Age- and height-adjusted total kidney volume growth rate in autosomal dominant polycystic kidney diseases

Area of Science:

• Nephrology
• Medical Imaging
• Genetics

Background:

• Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by kidney cyst formation.
• The Mayo Clinic Image Classification (MIC) model predicts renal prognosis in ADPKD using height-adjusted total kidney volume (HtTKV) growth.
• Current MIC models assume exponential HtTKV increase, calculated via HtTKV slope from multiple measurements.

Purpose of the Study:

• To evaluate the efficacy of a novel age-adjusted HtTKV growth rate (AHTKV-α) as a predictor of renal prognosis in ADPKD.
• To compare the repeatability and predictive accuracy of AHTKV-α against the traditional HtTKV slope.
• To investigate the correlation between AHTKV-α and HtTKV slope with disease manifestations, eGFR decline, renal survival, and PKD genotype.

Main Methods:

• AHTKV-α was calculated using a single HtTKV measurement and patient age.
• Repeatability and correlation analyses were performed in 296 ADPKD patients, comparing AHTKV-α and HtTKV slope.
• PKD genotype influences were assessed in 88 patients with characterized mutations.

Main Results:

• AHTKV-α demonstrated significantly smaller absolute differences between baseline and follow-up measures compared to HtTKV slope.
• ADPKD subgroups stratified by baseline AHTKV-α showed earlier disease onset and steeper eGFR decline.
• AHTKV-α, unlike HtTKV slope, was significantly higher in PKD1 mutation carriers than PKD2 carriers, indicating greater predictive value.

Conclusions:

• The MIC model, utilizing AHTKV-α, is a reliable renal prediction tool applicable to Japanese ADPKD patients.
• AHTKV-α is a more sensitive and reliable indicator of TKV growth rate for ADPKD prognosis than the HtTKV slope.
• AHTKV-α offers improved stratification of disease severity and progression compared to the HtTKV slope.