Effect of Clinical Variables and Immunosuppression on Serum Cystatin C and Beta-Trace Protein in Kidney Transplant Recipients

White, Christine A.; Akbari, Ayub; Doucette, Steve; Fergusson, Dean; Ramsay, Tim; Hussain, Naser; Dinh, Laurent; Filler, Guido; Lepage, Nathalie; Knoll, Greg A.

doi:10.1053/j.ajkd.2009.06.003

« Previous Next »American Journal of Kidney Diseases
Volume 54, Issue 5 , Pages 922-930, November 2009

Effect of Clinical Variables and Immunosuppression on Serum Cystatin C and Beta-Trace Protein in Kidney Transplant Recipients

Christine A. White, MD, MSc
- Department of Medicine, Division of Nephrology, Queen's University, Kingston, Canada
Ayub Akbari, MD
- Department of Medicine, Division of Nephrology, University of Ottawa, Ottawa, Canada
- Kidney Research Centre, Ottawa Health Research Institute, Ottawa, Canada
Steve Doucette, MSc
- Clinical Epidemiology Program, Ottawa Health Research Institute, Ottawa, Canada
Dean Fergusson, PhD
- Clinical Epidemiology Program, Ottawa Health Research Institute, Ottawa, Canada
Tim Ramsay, PhD
- Clinical Epidemiology Program, Ottawa Health Research Institute, Ottawa, Canada
Naser Hussain, MD
- Department of Medicine, Division of Nephrology, University of Ottawa, Ottawa, Canada
Laurent Dinh, MD
- Division of Nuclear Medicine, Department of Medicine, University of Ottawa, Ottawa, Canada
Guido Filler, MD
- Division of Nephrology, Department of Pediatrics, University of Western Ontario, London, Canada
Nathalie Lepage, PhD
- Department of Laboratory Medicine, Children's Hospital of Eastern Ontario and University of Ottawa, Ottawa, Canada
Greg A. Knoll, MD, MSc
- Department of Medicine, Division of Nephrology, University of Ottawa, Ottawa, Canada
- Kidney Research Centre, Ottawa Health Research Institute, Ottawa, Canada
- Clinical Epidemiology Program, Ottawa Health Research Institute, Ottawa, Canada
- Address correspondence to Greg A. Knoll, MD, MSc, Division of Nephrology, The Ottawa Hospital, Riverside Campus, 1967 Riverside Dr, Ottawa, Ontario, Canada K1H 7W9

Received 6 February 2009; accepted 5 June 2009. published online 21 July 2009.

Background

Cystatin C and beta-trace protein (BTP) are low-molecular-weight proteins that have generated interest as alternative endogenous markers of glomerular filtration rate (GFR). Studies examining the effect of demographic, biometric, clinical, and biochemical variables on cystatin C levels have yielded conflicting results, perhaps because of the reliance on inferior methods of GFR determination. The aim of this study is to examine the independent effect of various clinical parameters on serum concentrations of creatinine, cystatin C, and BTP in kidney transplant recipients.

Study Design

Cross-sectional study.

Setting & Participants

207 kidney transplant recipients with stable kidney function.

Predictors

GFR, age, race, sex, body mass index, albumin level, proteinuria, smoking status, prednisone, and calcineurin inhibitor and mycophenolate mofetil use.

Outcomes & Measurements

Multiple linear regression analysis was used to examine the relationship between predictor variables and cystatin C, BTP, and creatinine levels. GFR was measured by using technetium 99m–radiolabeled diethylenetriaminepentaacetic acid clearance.

Results

After adjusting for GFR, cystatin C and BTP levels were significantly lower in women compared with men. Greater albumin concentration was associated with significantly lower cystatin C and BTP concentrations. There was a statistically significant, but clinically small, association between body mass index and cystatin C level, but no association between the other demographic variables or medications analyzed.

Limitations

Predominantly white population; results may not be applicable to other racial groups.

Conclusion

Important nonrenal factors can influence BTP and cystatin C concentrations and need to be considered when interpreting BTP and cystatin C values in kidney transplant patients.

Index Words: Glomerular filtration rate, cystatin C, beta-trace protein, creatinine, kidney transplantation