Abstract
Background: Patients with transthyretin amyloid cardiomyopathy (ATTR-CM) represent a high-risk heart failure population with continued unmet therapeutic needs. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) improve cardiovascular outcomes in patients with heart failure across the whole spectrum of ejection fraction, and first evidence regarding their safety and effectiveness in patients with ATTR-CM is arising. This study investigates the association between SGLT2i therapy and clinical outcomes in these patients. Methods: This is an analysis of a prospective registry conducted at a referral centre for hypertrophic cardiomyopathies including 116 patients with confirmed ATTR-CM. Fifty-one patients (44%) were treated with SGLT2i while 65 patients (56%) remained SGLT2i-naïve. Results: During a median follow-up of 2.6 (1.7-3.7) years, 38 patients (33%) died, of whom 11 patients (9%) received SGLT2i treatment and 27 patients (23%) were treatment-naïve. SGLT2i therapy was significantly associated with lower mortality (HR 0.457, 95%CI 0.227-0.922, p = 0.029). This association persisted after adjusting for age and sex (HR 0.479, 95%CI 0.235-0.977, p = 0.043) and after additional adjustment for eGFR, NT-proBNP, LVEF, and concomitant therapy with tafamidis (HR 0.328, 95%CI 0.141-0.760, p = 0.009). However, when potential immortal time bias was considered, this association lost statistical significance (HR 1.075, 95%CI 0.524-2.206, p = 0.843). No significant associations between SGLT2i therapy and worsening heart-failure hospitalization or cardiovascular mortality were observed. Conclusions: In crude analysis, SGLT2i therapy associates with better survival in patients with ATTR-CM. However, after adjustment for immortal time, this association becomes statistically insignificant. Hence, to draw final conclusions on the effectiveness of SGLT2i therapy in these patients, a randomized controlled trial is warranted.