Glomerular hyperfiltration in type I, type II, and secondary diabetes

Area of Science:

• Nephrology
• Endocrinology
• Diabetology

Background:

• Glomerular hyperfiltration is a known risk factor for diabetic nephropathy.
• Its prevalence in diabetes types beyond type I (insulin-dependent) is not well-established.

Purpose of the Study:

• To determine the occurrence of glomerular hyperfiltration in various diabetes mellitus types.
• To investigate associations between hyperfiltration and metabolic factors, and urinary albumin excretion.

Main Methods:

• Measured glomerular filtration rate (GFR) in 158 diabetic patients (type I, type II with/without insulin, secondary diabetes).
• Classified filtration status (hyper-, normo-, hypo-) against 36 age-matched controls.
• Analyzed associations with blood glucose, apolipoprotein B/A1 ratio, and urinary albumin excretion, excluding patients with renal disease or hypertension.

Main Results:

• Glomerular hyperfiltration was detected in 35% of type I and 32% of type II (non-insulin) diabetics.
• One case each in secondary diabetes and type II (insulin) diabetics showed hyperfiltration.
• Hyperfiltration correlated with high blood glucose in type I and high apolipoprotein B/A1 ratio in type II (non-insulin) diabetics.
• A positive correlation was found between GFR and urinary albumin excretion in hyperfiltering subjects (r = 0.33, p = 0.05).

Conclusions:

• Glomerular hyperfiltration is present across all types of diabetes mellitus.
• Hyperfiltration is associated with specific metabolic markers depending on diabetes type.
• Increased GFR and albuminuria in hyperfiltering individuals suggest early renal involvement.