Serum creatinine levels correlate with plasma amyloid Beta protein.

The authors investigated the effect of renal function on plasma amyloid beta protein (Abeta) by analyzing the relationship between creatinine (Cr) and Abeta40 or Abeta42 in plasma from 59 normal control subjects (NC) and 220 Alzheimer disease (AD) patients. In all 279 subjects, Cr was significantly associated with Abeta40 (p < 0.001) and Abeta42 (p < 0.01), accounting for 7.3% and 3.1% of shared variance, respectively. Significant associations were also present in NC and AD groups separately. These results indicate that it may be useful to consider Cr levels when measuring plasma Abeta.