Relationship between albuminuria and total proteinuria in systemic lupus erythematosus nephritis: diagnostic and therapeutic implications.
OBJECTIVE
Albuminuria is regarded a sensitive measure of progression of glomerular disease. This study was undertaken in patients who had systemic lupus erythematosus glomerulonephritis (n = 57) and were followed in the Ohio SLE Study to determine whether measuring albuminuria offered clinical advantages over that of total proteinuria.


METHODS
Twenty-four-hour urine collections (n = 127) were obtained at baseline and annually for measurement of microalbumin, total protein, and creatinine.


RESULTS
There was a strong linear relationship between microalbumin-creatinine and protein-creatinine ratios over the entire range of protein-creatinine ratios; however, in the protein-creatinine ratio range 0.0 to 0.3, as the protein-creatinine ratio increased, the microalbumin-protein ratio increased much more than the protein-creatinine ratio. Also, the greater the protein-creatinine ratio, the greater was the evidence for nonselective proteinuria (protein-creatinine ratio--microalbumin-creatinine ratio).


CONCLUSIONS
For the diagnosis of proteinuria renal flare, measuring albuminuria offers no advantage over measuring total proteinuria because changes in protein-creatinine and microalbumin-creatinine ratios are highly correlated over the designated ranges for systemic lupus erythematosus glomerulonephritis proteinuric flares. In those with normal-range proteinuria, subsequent changes in microalbumin-protein ratio might be a better forecaster of renal flare than changes in protein-creatinine or microalbumin-creatinine ratio. High protein-creatinine ratios are associated with evidence of nonselective proteinuria, which may increase the nephrotoxicity of proteinuria. Thus, using high-threshold criteria for systemic lupus erythematosus flare (allowing greater proteinuria increase before flare is declared) may expose the kidney to greater nephrotoxicity than using the low-threshold criteria for systemic lupus erythematosus flare.
Birmingham
Daniel J
DJ
Department of Internal Medicine, Ohio State University Medical Center, Columbus, OH 43210-1250, USA.
Rovin
Brad H
BH
Shidham
Ganesh
G
Bissell
Michael
M
Nagaraja
Haikady N
HN
Hebert
Lee A
LA
D000328:Adult; D000419:Albuminuria / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy / Q000652:urine; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008181:Lupus Nephritis / Q000150:complications / Q000628:therapy / Q000652:urine*; D008297:Male; D008875:Middle Aged; D009820:Ohio; D011237:Predictive Value of Tests; D011507:Proteinuria / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy / Q000652:urine
D003404:Creatinine