REN and anemia: Thematic evolution analysis of the author’s keywords showed that the initial stage of investigation on uremic cardiomyopathy was mainly focused on “renin-angiotensin system,” “hypertension,” “parathyroidectomy,” and “erythropoietin,” whereas, the main topics remained “hypertension” and “anemia” in the growing stage, indicating that the understanding on uremic cardiomyopathy was not deepened in this stage.