Temporal Trends in Hemoglobin, Use of Erythropoiesis Stimulating Agents, and Major Clinical Outcomes in Incident Dialysis Patients in Canada

Abstract

Introduction: Several jurisdictions have adopted a more conservative approach to anemia in patients receiving dialysis amid safety concerns from target hemoglobin studies. It is largely unknown if this has contributed to a change in clinical outcomes. Methods: A national registry was used to identify 35,945 adult patients who initiated and were maintained on dialysis for ≥90 days in Canada from January 2007 to December 2015. Outcomes were ascertained until March 2017 via linkage with hospital discharge diagnoses. Cox proportional hazards models were used to investigate the association between the era of dialysis initiation and the primary composite outcome (acute myocardial infarction [AMI], stroke, or mortality). Results: The mean hemoglobin at dialysis initiation decreased from 102.9 g/l in 2007 to 95.5 g/l in 2015, corresponding with a higher prevalence of hemoglobin <80 g/l (8% to 17%) and a reduction in erythropoiesis stimulating agent (ESA) use (49% to 44%). After multivariable adjustment, Era 3 (2013–2015) was associated with an 8% relative risk reduction in the primary outcome compared with Era 1 (2007–2009) (hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.88–0.96), a 10% relative reduction in mortality (HR 0.90, 95% CI 0.85–0.94) but no significant change in AMI or stroke. In a model without era, neither hemoglobin nor ESA use was an independent predictor of outcome. Conclusion: There have been modest declines in average hemoglobin values and ESA use among incident dialysis patients in Canada with no change in major cardiovascular outcomes. Patient survival has improved over time, likely for reasons other than anemia management.

Keywords

• acute myocardial infarction
• anemia
• dialysis
• erythropoiesis stimulating agent
• mortality
• stroke