Predictors of Developing Renal Dysfunction Following Diagnosis of Transthyretin Cardiac Amyloidosis

Background In patients with transthyretin cardiac amyloidosis (ATTR-CA), renal dysfunction is a poor prognostic indicator. Limited data are available on variables that portend worsening renal function (wRF) among ATTR-CA patients. Objectives This study assesses which characteristics place patients at higher risk for the development of wRF (defined as a drop of ≥ 10% in GFR) within the first year following diagnosis of ATTR-CA. Methods We included patients with ATTR-CA (n=134) evaluated between 2/2016 and 12/2022 and followed for up to one-year at our amyloid clinic. Patients were stratified into two groups: a group with maintained renal function (mRF) and a group with wRF and compared using appropriate testing. Significant variables in the univariate analysis were included in the multivariable logistic regression model to determine characteristics associated with wRF. Results Within a follow-up period of 326±118 days, the median GFR% change measured -6% [-18%, +8]. About 41.8% (n=56) had wRF, while the remainder had mRF. In addition, in patients with no prior history of CKD, 25.5% developed de-novo CKD. On multivariable logistic regression, only NYHA class ≥III (OR: 3.9, 95% CI [1.6-9.3]), history of IHD (OR:0.3, 95% CI [0.1-0.7]), and receiving SGLT-2i (OR: 0.1, 95% CI [0.02-0.5]) were significant predictors of wRF. Conclusion Our study demonstrated that the development of new or worsening renal dysfunction is common following the diagnosis of ATTR-CA. Additionally, we identified worse NYHA class and no prior history of IHD as significant predictors associated with developing wRF, while receiving SGLT2i therapy appeared to be protective in this population.