Chromium-51 ethylenediamine tetraacetic acid glomerular filtration rate: a better predictor than glomerular filtration rate calculated by the Cockcroft-Gault formula for renal involvement in systemic lupus erythematosus patients

Establishment of normal reference ranges for total and separate glomerular filtration rates in living kidney donors by Gates' method after renal depth measured using single-photon emission computed tomography/computed tomography

BACKGROUND

The underestimation of renal depth by Tønnesen formula in Gates' method, which has been confirmed by many scholars, leads to the underestimation of both separate glomerular filtration rate (gSGFR) and total glomerular filtration rate (gTGFR). This study aimed to establish the normal reference ranges of renal depth-calibrated gTGFR and gSGFR in Chinese healthy adults, and to analyze the influencing factors.

METHODS

Renal depth was measured by CT scan followed by technetium 99m-diethylene triamine pentaacetic acid (99mTc-DTPA) renal dynamic imaging by single-photon emission computed tomography/computed tomography (SPECT/CT) in 329 living kidney donors. The renal depth-calibrated gTGFR and gSGFR were calculated by Gates' method with renal depth measured by CT instead of being calculated by the Tønnesen formula. A general linear model based on age, gender, body height, body weight, and BMI was used to analyze factors influencing gSGFR (L), gSGFR (R) and gTGFR.

RESULTS

The average gSGFR (L), gSGFR (R), and gTGFR for patients aged 23-64 years old were 49.3±10.1, 49.9±10.4, and 99.1±18.7 mL/min/1.73 m2, respectively. The gSGFR (L), gSGFR (R) and gTGFR for patients aged 41-50 years old were 26.9-69.3, 27.7-68.8, and 57.5-135.3 mL/min/1.73 m2, respectively, and those for patients aged 51-60 years old were 31.0-61.5, 29.5-63.3, and 64.6-120.7 mL/min/1.73 m2, respectively. gSGFR (L), gSGFR (R) and gTGFR had statistical significance with body height and age (P<0.05); however, there was no significant difference with gender, body weight, and BMI (P>0.05). For each 1 year increase in age, the gSGFR (L), gSGFR (R), and gTGFR decreased by 0.17, 0.28, and 0.44 mL/min/1.73 m2, respectively, while for every 1 cm increase in body height, the gSGFR (L), gSGFR (R), and gTGFR decreased by 0.37, 0.36, and 0.74 mL/min/1.73 m2, respectively.

CONCLUSIONS

Normal reference ranges for renal depth-calibrated gSGFR (L), gSGFR (R), and gTGFR were established in healthy Chinese adults aged 23-64 years, and gSGFR (L), gSGFR (R), and gTGFR decreased with age and body height.

Estimation of glomerular filtration rate in patients with systemic lupus erythematosus

The objective of this study was to compare the limit of agreement of creatinine clearance (CrCl) estimated by different equations with the CrCl measured by 24-hour urine collection in Hong Kong Chinese patients with systemic lupus erythematosus (SLE). Forty-three SLE patients with mild to moderate renal impairment (serum creatinine concentration 80 mol/L to 300 mol/L for females; and 106 mol/L to 300 mol/L for males) and not requiring renal replacement therapy were assessed. The estimated clearances were calculated by the Cockcroft-Gault (CG) equation, the Modification of Diet in Renal Disease (MDRD) study equation and the abbreviated MDRD (aMDRD) study equation. The estimated clearances were compared against the measured CrCl by 24- hour urine collection for their limit of agreement. Forty-three patients with mean (SD) age of 41.6 (8.4) years were assessed. As compared to the measured CrCl in patients with SLE, the clearances by CG equation, MDRD and aMDRD equations predicted a mean difference of 0.8% (95% confidence interval, 43.9-42.3%); 8.6% (95% CI, 24.3-7.2%) and 4.7% (95% CI, 21.4-12%), respectively. There is a tendency for the MDRD and aMDRD study equations to underestimate CrCl. The MDRD and aMDRD study equations have better predictive value than the CG equation.

Beyond immunosuppression – challenges in the clinical management of lupus nephritis

Lupus nephritis remains the most common severe manifestation of SLE with increased risk of death and end-stage renal disease. Although, recent research has focused on the choice of immunosuppressive in its treatment, other factors, including the quality and delivery of healthcare, the management of glucocorticoids and co-morbidity are probably of more importance. There has been significant progress in induction regimes with the successful use of mycophenolate mofetil, low dose intravenous cyclophosphamide and development of sequential regimens whereby cyclophosphamide is followed by an alternative immunosuppressive. However, the attention on the day-to-day management of lupus nephritis in the clinic has merited less attention. In this article, we aim to address more widely the major issues which are encountered regularly in the long-term management of these patients. The overall goals are the reduction of mortality and preservation of renal function.