High prevalence of stage 3 chronic kidney disease in older adults despite normal serum creatinine.

BACKGROUND

Serum creatinine is commonly used to diagnose chronic kidney disease (CKD), but may underestimate CKD in older adults when compared with using glomerular filtration rates (eGFR). The magnitude of this underestimation is not clearly defined.

OBJECTIVE

Using the Modification of Diet in Renal Disease (MDRD) equation, to describe both the prevalence and the magnitude of underestimation of stage 3 CKD (GFR 30-59 ml/min/1.73 m(2)), as well as ideal serum creatinine cutoff values to diagnose stage 3 CKD among Americans > or =65 years of age.

DESIGN

Cross-sectional.

PARTICIPANTS

A total of 3,406 participants > or =65 years of age from the 1999-2004 National Health and Nutrition Examination Surveys (NHANES).

MEASUREMENTS: Serum creatinine levels were used to determine eGFR from the MDRD equation. Information on clinical conditions was self-reported.

RESULTS

Overall, 36.1% of older adults in the US have stage 3 or greater CKD as defined by eGFR values. Among older adults with stage 3 CKD, 80.6% had creatinine values < or =1.5 mg/dl, and 38.6% had creatinine values < or =1.2 mg/dl. Optimal cutoff values for serum creatinine in the diagnosis of stage 3 CKD in older adults were > or =1.3 mg/dl for men and > or =1.0 mg/dl for women, regardless of the presence or absence of hypertension, diabetes, or congestive heart failure.

CONCLUSION

Use of serum creatinine underestimates the presence of advanced (stage 3 or greater) CKD among older adults in the US. Automated eGFR reporting may improve the accuracy of risk stratification for older adults with CKD.