Glomerular Hyperfiltration Predicts Kidney Function Decline and Mortality in Type 1 and Type 2 Diabetes: A 21-Year Longitudinal Study

OBJECTIVE: To evaluate the prognostic value of glomerular hyperfiltration on long-term kidney-related outcomes and mortality in patients with diabetes. RESEARCH DESIGN AND METHODS: We retrospectively analyzed 21-year longitudinal data from 314 patients with long-standing type 1 or type 2 diabetes. Glomerular hyperfiltration was identified based on the age- and sex-specific distribution of measured glomerular filtration rate (mGFR) by (99m)Tc-DTPA dynamic renal scintigraphy. The primary outcome was a composite of doubling of serum creatinine, end-stage kidney disease (ESKD), or cardiorenal death. The kidney-specific outcome was a composite of doubling of serum creatinine, ESKD, or renal death. RESULTS: Over a median of 21.0 years, the primary composite outcome occurred in 25 (39.7%), 24 (38.1%), and 46 (24.5%) participants with high mGFR (H-mGFR) (n = 63), low mGFR (L-mGFR) (n = 63), or normal mGFR (N-mGFR) (n = 188), respectively. Compared with N-mGFR, the hazard ratio (HR) for the primary composite outcome was 2.09 (95% CI 1.25–3.49) in H-mGFR and 1.81 (1.05–3.16) in L-mGFR. The HR for the kidney-specific composite outcome was 4.95 (2.21–11.09) in H-mGFR and 3.81 (1.70–8.56) in L-mGFR. The HRs for doubling of serum creatinine and cardiorenal death were 4.86 (2.18–10.90) and 2.18 (1.24–3.83) in H-mGFR and 4.04 (1.77–9.20) and 2.26 (1.27–4.01) in L-mGFR, respectively. CONCLUSIONS: Glomerular hyperfiltration, similar to hypofiltration, increases the combined risk of worsening kidney function and mortality from cardiovascular or renal causes in patients with diabetes. These findings encourage the active screening of these patients to optimize risk stratification and treatment of subclinical kidney disease.