Abstract: SA-PO406

Prevalence of CKD in the Healthy Elderly Using the Aspirin in Reducing Events in the Elderly (ASPREE) Study Cohort

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 302 CKD: Estimating Equations, Incidence, Prevalence, Special Populations

Authors

  • Polkinghorne, Kevan, Monash Medical Centre and Monash University, Melbourne, Victoria, Australia
  • Wolfe, Rory, Monash University, Melbourne, Victoria, Australia
  • Woods, Robyn L, Monash University, Melbourne, Victoria, Australia
  • Mcneil, John James, Monash University, Melbourne, Victoria, Australia
  • Nelson, Mark, University Of Tasmania, Hobart, New South Wales, Australia
  • Reid, Christopher M, Monash University, Melbourne, Victoria, Australia
  • Murray, Anne M., Hennepin County Medical Center, Minneapolis, Minnesota, United States

Group or Team Name

  • ASPREE investigators
Background

The diagnosis & definition of CKD in the elderly is controversial. GFR declines with age such that reduced eGFR is common in the elderly but may not reflect true underlying kidney related disease. The ASPREE study is an international (Australia, US) RCT designed to assess whether daily treatment with aspirin extends the duration of life free of dementia & physical disability in healthy elderly participants who are free of diagnosed cardiovascular disease or disability. Subjects with diabetes &/or hypertension (unless poorly controlled) were included. We assessed prevalence & predictors of CKD in this cohort using the MDRD and CKD-Epi eGFR equations as well as the elderly specific Berlin Initiative Study equation 1 (BIS1).

Methods

A cross sectional analysis of the ASPREE cohort at randomisation was performed. eGFR was estimated using all 3 equations. CKD was defined as eGFR<60 ml/min with or without albuminuria. CKD prevalence was calculated using each equation and compared. Predictors of CKD were assessed by logistic regression.

Results

17,931 subjects (15,588 Australia, 2,343 USA) had complete data from urine and blood testing. Mean age was 75 years (SD 4.6), 56% were female, 76% had hypertension and 9% diabetes mellitus. Median UACR was 0.8 (IQR 0.5, 1.6) mg/mmol. Mean eGFR by CKD-Epi was 72.8 (SD 14.3) ml/min. CKD prevalence was similar by the MDRD and CKD-Epi equations (19 and 18% respectively) but substantially higher by the BIS1 equation (41%). This difference was predominantly driven by reclassification of individuals from stage 2 CKD to stage 3a without albuminuria. 69% of those with CKD by CKD-Epi had stage 3a without albuminuria compared to 75% of those using the BIS1 equation. An increased risk of CKD was related to participants being older, female, diabetic, or having higher BMI.

Conclusion

The prevalence of CKD in this healthy elderly population was 19% (CKD-Epi) and lower than previously described in the US (47% by CKD-Epi). The elderly-specific GFR equation BIS1 doubled the prevalence of CKD with the majority reclassified from stage 2 to stage 3a CKD.

Funding

  • Other NIH Support