Serum cystatin C reflects the progress of albuminuria

Abstract

Background: Research on the relationship between urinary albumin excretion and serum cystatin C in diabetes is restricted to cross-sectional studies. In this study, we investigated how well serial measurements of serum cystatin C level reflect changes in the urinary albumin excretion rate.

Methods: We enrolled and retrospectively collected data on 1,058 participants with type 2 diabetes who were older than 18 years and who had more than 3 years of follow-up with serial measurements of albuminuria and serum cystatin C at an outpatient clinic.

Results: With the use of a linear mixed model, we found that the albuminuria level for each patient over time corresponded with the annual change in serum cystatin C-based estimated glomerular filtration rate (cysC-eGFR) but did not correspond with the creatinine-based eGFR calculated by the modification of diet in renal disease formula (MDRD-eGFR). The discrepancy in the direction of the trend was smaller with cysC-eGFR than with MDRD-eGFR.

Conclusion: Serum cystatin C level reflects the trend in albuminuria level more accurately than serum creatinine level in Korean type 2 diabetes mellitus patients.

Keywords: Albuminuria; Creatinine; Cystatin C; Diabetes mellitus, type 2; Diabetic nephropathies.

Fig. 1

Selection of study participants.

Fig. 2

Accordance of change rate between urinary albumin/creatinine ratio and estimated glumerular filtration rate (eGFR) calculated by (A) modification of diet in renal disease (MDRD) formula or (B) serum cystatin C. Trend accordance (percent of subjects in white box) is 23.8% in (A) and 39.4% in (B).

Fig. 3

Accordance of change between urinary albumin/creatinine ratio and estimated glumerular filtration rate (eGFR) calculated by (A) modification of diet in renal disease (MDRD) formula or (B) serum cystatin C. Trend accordance (percent of subjects in white box) is 36.8% in (A) and 52.3% in (B).