Factors affecting pre-end-stage kidney disease haemoglobin control and outcomes following dialysis initiation: a nationwide study.

BACKGROUND: Attaining the narrow haemoglobin (Hb) range recommended by European Renal Best Practice Guidelines renal anaemia guidelines may be difficult, and whether this leads to better outcomes following dialysis initiation is not known.

METHODS: This was an observational study from the Swedish Renal Registry 2012-16, including all patients with non-dialysis-dependent chronic kidney disease (CKD) initiating renal anaemia treatment. We evaluated factors associated with off-target Hb attainment (<10 and >12 g/dL). For those who initiated dialysis, we explored associations between the pre-end-stage kidney disease (pre-ESKD) time in which Hb was within or above range, and pre-ESKD Erythropoietin Resistance Index (ERI) with the 1-year risk of death or major adverse cardiovascular events + (MACE+).

RESULTS: About 5000 patients initiated anaemia treatment, contributing to 25 431 consecutive visits over time. Patients with polycystic kidney disease, diabetic nephropathy and nephrosclerosis, with recent bleeding/transfusion, with higher C-reactive protein or abnormal phosphate had higher odds of maintaining Hb below range. Conversely, patients with older age, CKD Stages 3b-4, pyelonephritis, kidney transplant, iron medication, higher ESA doses or abnormal serum calcium and albumin had higher odds of maintaining Hb above range. A total of 1361 patients initiated dialysis, among whom 220 deaths and 453 MACE+ occurred. A greater time spent with a pre-ESKD Hb >12 g/dL was associated with a lower risk of MACE+ (hazard ratio = 0.76; 95% confidence interval 0.61-0.94) after dialysis initiation, and a lower pre-ESKD Erythropoietin Resistance Index (ERI) was associated with improved survival (1.39; 1.02-1.90).

CONCLUSIONS: Our study identified populations that require additional efforts to control their Hb. Our outcome analysis supports the value of pre-ESKD anaemia care while illustrating the problems of ESA hyporesponsiveness in clinical practice.