Low serum CTRP3 is related to more severe distal symmetric polyneuropathy in type 2 diabetes patients.

Background: Distal symmetric polyneuropathy (DSPN) is one of the most common chronic complications in patients with type 2 diabetes mellitus (T2DM). Our previous study found that serum C1q tumor necrosis factor-related protein 3 (CTRP3) levels were decreased in type 2 diabetic patients. Thus, this study was designed to reveal the relationship between low serum CTRP3 and the prevalence and severity of DSPN.

Methods: A total of 178 cases of patients with T2DM were enrolled in the study. The subjects were divided into the DSPN group (n = 89) and the non-DSPN group (n = 89). Both anthropometric parameters and neurologic symptoms were recorded. Furthermore, neurologic signs, the neuropathy symptom score (NSS), and the neuropathy disability score (NDS) were assessed. Biochemical indexes, fasting insulin, and C peptide were measured. Serum CTRP3 concentrations were assayed using the ELISA method.

Results: Serum CTRP3 levels decreased significantly in the DSPN group compared with the non-DSPN group (P < 0.05). CTRP3 was negatively associated with the number of positive signs, NSS score, and NDS score in patients with DSPN (all P < 0.05). Interestingly, the higher the NSS score or NDS score, the lower were the levels of serum CTRP3 (all P < 0.05). Moreover, patients with lower CTRP3 levels (< 7.58ng/ml) had a higher rate of neurologic signs (all P < 0.05). Binary logistic regression analysis showed that CTRP3 independently predicted the occurrence of DSPN (β = -0.316, P < 0.001). ROC curve analysis revealed that the best cut-off value of CTRP3 for the prediction of DSPN was 7.55ng/ml (sensitivity 78.7%, specificity 79.8%), the area under the curve (AUC) was 0.763 (95% CI 0.689-0.838, P < 0.001).

Conclusion: Low serum CTRP3 could be a predictor for the occurrence and progression of DSPN in Chinese patients with T2DM.