From transthyretin cardiac amyloidosis diagnosis to tafamidis treatment: Association of drop-off with patient sociodemographic characteristics.

ABSTRACT

DISCLAIMER In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. PURPOSE: Compared to estimated population prevalence rates, relatively few patients at risk are diagnosed with and treated for transthyretin cardiac amyloidosis (ATTR-CA). Where along the clinical pathway patient drop-off occurs, as well as the association of drop-off with patient sociodemographic characteristics, remains unknown. METHODS: Using data from a healthcare system-wide cardiovascular imaging repository and specialty pharmacy, we characterized the clinical pathway from diagnosis with pyrophosphate scintigraphy (PYP) to tafamidis prescription, initiation, and adherence. Standardized differences (d values of ≥0.20, indicating at least a small effect size) were used to compare sociodemographics (age, sex, race, Area Deprivation Index) among patients with PYP-identified ATTR-CA by tafamidis prescription status and among patients prescribed tafamidis by initiation status. Tafamidis adherence was measured with the proportion of days covered (PDC). RESULTS: Of 97 patients with ATTR-CA, 58.8% were prescribed tafamidis, with 80.7% of those initiating therapy. Patients with 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 ≥ 0.30). Adherence was high (PDC of >80%) in 88.4% of those initiating tafamidis. CONCLUSION: These findings highlight the tremendous opportunity for more robust ATTR-CA clinical programs, identifying potential patient subgroups that should be targeted to reduce disparities. For patients diagnosed with ATTR-CA, utilization of a specialty pharmacy process appears to ensure equitable provision of tafamidis therapy.