Development of glomerular hyperfiltration, a multiphasic phenomenon.

Area of Science:

• Nephrology
• Renal Physiology
• Epidemiology

Background:

• The long-term GFR trajectory in relation to glomerular hyperfiltration (GHF) is not well understood.
• Investigating GHF requires understanding its temporal profile and predictive factors.

Purpose of the Study:

• To elucidate the temporal profile of estimated GFR (eGFR) in individuals who develop GHF.
• To identify predictors of incident GHF.

Main Methods:

• Retrospective analysis of 23,982 GHF-free health examinees followed for 2-10 years.
• GFR estimated using serum creatinine; GHF defined as age- and sex-specific eGFR ≥ 95% of the Japanese general population.
• Temporal eGFR profiles analyzed using a random coefficient linear mixed model.

Main Results:

• Of 23,982 subjects, 797 developed GHF (GHF_(+) group) and 23,185 did not (GHF_(-) group).
• GHF_(+) group had higher baseline eGFR (94.1 vs 77.3 mL/min/1.73 m²).
• GHF_(+) group showed sustained eGFR elevation for ~3.3 years, followed by a surge to 108.5 mL/min/1.73 m², and a steeper eGFR decline (-0.984 mL/min/1.73 m²/yr) compared to the GHF_(-) group (-0.497 mL/min/1.73 m²/yr).
• Baseline eGFR strongly predicted incident GHF (AUC 0.87).

Conclusions:

• Glomerular hyperfiltration is a chronic, multiphasic phenomenon.
• It involves initial sustained GFR elevation, a subsequent surge, and accelerated GFR decline.
• Baseline eGFR is a key predictor of developing GHF.