Amyloid Screening and Treatment Drop Off in Patients with Left Ventricular Hypertrophy: Associations with Patient Socio-demographic Characteristics

Abstract

Background: Compared to estimated population prevalence rates, relatively few patients at risk are ultimately diagnosed with and treated for transthyretin cardiac amyloidosis (ATTR-CA). Where along the clinical imaging and treatment pathway patient drop off occurs, and the association of drop off at each step with patient socio-demographic characteristics remains unknown. Methods: Using data from a healthcare system-wide cardiovascular imaging repository and specialty pharmacy we characterized the multi-level clinical pathway from screening for left ventricular hypertrophy (LVH) with transthoracic echocardiograms (TTE), diagnosis with technetium-99m pyrophosphate scintigraphy (PYP), and tafamidis prescription, initiation, and adherence. Standardized differences (d≥0.20 indicating a small effect size or larger) were used to compare socio-demographics (age, sex, race, national and state Area Deprivation Index) among patients with TTE-identified LVH by PYP referral status, patients with PYP-identified ATTR-CA by tafamidis prescription status, and patients prescribed tafamidis by initiation status. Results: A total of 8575 patients had LVH on TTE, with 1.6% referred for PYP. Of 97 patients with PYP-identified ATTR-CA, 58.8% were prescribed tafamidis, with 80.7% of those initiating therapy. Referral from LVH on TTE to PYP was higher among men, older patients, and those of Black/African American or American Indian/Alaskan Native race (all d's≥0.20). Patients with PYP-identified ATTR-CA prescribed tafamidis were younger than those not prescribed tafamidis (d=-0.30). Utilization of a specialty pharmacy resulted in enrichment of treatment in subgroups traditionally undertreated in cardiovascular medicine, with higher rates of tafamidis initiation among women (100% initiation), patients of Black/African American race (d=0.40), and those living in more economically disadvantaged areas (d's≥0.30). Conclusion: These findings highlight the tremendous opportunity for more robust imaging and clinical ATTR-CA screening programs, including potential patient subgroups that should be targeted to reduce disparities. Among patients diagnosed with ATTR-CA, utilization of a specialty pharmacy process appears to ensure the equitable provision of tafamidis therapy.