Kidney Week

Abstract: TH-PO1024

Small Kidney Size Relative to Body Mass Is a Risk Factor for Renal Function Deterioration in IgA Nephropathy Patients

Session Information

• Glomerular Diseases: Clinical, Outcomes, Trials - I
  October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

• Nam, Yooju, Yonsei University College of Medicine, SEOUL, Korea (the Republic of)

Yooju Nam,

• Lee, Seon yeong, Yonsei University College of Medicine, SEOUL, Korea (the Republic of)

Seon yeong Lee,

• Kim, Joohwan, Yonsei University College of Medicine, SEOUL, Korea (the Republic of)

Joohwan Kim,

• Nam, Ki Heon, Yonsei University College of Medicine, SEOUL, Korea (the Republic of)

Ki Heon Nam,

• Park, Jung Tak, Yonsei University Health System, Seodaemun-Gu, seoul, Korea (the Republic of)

Jung Tak Park,

• Han, Seung Hyeok, Yonsei University College of Medicine, SEOUL, Korea (the Republic of)

Seung Hyeok Han,

• Yoo, Tae-Hyun, Yonsei University College of Medicine, SEOUL, Korea (the Republic of)

Tae-Hyun Yoo,

Background

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. However, identifying IgAN patients at higher risks for renal function decline is still a challenge. Recent investigations have proposed kidney size to be a risk factor for renal function decline in kidney transplantation recipients. Therefore, this study aimed to investigate whether kidney size has an effect on renal function deterioration rate in patients with IgAN.

Methods

Retrospective analysis was preformed from electronic medical records of 516 biopsy-proven IgAN patients. Kidney length was considered as the longest longitudinal diameter from sonographic measurements obtained at the time of biopsy. The average length of both kidneys was divided by body mass index for each individual to make adjustments for subject size (BMI-adjusted kidney size). Renal outcome was defined as a composite of a ≥ 50% decline in estimated glomerular filtration rate (eGFR) from baseline or the onset of end-stage renal disease.

Results

The mean age of the patients was 40.4 ± 12.1 years and 211 patients (40.9%) were male. The mean eGFR was 79.6 ± 28.3 mL/min/1.73 m² and the average kidney length was 102.8 ± 8.8 mm at baseline. The median follow-up duration was 51 months. When the patients were grouped into tertiles based on BMI-adjusted kidney size, renal outcome occurred in 30 (17.0%), 25 (14.0%), and 12 (7.4%) patients in the 1st, 2nd, and 3rd tertile groups, respectively. The amount of proteinuria was lowest and eGFR was highest in the 3rd tertile of BMI-adjusted kidney size group. Multivariate Cox proportional analysis revealed that the risk of renal outcome significantly lower in the 3rd tertile group as compared to the 1st tertile group (hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.21-0.93; P = 0.031). Additionally, the risk of renal outcome significantly decreased as the BMI-adjusted kidney size increased (HR, 0.55; 95% CI, 0.36-0.86; P = 0.008). These results remained robust even after adjustments were made for confounding factors including baseline eGFR and proteinuria.

Conclusion

Small kidney size could be a risk factor for renal function decline in IgA nephropathy patients. Simple sonographic kidney size measurements may help stratifying progression risk in patients with IgA nephropathy.