Effects of Serum C-Peptide Level on Blood Lipid and Cardiovascular and Cerebrovascular Injury in Patients with Type 2 Diabetes Mellitus: A Meta-Analysis

Relationship Between Fasting C-Peptide to Diabetes Duration Ratio (FCP/DD) and Diabetic Peripheral Neuropathy

PURPOSE

To explore the correlation between fasting C-peptide to diabetes duration ratio (FCP/DD) and diabetic peripheral neuropathy (DPN).

METHODS

The study was conducted on 816 patients with type 2 diabetes (T2DM). Subjects were classified into a diabetic peripheral neuropathy group (DPN, n=408) and a non-diabetic peripheral neuropathy group (NDPN, n=408) depending on the presence of DPN. Collected patients' baseline data, calculated the FCP/DD ratio, and analyzed the correlation between FCP/DD and DPN.

RESULTS

A comparative analysis of general characteristics revealed that the DPN group exhibited higher values for age, DD, proportion of hypertension, proportion of DN, and proportion of DR compared to the NDPN group, Conversely, the DPN group demonstrated lower proportions of eGFR, FCP/DD, FCP, and fatty liver relative to the NDPN group, with all differences achieving statistical significance (P < 0.05). Compared to the high FCP/DD group, the low FCP/DD group exhibited higher values in age, DD, the proportion of DPN, DN, DR, and hypertension, as well as elevated levels of HDL-C and NEUT (P<0.05). Conversely, the low FCP/DD group demonstrated a lower proportion of patients who smoked and those with fatty liver, along with reduced BMI, ALB, FBG, UA, eGFR, TC, TG, and LDL-C levels (P < 0.05). In patients with T2DM, after adjusting for confounding factors, high levels of FCP/DD were found to be a protective factor for DPN (P < 0.05). The area under the curve of the FCP/DD Model predicting DPN (AUC=0.737) was higher than that of single FCP (AUC=0.587), DD (AUC=0.665).

CONCLUSION

The high FCP/DD ratio was a protective factor for T2DM with DPN. Additionally, the FCP/DD ratio was found to be a better predictor for the occurrence of DPN in T2DM compared to FCP and DD alone.

The association of serum C-peptide with the risk of cardiovascular events: a meta-analysis and systematic review

BACKGROUND

C-peptide is considered a peptide with active function in the body, which can affect people's health. However, the results of previous studies on the possible association of C-peptide with the risk of cardiometabolic disorders have not been fully understood. This systematic review and meta-analysis aimed to investigate the association between serum C-peptide level and the risk of cardiovascular disease (CVD) events.

METHODS

The various important databases, including PubMed, Scopus, and Web of Science, were searched comprehensively to November 2022 to identify the relevant studies. The HR(95% CI) or OR(95% CI) for observational studies were extracted and converted into log HR or log OR and their standard deviation(SD) was computed. A random-effects model with an inverse variance weighting method was conducted, to calculate the pooled effect size.

RESULTS

Sixteen observational studies, including one case-control study, eight cohort studies, and seven cross-sectional studies were included in the current meta-analysis. The sample size ranged from 90 to 7030, with an age range from 12 to 85 years. During the follow-up time (ranging from 5 to 17 years), 4852 CVD events occurred. Based on cohort and case-control studies, the pooled results showed no significant association between serum C-peptide with CVD events risk (RR = 1.02;95%CI:0.91-1.15, I2 = 34.7%; P-heterogeneity = 0.140). For cross-sectional studies, the pooled results indicated a positive association between serum C-peptide and the odds of CVD outcomes (OR = 1.35;95%CI:1.04-1.76, I2 = 83.6%; P-heterogeneity < 0.001).

CONCLUSIONS

The pooled results of the current study suggested that C-peptide level was not related to the risk of CVD events in cohort studies, however, the meta-analysis of cross-sectional studies showed a significant association between C-peptide and an increased risk of CVD events.

