Amyloid cardiomyopathy in a large integrated health care system

Abstract

Background: Light Chain (AL) and transthyretin (ATTR) amyloidosis are the most common forms of amyloid cardiomyopathy. Population based studies describing the epidemiology and clinical features of amyloid cardiomyopathy are often based in tertiary medical centers and thus may be limited by referral bias.

Methods and results: We performed a cohort study of 198 patients diagnosed and treated in the Kaiser Permanente Northern California health care system who had a confirmed diagnosis of cardiac amyloidosis between 2001 and 2016. Associations between demographic, clinical, laboratory and imaging data and patient outcomes were quantified using multivariable Cox proportional hazard models for both the AL and ATTR groups. The average length of follow up was 2.8 years (SD 2.9 years) and overall survival was 69.1 percent at one year and 35.4 percent at five years. In the AL group, lower left ventricular ejection fraction (HR 1.33 per 5-point decrease, P < .001), coronary artery disease (HR 3.56, P < .001), and diabetes mellitus (HR 3.19, P < .001) were associated with all-cause mortality. Increasing age at the time of diagnosis with associated with higher all-cause mortality in both the AL and ATTR groups. Higher levels of B-type natriuretic peptide were associated with all-cause mortality in both groups: Top quartile BNP HR 6.17, P < .001 for AL and HR 8.16, P = .002 for ATTR.

Conclusions: This study describes a large cohort of patients with amyloid cardiomyopathy derived from a community based, integrated healthcare system and describes demographic, clinical, and laboratory characteristics associated with mortality and heart failure hospitalization. In this population, coronary artery disease, diabetes mellitus, and high BNP levels were strongly associated with mortality.