Intravenous iron in chronic kidney disease without anaemia but iron deficiency: A scoping review

Table 1 Summary of advantages and disadvantages of oral vs intravenous iron repletion

	Oral iron	Intravenous iron
Advantages	(1) Practicality; (2) Sparing of vascular access; and (3) Less costs	(1) Improved compliance; and (2) Less gastrointestinal side effects
Disadvantages	(1) May be less tolerable due to side effects; and (2) Slower at achieving target levels	(1) Needle phobia; (2) Travel time to hospital; (3) Time off work; (4) Anaphylaxis; and (5) Skin reactions

Table 2 Summary of discussed chronic kidney disease and heart failure trials

Trial	n	Intervention	Primary outcome	Secondary outcome
Iron and heart	54	IV FDI vs placebo in people with CKD stage 3b-5 with ID but not anaemic	Non-significant increase in 6MWT at 1 month (P = 0.736) and 3 months (P = 0.741)	At 1-month, significant change in SF and TSAT (P < 0.001)
Iron and muscle	75	IV FCM vs placebo in people with CKD stage 3-4 with ID but not anaemic	Non-significant increase in 6MWT at 4 weeks (P = 0.261)	At 12 weeks, significant change in SF (P < 0.001), TSAT (P = 0.019) and Hb (P = 0.009)
ExplorIRON-CKD	26	IV FDI vs IV FCM in ND-CKD people with ID with/without anaemia	Significant change in iFGF-23 at 1-2 days favouring FCM (P < 0.001)	Significant improvement in functional status regardless of compound used (P < 0.001)
CONFIRM-HF	304	IV FCM vs placebo in people with chronic HF and ID	Significant change in 6MWT at 24 weeks from baseline (P = 0.002)	Significant improvement in NYHA from weeks 24 (P = 0.004) and onwards (P < 0.001)
FAIR-HF	459	IV FCM vs placebo in people with chronic HF and ID	Significant improvement in patient global assessment and NYHA class at 24 weeks (P < 0.001)	Significant improvement in 6MWT from weeks 4 onwards (P < 0.001)
IRONMAN	1137	Long term effects of IV FDI on cardiovascular events in people with HF	Significant reduction in hospital admissions for HF and cardiovascular death (P = 0.047) after adjusting for COVID-19	Non-significant change in 6MWT at 4 months (P = 0.90) and 20 months (P = 0.068)
AFFIRM-AHF	1132	IV FCM vs placebo in people following an episode of acute HF	Significant reduction in HF hospitalizations and deaths up to 52 weeks (P = 0.024) after adjusting for COVID-19	Significant reduction in cardiovascular hospitalizations and deaths up to 52 weeks (P = 0.024) after adjusting for COVID-19
HEART-FID	3065	IV FCM vs placebo in people with HF and ID following recent HF hospitalization	Non-significant improvement in hospitalization, mortality and 6MWT (P = 0.019)	Non-significant reduction in cardiovascular hospitalizations and death (hazard ratio = 0.93)

NYHA: New York Heart Association; IV: Intravenous; FDI: Ferric derisomaltose; CKD: Chronic kidney disease; ID: Iron deficiency; 6MWT: Six-minute-walk test; SF: Serum ferritin; TSAT: Transferrin saturation; FCM: Ferric carboxy maltose; Hb: Haemoglobin; ND-CKD: Non-dialysis dependent chronic kidney disease; FGF: Fibroblast growth factor; HF: Heart failure; COVID-19: Corona virus disease 2019.