Patients With Mild ADPKD by Kidney Imaging but Low Estimated GFR

Abstract

Introduction

High height-adjusted total kidney volume (HtTKV) and low estimated glomerular filtration rate (eGFR) typically indicate high cystic burden by imaging and low kidney function, respectively, identifying high-risk patients for disease progression in autosomal dominant polycystic kidney disease (ADPKD). Here, we report the prevalence, clinical characteristics, and causes of mild ADPKD in patients using imaging and low eGFR, an ill-defined clinical scenario.

Methods

We studied 473 patients with kidney function measurements, PKD1 and PKD2 genetic screen, and total kidney volume (TKV) measurements by magnetic resonance imaging (MRI) or computed tomography. Mayo Clinic Imaging Classification (MCIC) based on age and HtTKV was used to assess cystic disease severity. Patients with a discordant phenotype were defined as those with MCIC 1A/B and eGFR < 80 ml/min per 1.73 m². We reviewed medical records to compare patients with and without the discordant phenotype, examining clinical characteristics such as second kidney disease(s), nephrotoxic exposure, diabetes mellitus, and metabolic syndrome-related traits.

Results

Of 473 patients, 55 (12%) displayed a discordant phenotype. Among these patients, 13 (24%) had normal kidney functions by 24-h creatinine clearance (CrCl₂₄) (> 80 ml/min per 1.73 m²) and high urinary creatinine excretion rates, indicating underestimation of their kidney function by eGFR likely because of high muscle mass. In addition, discordant patients showed a higher prevalence of hypertension (82% vs. 57%, P < 0.001), dyslipidemia (58% vs. 15%, P < 0.001), diabetes mellitus (15% vs. 3%, P < 0.05), and a second kidney disease (16% vs. 1%, P < 0.001).

Conclusion

Mild ADPKD by imaging with low eGFR represents a significant clinical scenario with conflicting prognostic indicators, underscoring the need for delineating underlying causes and providing more appropriate management.