A discrepancy between cystatin C– and creatinine-based kidney function estimates may help identify higher cardiovascular risk in individuals with type 1 diabetes mellitus (T1DM). Shrunken pore syndrome (SPS), defined by a greater difference between cystatin C-and creatinine-based estimated glomerular filtration rate (eGFR), was evaluated in an observational study published in Diabetes Care.

The analysis included 3,769 participants from the Finnish Diabetic Nephropathy Study (FinnDiane) with available serum creatinine and cystatin C data.

SPS (eGFRcys/eGFRcr cutoff 0.7) was not associated with coronary artery disease (CAD) or stroke. Among individuals without albuminuria, SPS was associated with HF (HR 3.07; 95% CI 1.47-6.38), PAD (HR 3.64; 95% CI 1.75-7.57), and all-cause mortality (HR 3.08; 95% CI 1.86-5.11). In those with albuminuria, SPS was associated only with HF (HR 1.54; 95% CI 1.02-2.33).

Among participants without albuminuria, similar associations were observed when the eGFRcys/eGFRcr ratio was analyzed as a continuous variable and with eGFRcys alone. In those with albuminuria, both eGFRcys and eGFRcr were independently associated with all studied outcomes.

The findings suggest that comparing cystatin C– and creatinine-based eGFR may help identify elevated risk for HF, PAD, and mortality in T1D before albuminuria develops.