Cross-sectional study on the association between C-reactive protein to albumin ratio (CAR) and sarcopenia risk in patients with type 2 diabetes mellitus

To investigate the association of C-reactive protein to albumin ratio (CAR) with sarcopenia and to evaluate its discriminative performance in patients with type 2 diabetes mellitus (T2DM). We enrolled 265 patients with T2DM within this single-center, retrospective study. Sarcopenia was diagnosed according to the 2019 Asian Working Group for Sarcopenia (AWGS) criteria. CAR was calculated as CRP (mg/L) divided by albumin (g/L) and categorized into tertiles. Multivariable logistic regression was used to assess the independent association between CAR and sarcopenia. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the discriminative performance. Sarcopenia was identified in 52 (19.6%) patients, who exhibited significantly higher CAR levels than those without sarcopenia (P < 0.05). CAR was negatively correlated with both appendicular skeletal muscle mass index (ASMI) and grip strength (P < 0.01). After adjusting for age, sex, BMI, diabetes duration, HbA1c, and eGFR, the highest CAR tertile was associated with a 3.12-fold increased risk of sarcopenia compared with the lowest tertile (OR = 3.12, 95% CI 1.08–9.02, P = 0.036). Furthermore, CAR demonstrated moderate predictive capacity for sarcopenia (AUC=0.768), which was superior to the neutrophil-to-lymphocyte ratio (AUC = 0.648). Elevated CAR is independently associated with increased odds of sarcopenia in T2DM. As a readily available and cost-effective composite marker of inflammation and nutrition, CAR may provide complementary information for sarcopenia risk stratification in T2DM.