#2770 Evaluation of the effect of IV iron therapy on eGFR and Pro-BNP in patients with chronic kidney disease and heart failure with preserved EF
Authors: Helvacı Özant , Sezenoz Burak , Ay Elif Isil , Yıldırım Saliha , Yasar Emre , Gobut Ozden Seckin , Demirezen Asil , Akcay Omer Faruk , Altok Kadriye , Erten Yasemin , Guz Galip , Derici Ulver 
Published: May 2024

Abstract

Background and Aims
Iron replacement in treating heart failure (HF) is an issue whose importance has been better understood in recent years. Although controversies exist, randomized controlled studies have shown that IV iron treatment reduces mortality and improves symptomatology in heart failure with low EF (HFrEF).
IV iron has not dramatically affected survival in heart failure with preserved EF (HFpEF). However, there is data that it might reduce symptoms and hospitalizations. For patients with chronic kidney disease (CKD) and HF, around 60% of them have HFpEF. Major heart failure and iron studies have often been performed on patients with low EF. Furthermore, in some of these studies, GFR values were not reported, and in the others, GFR was often &gt; 60 ml/minute.
We planned this study to evaluate the effects of IV iron therapy on eGFR and Pro-BNP levels in non-dialysis CKD patients with HFpEF.

Method
This study was conducted between January 2022 and December 2023. Patients with iron deficiency anemia, stage 2-5ND chronic kidney disease, and those with Pro-BNP values of 1000 and above were selected. Two independent cardiologists evaluated them, and the diagnosis of heart failure was confirmed. Patients were given one dose of 500 or 1000 mg of FCM. Control values were obtained at the 1-month follow-up.
Hospitalized or transfused patients, cases with primary hematological disease, and cases with conditions affecting ferritin levels were excluded. Patients whose RAAS blockade, SGLT-2 inhibitor, and diuretic doses were changed, were excluded from the analysis. No patients received ESA or HIF stabilizers.
Demographic and clinical data of the patients were recorded. The patients' creatinine, eGFR, hemoglobin, ferritin, and pro-BNP levels were evaluated before and after iron treatment

Results
Seventy-four patients were recruited. Forty-seven patients were women. The average age was 68 ± 11 years. Forty-eight of the patients had diabetes (64.9%) and 47 (63.5%) had coronary artery disease. The etiology of HFpEF was diastolic heart failure in 45 patients (60%). Other patients had valve disease, HFmEF, HFimpEF, isolated right-sided HF, and mixed types of HFpEF.
After IV iron treatment, an increase of 3 ± 1 ml/min in GFR and 1.1 ± 0.1 g/dL in hemoglobin was detected. ProBNP levels decreased by 46%. All findings were statistically significant. The findings are summarized in Table 1.

Conclusion
The decrease in ProBNP levels was similar to the HFrEF literature. No positive or negative effects of iron on GFR were observed in the REVOKE and FIND-CKD studies, which compared oral and IV iron in CKD patients. The small but significant increase in GFR in our study could be attributed to the improvement of cardiac function. However, the small number of patients and the short follow-up period make it difficult to reach a definitive conclusion on this issue.
We have shown that IV iron treatment significantly reduces Pro-BNP levels in CKD patients with HFpEF. IV iron has no adverse effects on renal function in the short term, and there is little signal of potential positive effects. Longer-term studies, preferably randomized with oral iron, with appropriate sample size, are needed to evaluate how IV iron affects end-points such as HF symptom score, hospitalization, eGFR slope, need for renal replacement, and mortality in this patient group.

Strengths
Well-selected patient group, a high Pro-BNP cut-off point, re-evaluation of each patient by the cardiologists

Limitations
Relatively small cohort, short follow-up period