TY - JOUR
T1 - Serial assessment of glomerular filtration rate in lupus nephropathy
AU - Petri, M.
AU - Bockenstedt, L.
AU - Colman, J.
AU - Whiting-O'Keefe, Q.
AU - Fitz, G.
AU - Sebastian, A.
AU - Hellmann, D.
N1 - Funding Information:
The General Clinical Research Center is supported by the Division of Research Resources (RR-79) of the National Institutes of Health. These studies were carried out in the General Clinical Research Center at Moffitt-Long Hospital, University of California, San Francisco, sup- ported by the Division of Research Resources (RR-79) of the National Institutes of Health. This study was supported in part by a grant from the Research Evaluation and Allocation Committee, University of California, San Francisco, and by the Northern California Chapter of the Arthritis Foundation. The authors thank Patricia Douglass for her contribution. This study was supported in part by a grant from the Northern California Chapter of the Arthritis Foundation. We thank Dr. David Price and Joyce Lehmann for help with technetium-DTPA renal clearances. We thank Drs. Wallace Epstein and Kenneth Fye for their support and Patricia Douglass for secretarial assistance.
PY - 1988
Y1 - 1988
N2 - In patients with lupus nephropathy (LN), previous studies have shown that creatinine clearance (C(Cr)) overestimates true glomerular filtration rate as measured by inulin clearance (C(In)), and that among patients the degree of overestimation is highly variable. We sought to determine whether the discrepancy between C(Cr)) and C(In) remains constant over time (months, years) in each individual patient, and therefore whether serial measurements of C(Cr) reliably reflect the direction and magnitude of change in C(In). Twenty-five patients with LN underwent simultaneous determinations of C(Cr) and C(In) performed two to four (mean 3.3) times over three years. In a given patient, it was found that the ratio of C(Cr)/C(In) changed substantially over time (mean SD 0.16 with 95% confidence interval of 0.12 to 0.20). Thus, in about 32% of cases the ratio of C(Cr)/CIn) will vary more than ± 16% from a previously measured value of C(Cr)/C(In). Patients with both high and low values of C(In) showed similar variability in C(Cr)/C(In) over time. Variability in C(Cr)/C(In) was found regardless of whether C(In) was increasing, decreasing, or constant over time. In nearly one-half of all measurements of C(Cr), the corresponding change in C(In) was directionally discordant. Iothalamate and technetium-DTPA renal clearances correlated highly with C(In) (R2 = 0.99). We conclude that the discrepancy between C(Cr) and C(In) can vary greatly over time in an individual patient. Consequently, serial C(Cr) does not accurately measure the direction or magnitude of change in glomerular filtration rate in lupus nephropathy.
AB - In patients with lupus nephropathy (LN), previous studies have shown that creatinine clearance (C(Cr)) overestimates true glomerular filtration rate as measured by inulin clearance (C(In)), and that among patients the degree of overestimation is highly variable. We sought to determine whether the discrepancy between C(Cr)) and C(In) remains constant over time (months, years) in each individual patient, and therefore whether serial measurements of C(Cr) reliably reflect the direction and magnitude of change in C(In). Twenty-five patients with LN underwent simultaneous determinations of C(Cr) and C(In) performed two to four (mean 3.3) times over three years. In a given patient, it was found that the ratio of C(Cr)/C(In) changed substantially over time (mean SD 0.16 with 95% confidence interval of 0.12 to 0.20). Thus, in about 32% of cases the ratio of C(Cr)/CIn) will vary more than ± 16% from a previously measured value of C(Cr)/C(In). Patients with both high and low values of C(In) showed similar variability in C(Cr)/C(In) over time. Variability in C(Cr)/C(In) was found regardless of whether C(In) was increasing, decreasing, or constant over time. In nearly one-half of all measurements of C(Cr), the corresponding change in C(In) was directionally discordant. Iothalamate and technetium-DTPA renal clearances correlated highly with C(In) (R2 = 0.99). We conclude that the discrepancy between C(Cr) and C(In) can vary greatly over time in an individual patient. Consequently, serial C(Cr) does not accurately measure the direction or magnitude of change in glomerular filtration rate in lupus nephropathy.
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U2 - 10.1038/ki.1988.257
DO - 10.1038/ki.1988.257
M3 - Article
C2 - 3210545
AN - SCOPUS:0024207889
SN - 0085-2538
VL - 34
SP - 832
EP - 839
JO - Kidney international
JF - Kidney international
IS - 6
ER -