Serum C-reactive protein to albumin ratio as a reliable marker of diabetic neuropathy in type 2 diabetes mellitus

In various diseases characterized by inflammation, the C-reactive protein to albumin ratio (CAR) serves as a marker of inflammation. Type 2 diabetes mellitus (T2DM) is frequently complicated by diabetic neuropathy (DN) and timely diagnosis is crucial for treatment and potential reversal of this complication. Since both DN and T2DM are associated with chronic, low-grade inflammation, our study aimed to evaluate CAR levels in type 2 diabetic subjects with DN and compare them to those in subjects without DN. Patients presenting to our institutional outpatient clinics were divided into two groups based on the presence of DN. Data on characteristics and laboratory measures, including CAR, were compared between the DN and non-DN groups. The median CAR in the DN and non-DN group was 2.19% (range 0.2 – 49%) and 0.56% (range 0.02 – 5.8%), respectively (P < 0.001). CAR showed significant positive correlations with weight (r = 0.19, P = 0.01), body mass index (BMI) (r = 0.11, P = 0.03), waist circumference (r = 0.10, P = 0.046), fasting glucose (r = 0.14, P = 0.004), serum creatinine (r = 0.25, P < 0.001), triglyceride (r = 0.17, P < 0.001), and low density lipoprotein (LDL)-cholesterol (r = 0.13, P = 0.001) levels, and an inverse correlation with estimated glomerular filtration rate (eGFR) (r = -0.16, P <0.001). Additionally, CAR demonstrated a sensitivity of 78% and specificity of 73% for predicting DN at a threshold of 1.02% (area under curve [AUC] 0.84, 95% confidence interval [CI] 0.82 – 0.87, P < 0.001). High CAR levels were independently associated with an increased risk of DN (odds ratio [OR] 1.34, 95% CI 1.08 – 1.62, P < 0.001). Elevated CAR levels may thus be considered a potential marker for DN in T2DM patients.