Proinsulin-to-C-Peptide Ratio as a Biomarker of Beta-Cell Stress and Glycemic Deterioration

Abstract

The proinsulin-to-C-peptide ratio reflects endoplasmic reticulum stress and inefficient insulin processing. In adults with new-onset type 2 diabetes, elevated baseline ratios predicted worsening glycemia and earlier need for treatment intensification independent of HbA1c. Adding the ratio to clinical models improved risk reclassification. Standardization of assays and thresholds is needed for broader clinical use.