), with 28 (16%) classified as light chain CA (AL-CA), 114 (64%) wild-type transthyretin CA (ATTR-CA), 12 (7%) variant ATTR-CA, and 25 (13%) undetermined CA. Considering a reference population in Tuscany and Umbria in 2022 (4,518,388, according to the Italian National Institute of Statistics), this yields an estimated cumulative incidence of 39.6 cases per million inhabitants per year. Alternative diagnoses in the remaining patients mostly included hypertensive heart disease (n=157, 58%), hypertrophic cardiomyopathy (n=25, 9%), moderate-to-severe valvular heart disease (n=11, 4%), or a mixed phenotype (n=72, 27%). The primary referral pathway for the suspicion of CA was cardiological (n=345, 77%), followed by incidental finding during screening visits (n=58, 13%), and haematology referral (n=33, 7%). Patients with confirmed CA were older (81 [75-85] vs. 77 [72-83] years, p<0.001), and more frequently reported musculoskeletal red flags of CA, such as carpal tunnel syndrome (85 [48%] vs. 53 [20%] years, p<0.001), and spontaneous tendon rupture (39 [22%] vs. 18 [7%] years, p<0.001). Median time to diagnosis from clinical suspicion was 73 (37-140) days for CA and 84 (36-156) days for alternative diagnoses (p=0.564). Conclusions The diagnosis of CA is on the rise globally, with an estimated incidence of 39.6 new cases per million inhabitants per year in two large regions of Italy. These findings should inform policymakers in redefining the status of CA as a rare disease, potentially influencing patient care and treatment costs.