Long-term prospective observation suggests that glomerular hyperfiltration is associated with rapid decline in renal...

Glomerular hyperfiltration usually occurs early in development of kidney complications in diabetes. To understand hyperfiltration as a marker of renal disease progression in type 2 diabetes mellitus, we aimed to examine association between glomerular hyperfiltration (estimated glomerular filtration rate ⩾ 120 mL/min/1.73 m²) and rapid renal decline (annual estimated glomerular filtration rate loss ⩾ 3 mL/min/1.73 m²).

This was a prospective cohort comprising 1014 patients with type 2 diabetes mellitus attending a Diabetes Centre of a regional hospital in 2002-2014. A separate prospective cohort, comprising 491 patients who attended Diabetes Centre or primary-care polyclinics, was used for validation. We performed binary mediation analysis to examine role of hyperfiltration on relationship between baseline haemoglobin A1c and rapid renal decline.

Among patients in discovery cohort, 5.2% had baseline hyperfiltration. Over mean follow-up of 6 years, 22.9% had rapid glomerular filtration rate decline. Baseline hyperfiltration was significantly associated with greater odds of rapid renal decline after adjusting for demographics, diabetes duration and clinical covariates (odds ratio: 2.57; 95% confidence interval: 1.21-5.46; p = 0.014). Similar finding was found in validation cohort (odds ratio: 2.98; 95% confidence interval: 1.06-8.42; p = 0.034). Hyperfiltration significantly accounted for 35.3% of association between increasing baseline haemoglobin A1c and rapid renal decline.

Glomerular hyperfiltration is an independent risk factor of rapid renal decline. It mediates the association between increasing haemoglobin A1c and rapid renal decline.