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 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: We demonstrate 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 appeared to be protective in this population. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors for any aspect of the submitted work. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the Cleveland Clinic Foundation Institutional Review Board. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data supporting this study are included within the article and/or supporting materials.