Lower serum CTRP3 is related to more severe distal symmetric polyneuropathy in type 2 diabetic patients

Abstract 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 lower 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 DSPN group (n=89) and non-DSPN group (n=89). Both the anthropometric parameters and neurologic symptoms were recorded. Also, neurologic signs, neuropathy symptom score (NSS) and neuropathy disability score (NDS) were measured. Biochemical indexes, fasting insulin, and C peptide were detected. Serum CTRP3 concentrations were assayed by ELISA method. Results: Serum CTRP3 levels decreased significantly in DSPN group compared with 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 score of NSS or NDS, the lower the levels of serum CTRP3 (all P<0.05). Moreover, the patients with lower CTRP3 levels (<7.58ng/ml) had higher positive 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 displayed that the best cut-off value of CTRP3 for the prediction of DSPN was 7.55ng/ml (sensitivity 78.7%, specificity 79.8%), and the area under the curve (AUC) was 0.763 (95% CI 0.689-0.838, P<0.001). Conclusion: Lower serum CTRP3 is a strong predictor for the occurrence and progression of DSPN in Chinese patients with T2DM.