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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
  • Induruwage, Dilshani, BC Provincial Renal Agency, Vancouver, British Columbia, Canada
  • Tang, Mila, BC Provincial Renal Agency, Vancouver, British Columbia, Canada
  • Er, Lee, BC Provincial Renal Agency, Vancouver, British Columbia, Canada
  • Zhao, Yinshan, The University of British Columbia, Vancouver, British Columbia, Canada
  • Alencar de Pinho, Natalia, Centre de Recherche en Epidemiologie et Sante des Populations, Villejuif, Île-de-France, France
  • Stengel, Benedicte, Centre de Recherche en Epidemiologie et Sante des Populations, Villejuif, Île-de-France, France
  • Taal, Maarten W., Royal Derby Hospital, Derby, Derby, United Kingdom
  • Dionne, Janis M., BC Children's Hospital, Vancouver, British Columbia, Canada
  • Feldman, Harold I., University of Pennsylvania, Philadelphia, Pennsylvania, United States
  • Hiemstra, Thomas, GlaxoSmithKline Plc, Brentford, London, United Kingdom
  • Richards, Anna, GlaxoSmithKline Plc, Brentford, London, United Kingdom
  • Djurdjev, Ognjenka, BC Provincial Renal Agency, Vancouver, British Columbia, Canada
  • Levin, Adeera, The University of British Columbia, Vancouver, British Columbia, Canada

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