Identification and Characterization of Trajectories of Renal Function Decline After Heart Transplantation

Abstract

<h3>Purpose</h3> Renal function in heart transplant (HT) recipients usually decreases progressively over time. However, the rate of decline may be highly variable among patients. A variety of mechanisms may be involved with the different progression patterns, with modifiable factors associated with the evolution of the disease. We aimed to identify subgroups of renal function trajectories in HT recipients. <h3>Methods</h3> Glomerular filtration rate was estimated (eGFR) using the CKD-EPI equation, from immediate post HT. The latent class linear mixed model was used to identify subgroups of eGFR trajectories, and patient characteristics were compared between these subgroups. <h3>Results</h3> We identified six distinct trajectories of eGFR among 166 cohort members over 9 [6,14] years follow up (Fig. 1A). The model adequately separated the trajectories, showing a discrimination probability of 0.82 -0.97. Most patients had persistently low levels of eGFR<50 ml/min/1.73m² (34%, Group 5) or experienced a slow decline of eGFR from levels of ∼70 ml/min/1.73m², within the first year, followed by eGFR stabilization (35%, Group 3). Two groups had a strong decline of eGFR within the first year, from different levels of eGFR (80 vs 120 ml/min/1.73m²; Group 4 vs 1), followed either by a progressive slow decline (13%, Group 4) or by eGFR stabilization (5%, Group 1). A further 8% of patients had accelerated loss of eGFR from ∼60 ml/min/1.73m² (Group 6). Finally, 5% experienced an accelerated increase in eGFR from levels of ∼50 ml/min/1.73m² (Group 2). Patients with progressive loss of eGFR (Groups 4,5 & 6) were older with frequent comorbidities. Multivariable analysis showed older recipient age as the stronger independent predictor for progressive loss of eGFR over time (OR 1.29, p=0.01; Fig. 1B). <h3>Conclusion</h3> We identified six clinically relevant subgroups of renal function trajectories. These different progression trajectories of eGFR among HT recipients can serve to investigate modifiable risk factors for renal function deterioration.