To investigate the association between "shrunken pore syndrome" (SPS), defined as a large discrepancy between estimated glomerular filtration rates based on cystatin C (eGFRcys) and creatinine (eGFRcr), and coronary artery disease (CAD), stroke, peripheral artery disease (PAD), heart failure (HF), and all-cause mortality in individuals with T1D with and without albuminuria. The study comprised 3,769 individuals with and without albuminuria from the Finnish Diabetic Nephropathy Study (FinnDiane) who had both serum creatinine (Scr) and serum cystatin C (SCysC) data available. SPS (eGFRcys/eGFRcr ratio cutoff = 0.7) was not associated with CAD or stroke. In those with SPS but without albuminuria, the hazard ratios (HRs) for HF, PAD, and all-cause mortality were 3.07 (95% CI 1.47-6.38), 3.64 (95% CI 1.75-7.57), and 3.08 (95% CI 1.86-5.11). The associations between the eGFRcys/eGFRcr ratio as a continuous variable, as well as eGFRcys alone and HF, PAD, and all-cause mortality were significant in those without albuminuria. In individuals with albuminuria, SPS was only associated with HF (HR = 1.54; 95% CI 1.02-2.33), whereas the eGFRcys/eGFRcr ratio as a continuous variable was not associated with any of the outcomes. On the contrary, both eGFRcys and eGFRcr were independently associated with all studied outcomes in those with albuminuria. Findings highlight the clinical potential of identifying individuals at increased risk of HF, PAD, and all-cause mortality at an early stage among those with T1D without albuminuria by evaluating both eGFRcys and eGFRcr and their discrepancy.