The bidirectional association of C-peptide with cardiovascular risk in nondiabetic adults and patients with newly diagnosed type 2 diabetes mellitus: a retrospective cohort study

Background

Recent literature reported the biological role of C-peptide, but this role is still controversial and unclear. The primary aim of this study was to investigate associations between C-peptide and cardiovascular biomarkers as well as events.

Methods

A total of 55636 participants who had a health examination from 2017 to 2021 were included. Of them, 6727 participants visited the hospital at least twice. Cardiovascular biomarkers like high-sensitivity C-reactive protein (hs-CRP) and high-sensitivity cardiac troponin T (hs-cTnT) were measured and their relationships with fasting C-peptide were evaluated for all participants. Cardiovascular events were obtained during the last visit and their associations with C-peptide were evaluated for those participants who visited the hospital at least twice.

Results

Among the included participants, 11.1% had a previous type 2 diabetes mellitus (T2DM). In the participants without previous T2DM, the relationships between fasting C-peptide and hs-CRP and hs-cTnT were negative if the value of fasting C-peptide was < 1.4 ng/mL and positive if the value was ≥ 1.4 ng/mL. These relationships remained significant after adjusting for hemoglobin A1c, insulin resistance index, and its interaction with C-peptide, even if the participants were stratified by glucose metabolism status or levels of insulin resistance index. Hazard ratios of cardiovascular events were first decreased and then increased with the increasing of baseline C-peptide levels, though these associations became unsignificant using the multivariate Cox regression model. Unlike the participants without previous T2DM, the associations of C-peptide with cardiovascular biomarkers and events were not significant in the patients with previous T2DM.

Conclusions

The associations of C-peptide with cardiovascular biomarkers and events were different between the participants without previous T2DM and those with previous T2DM. The effect of C-peptide on cardiovascular risk may be bidirectional, play a benefit role at a low level, and play a harmful role at a high level in the nondiabetic adults and the patients with newly diagnosed T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01636-z.

The Impact of C-Peptide and Diabetes Mellitus on Coronary Ectasia and Effect of Coronary Ectasia and C-Peptide on Long-Term Outcomes: A Retrospective Cohort Study

BACKGROUND

Coronary artery ectasia (CAE) is an entity frequently associated with atherosclerotic coronary artery disease (CAD) in clinical practice. Although it has common risk factors with atherosclerotic CAD in its development, the pathophysiology of CAE is not fully known and it is not seen in every CAD suggesting that different determinants may play a pivotal role in the development of CAD. This study aimed to reveal the impact of C-peptide and diabetes mellitus (DM) on CAE and the effect of C-peptide and coronary ectasia on long-term outcomes in patients who underwent coronary angiography.

METHODS

A total of 6611 patients who underwent coronary angiography were followed up retrospectively, and their major adverse cardiovascular event (MACE) status of an average of sixty months was recorded. According to their angiographic features, the patients were divided into two groups those with and without CAE. MACE development was accepted as the primary endpoint.

RESULTS

A total of 552 patients had CAE and MACE developed in 573 patients. Patients with CAE and higher C-peptide levels (Q4 + Q3) showed higher rates of MACE as compared to those without CAE and lower C-peptide levels (Q1 + Q2) (20.8% vs 7.6%; 70.1% vs 29.1%; p < 0.001, for both of them). In multivariate regression analysis, high C-peptide levels were determined as an independent risk factor for CAE (OR 2.417; 95% CI 2.212-2.641; p < 0.001). The Kaplan-Meier cumulative survival curves showed that the risks for MACE increased as the C-peptide levels increased. The Cox regression analysis for 5-years MACE related to the plasma C-peptide levels and presence of CAE, C-peptide, and CAE were found to be independent predictors of MACE (HR = 1.255, 95% CI: 1.164-1.336, p < 0.001 and HR = 1.012, 95% CI: 1.002-1.023, p=0.026, respectively).

CONCLUSION

Our study revealed that a high C-peptide level is an independent risk factor for CAE and that CAE and C-peptide are independent predictors for the development of MACE.