Kidney Week

Abstract: TH-PO667

Variation in Hemoglobin Distribution in Patients With CKD: The International Network of CKD Cohorts (iNET-CKD)

Session Information

• Anemia and Iron Metabolism
  November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Anemia and Iron Metabolism

• 200 Anemia and Iron Metabolism

Authors

• Canney, Mark, Ottawa Hospital Research Institute Clinical Epidemiology Program, Ottawa, Ontario, Canada

Mark Canney,

• Induruwage, Dilshani, BC Provincial Renal Agency, Vancouver, British Columbia, Canada

Dilshani Induruwage,

• Tang, Mila, BC Provincial Renal Agency, Vancouver, British Columbia, Canada

Mila Tang,

• Er, Lee, BC Provincial Renal Agency, Vancouver, British Columbia, Canada

Lee Er,

• Zhao, Yinshan, The University of British Columbia, Vancouver, British Columbia, Canada

Yinshan Zhao,

• Alencar de Pinho, Natalia, Centre de Recherche en Epidemiologie et Sante des Populations, Villejuif, Île-de-France, France

Natalia Alencar de Pinho,

• Stengel, Benedicte, Centre de Recherche en Epidemiologie et Sante des Populations, Villejuif, Île-de-France, France

Benedicte Stengel,

• Taal, Maarten W., Royal Derby Hospital, Derby, Derby, United Kingdom

Maarten W. Taal,

• Dionne, Janis M., BC Children's Hospital, Vancouver, British Columbia, Canada

Janis M. Dionne,

• Feldman, Harold I., University of Pennsylvania, Philadelphia, Pennsylvania, United States

Harold I. Feldman,

• Hiemstra, Thomas, GlaxoSmithKline Plc, Brentford, London, United Kingdom

Thomas Hiemstra,

• Richards, Anna, GlaxoSmithKline Plc, Brentford, London, United Kingdom

Anna Richards,

• Djurdjev, Ognjenka, BC Provincial Renal Agency, Vancouver, British Columbia, Canada

Ognjenka Djurdjev,

• Levin, Adeera, The University of British Columbia, Vancouver, British Columbia, Canada

Adeera Levin,

Group or Team Name

• iNET-CKD Investigators

Background

Hemoglobin (Hb) has a narrow target range in patients with CKD but little is known about geographical differences in Hb distribution. The aims of this global collaborative study were to compare the distribution of Hb across international CKD populations and evaluate predictors of Hb.

Methods

Two-stage individual participant data meta-analysis of cross-sectional data from participating iNET-CKD cohorts. Included participants were >18 years with non-dialysis CKD (eGFR <60 mL/min). Using a standardized protocol with harmonized variable definitions, the relationships between candidate predictors and Hb were evaluated in linear regression models and estimates were subsequently pooled in a random effects model.

Results

A total of 54,368 participants from 19 cohorts (median eGFR 17 to 49 mL/min) were included with broad geographic representation. Hb values varied substantially among the cohorts even within strata of eGFR and sex (Figure). Across the eGFR range, women had a lower Hb compared to men; however, these differences were smaller at lower eGFR (mean difference 13.2 g/L (95% CI 10.8-15.6) at eGFR of 60 mL/min versus 5.2 g/L (95% CI 3.5-7.0) at eGFR of 15 mL/min, p<0.001 for interaction). In a multivariable model, lower eGFR, female sex, older age, lower body mass index and diabetic kidney disease were independent predictors of a lower Hb value, but this only explained a minority of variance in Hb (median R² of 21% [range 7 to 44%] across the cohorts).

Conclusion

There are substantial regional differences in Hb distribution among individuals with CKD. The majority of variance in Hb is unexplained by demographics, GFR or comorbidities. A better understanding of international variation in Hb, and the factors that contribute to it, could change the way Hb values are interpreted in CKD.

Funding

• Commercial Support – GSK