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Abstract: TH-PO770

Mortality Risk According to eGFR and Proteinuria in Persons Older Than 65 Years: Results From a Nationwide Study in Iceland

Session Information

Category: Geriatric Nephrology

  • 1200 Geriatric Nephrology

Authors

  • Jonsson, Arnar Jan, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
  • Lund, Sigrún Helga, deCODE Genetics Inc, Reykjavik, Capital, Iceland
  • Eriksen, Bjorn Odvar, University Hospital of North Norway, Tromso, Norway
  • Palsson, Runolfur, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
  • Indridason, Olafur S., Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
Background

Kidney function is known to decline with age, nevertheless, a uniform definition of glomerular filtration rate (GFR) has been applied to define chronic kidney disease irrespective of age. This has mostly been based on cross-sectional studies using single assessment of estimated glomerular filtration rate (eGFR), that have indicated worse outcome at eGFR <60 mL/min/1.73 m2. The aim of this study was to examine the risk of all-cause mortality according to eGFR and proteinuria in persons aged >65 years in the general population.

Methods

We obtained all serum creatinine (SCr) and urine protein measurements from all clinical laboratories in Iceland in the years 2008-2016. Clinical data were obtained from nationwide electronic medical records. eGFR was calculated using the CKD-EPI equation and classified into categories; 0-29, 30-44, 45-59, 60-74, 75-89, 90-104 and >104 mL/min/1.73 m2 eGFR category and proteinuria had to be persistent for >3 months. A multiple imputation method was used to account for missing urine protein measurement data. A joint model using repeated measurements was used to assess mortality and simultaneously account for decline in eGFR over time, adjusting for age as a continuous variable, sex and multiple comorbid conditions.

Results

We obtained 782,995 SCr values for 37,937 individuals aged over 65 years, of whom 23,344 (62%) had information on proteinuria. The median age was 75 (range, 66-106) years and 46% were men. Adjusted hazard ratios for all-cause mortality are demonstrated in the table.

Conclusion

Among elderly individuals, eGFR >104 mL/min/1.73 m2 carries a high mortality risk, whereas eGFR of 45-74 without proteinuria is associated with the lowest mortality.

Adjusted hazard ratio (95% CI) for death according to eGFR and proteinuria
eGFR (mL/min/1.73 m2)No proteinuriaProteinuria
>1044.28 (2.88-6.36)4.47 (2.15-9.31)
90-1041.55 (1.40-1.73)2.23 (1.92-2.60)
75-891.08 (1.02-1.15)1.62 (1.50-1.75)
60-74Reference1.42 (1.32-1.54)
45-591.05 (0.99-1.12)1.46 (1.35-1.57)
30-441.33 (1.23-1.44)1.41 (1.28-1.55)
0-291.97 (1.75-2.21)2.09 (1.84-2.37)

Funding

  • Government Support – Non-U.S.