The association of plasma fluorescent oxidation products and chronic kidney disease: a case-control study.

BACKGROUND/AIMS: Plasma fluorescent oxidation products (FLOP) constitute a stable and easily measured biomarker of cumulative oxidative stress. However, their association with chronic kidney disease (CKD) has not been studied.

METHODS

We examined the association of FLOP and CKD in 201 CKD patients and 201 controls without CKD from the community. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) or the presence of albuminuria.

RESULTS

Adjusted median (interquartile range) FLOP levels were significantly higher in patients with CKD than in controls [FLOP1 (lipid oxidation products): 215.2 (181.3-268.7) vs. 156.6 (139.6-177.3) fluorescent intensity units/ml, p < 0.0001; FLOP2 (DNA oxidation products): 534.8 (379.3-842.4) vs. 269.9 (232.4-410.5) fluorescent intensity units/ml, p < 0.0001; FLOP3 (protein and phospholipid oxidation products): 51.4 (44.4-66.0) vs. 45.2 (38.3-51.7) fluorescent intensity units/ml, p = 0.002]. Compared with those with a FLOP level below the 75th percentile, participants with a FLOP level above the 75th percentile had increased odds of CKD after adjustment for covariables (FLOP1: odds ratio 13.1, 95% confidence interval 6.2-27.6; FLOP2: odds ratio 5.7, 95% confidence interval 2.9-11.1; FLOP3: odds ratio 2.4, 95% confidence interval 1.2-4.7). Levels of FLOP1, FLOP2 and FLOP3 were related to eGFR (p < 0.0001 for all) and log-transformed urine albumin (p < 0.005 for all) in multivariable-adjusted linear regression models.

CONCLUSION

These data indicate that an elevated FLOP level is associated with CKD status and severity. Future studies are warranted to elucidate its role in the development and progression of CKD.