Serum cystatin-C is not superior to serum creatinine in predicting glomerular filtration rate in cirrhotic patients

Assessment of glomerular filtration rate [GFR] by common creatinine-based methods is potentially inaccurate in patients with cirrhosis. Cirrhotic patients have several underlying conditions that contribute to falsely low serum creatinine concentrations, even in the presence of moderate to severe renal impairment. Therefore creatinine-based methods usually overestimate true GFR in these patients. Cystatin-C is a low molecular weight protein and an endogenous marker of GFR. We compared the accuracy of plasma cystatin-C and creatinine in assessing renal function in cirrhotic patients. We serially enrolled cirrhotic patients with stable renal function admitted in our ward if they met the inclusion criteria and consented to participate. Child-Pugh [CP] score was calculated for all patients. GFR was calculated using serum creatinine, serum cystatin-C, and 99m TC-DTPA clearance with the last one serving as the gold standard. The area under curve [AUC] on receiver-operating characteristic curves [ROC] were used to assess the diagnostic accuracy of each calculated GFR with that measured by DTPA. Fourty-eight patients were enrolled [32 males, 66.7%]. Nine were in class-A, 20 in class-B and 19 in class-C of CP. Cystatin-C did not perform well in predicting the true GFR, while serum creatinine performed relatively accurately at GFR<80ml/min [AUC=0.764, p=0.004]. Serum creatinine at a cutoff of 1.4 mg/ dl was 20% sensitive and 92% specific and with at a cutoff of 0.9 mg/dl was 77% sensitive and 72% specific for diagnosis of impaired renal function. Cystatin-C could not predict GFR effectively even after stratification for CP score, gender, and BMI. Serum creatinine could predict GFR<65ml/min in females [ROC curve AUC=0.844,p=0.045]. In those with BMI>20 kg/m2 a GFR<80 ml/min could also be predicted by serum creatinine [ROC curve AUC=0.739,p=0.034]. It also could predict GFR<80ml/min in patients with CP class A and B [ROC curve AUC=0.795,/7=0.01], but not in patients with CP class C. Neither serum creatinine nor Cystatin-C are good predictors of GFR in cirrhotic patients, although serum creatinine seems to perform better in selected subgroups

Tacrolimus rescue therapy for corticosteroid-resistant and polyclonal antibody-resistant kidney allograft rejections

The conventional treatment of acute kidney allograft injection consists of high-dose corticosteroids and polyclonal antibodies. We report our experience of tacrolimus rescue therapy in patients with acute rejections refractory to corticosteroids and polyclonal antibodies. A total of 34 patients with a mean age of 42.3 years and clinical diagnosis of acute kidney allograft rejection underwent tacrolimus rescue therapy when treatment with corticosteroids and polyclonal antibodies failed. Kidney allograft biopsy results were available in 21 patients. All of the patients received tacrolimus, 0.1 mg twice daily, and in those who responded to the therapy after 4 to 6 months, tacrolimus was replaced with cyclosporine. Pathologic examination of 21 biopsy specimens of the kidney allografts showed acute vascular rejection in 7 patients [33.3%, acute humoral rejection in 6 [28.6%], acute cellular rejection in 3 [14.3%], and accelerated acute rejection in 3 [14.3]. Twenty-six patients [76.5%] responded to rescue therapy with tacrolimus and discharged with a mean serum creatinine level of 1.4 mg/dL [range, 1.1 mg/dL to 1.7 mg/dL]. Allograft nephrectomy was done in 8 patients [23.5%] because of no response to treatment of rejection, the pathology reports of which consisted of acute vascular rejection in 5 patients and extensive necrosis in 3. Tacrolimus therapy is able to salvage kidney allograft with acute refractory injection. We recommend that tacrolimus be used as an alternative to the conventional drugs used for antirejection therapy. However, severe infectious complications as a result of overt immunosuppression must be considered