Background: Chronic transplant dysfunction is characterized by a gradual decline in renal function with slowly rising serum creatinine. The underlying mechanism is thought to include inflammation and atherosclerosis. C-reactive protein (CRP) is a well-established marker of both inflammation and atherosclerosis. In this prospective study, we investigated whether CRP could be of use as a clinical marker for early identification of renal transplant recipients at increased risk of deterioration of graft function.
Methods: In this prospective study, all participating patients (n = 606) visited the out-patient clinic at least once a year, and serum creatinine was assessed at every visit. Subjects with a follow-up of <1 year (n = 31) were excluded from analysis.
Results: A total of 575 patients participated at a median (interquartile range) time of 5.9 (2.6-11.3) years post-transplantation. Median time of follow-up was 3.0 (2.4-3.4) years. Changes in serum creatinine during follow-up were -0.45 (-4.83-4.76) micromol/l/year in 172 subjects with CRP <1.0 mg/l, 1.04 (-3.36-6.12) micromol/l/year in 184 subjects with CRP 1.0-3.0 mg/l and 2.34 (-3.33-9.07) micromol/l/year in 219 subjects with CRP >3.0 mg/l (P < 0.05 for comparison of the three groups). Proteinuria (P = 0.003), CMV IgG titre (P = 0.01), donor age (P = 0.01), CRP concentration (P = 0.02), recipient age (P = 0.02) and recipient gender (P = 0.047) were independently associated with change in serum creatinine during follow-up in a multivariate analysis.
Conclusions: Elevated levels of CRP independently predict accelerated deterioration of graft function in renal transplant recipients >1 year post-transplantation. Further prospective studies are required to investigate whether early intervention can prevent deterioration of graft function in subjects with elevated levels of CRP.