Correlation between cortical renal thickness and estimated glomerular filtration rate in diabetic nephropathy patients

Background and Objectives: Conventionally urine creatinine test and renal ultrasound are used in clinical practice for staging and progression of diabetic nephropathy. The objectives of this study were (1) to determine the correlation between cortical renal thickness and eGFR (estimated glomerular filtration rate) in diabetic nephropathy, and (2) to further assess if the cortical renal thickness is a better predictor of eGFR than the linear bipolar length in diabetic nephropathy. Materials and Methods: A total of 163 patients were recruited between April 2017 and March 2018 (86 men and 77 women) who had diabetic nephropathy with eGFR <90mL/min/1.73 m2 according to Cockcroft–Gault formulation. Results: The mean age (mean ± standard deviation [SD]) of the patients was 59.5 ± 7.2 years with range 39 –78 years and the median age was 59 years. The mean level of creatinine (mean ± SD) of the patients was 1.4 ± 0.4 mg/dL with range 0.6–3.2 mg/dL and the median was 1.4 mg/dL. Mean eGFR (in mL/min/1.73 m2) being 49.8 ± 13.4 (range 41.2–62.5). Cortical renal thickness right upper part, right middle part, left upper part, and left middle part (in mm) were found to be 5.5 ± 1.04, 5.6 ± 1.05, 5.5 ± 1, and 5.6 ± 1.02, respectively. Mean values of renal length of right- and left-sided kidney were 9.2 ± 0.4 and 9.5 ± 0.4, respectively. Pearson’s coefficient of correlation showed a moderately significant correlation between eGFR and cortical renal thickness in diabetic nephropathy patients. Correlation coefficient of the cortical renal thicknesses correlated better with eGFR than cortical renal length. Summary and Conclusion: This cross-sectional study in diabetic nephropathy patients showed a positive correlation between eGFR and cortical renal thickness. Cortical renal thickness was found to be a better predictor of renal function than bipolar renal length.