Evaluation of Microvascular Complications in Kidney Recipients with Post-Transplant Diabetes Mellitus

CONTEXT

Limited data on microvascular complications in patients with post-transplant diabetes (PTDM) is an obstacle to developing follow-up algorithms.

OBJECTIVES

To evaluate diabetic microvascular complications in patients with long-standing PTDM.

METHODS

This study included patients with at least a five-year history of PTDM and age-matched renal transplant recipients without PTDM (NDM). Diabetic peripheral neuropathy (PN) was evaluated using the Michigan Neuropathy Screening Instrument (MNSI), the CASE IV device, and in vivo corneal confocal microscopy (CCM). Cardiac autonomic neuropathy (CAN) tests were performed using the heart rate variability. Nephropathy (DN) screening was assessed using spot urine albumin/creatinine ratio and eGFR calculation. Diabetic retinopathy (DR) was evaluated by fundus examination and photography, and optical coherence tomography.

RESULTS

This study included 41 patients with PTDM and 45 patients in the NDM group. The median follow-up was 107.5 months in the PTDM group. PN was significantly higher in the PTDM group than in the NDM group (p = 0.02). In the PTDM patients with PN, the corneal nerve fiber density examined by CCM was significantly lower than in the PTDM patients without neuropathy (p = 0.001). Parasympathetic involvement was observed in 58.5% of the PTDM group and 22% of the NDM group (p = 0.001). Sympathetic involvement was present in 65.9% of the PTDM group and 29.3% of the NDM group (p = 0.001). Retinopathy was observed in 19.5% of patients in the PTDM group, while none were in NDM patients (p < 0.001). Renal functions were similar between the study groups.

CONCLUSIONS

CAN and DR can affect patients with PTDM at a high rate. DR was found to be a threat to the vision of PTDM patients. Diabetic PN can be detected early in PTDM patients by CCM.

QTc prolongation in Black diabetic subjects with cardiac autonomic neuropathy

BACKGROUND

Prolonged corrected QT (QTc) has been identified as a risk factor for malignant arrhythmias and sudden cardiac death. Caucasian studies have shown a definite relationship between QTc prolongation and Cardiac Autonomic Neuropathy (CAN) in diabetic subjects.

OBJECTIVE

To determine the prevalence of prolonged QTc in Black diabetic individuals with CAN and to ascertain how prolonged QTc correlated with the severity of CAN among these patients.

METHODS

A total of 176 adult diabetic subjects were studied, 87 males and 89 females. There was a control group of non-diabetic individuals. Cardiac autonomic function was assessed using five cardiovascular autonomic function tests. CAN was diagnosed if 2 or more of these tests were abnormal. Severity of CAN was determined according to the number of abnormal tests. QTc > 0.440 was regarded as prolonged.

RESULTS

Fifty-one out of the 176 diabetic subjects (29%) had CAN. The prevalence of prolonged QTc in diabetic subjects with CAN was 12%. QTc was prolonged in 1.6% and 0.6% of diabetic individuals without CAN and controls respectively. Although QTc correlated strongly with cardiac autonomic function neuropathy, there was no definite relationship between QTc prolongation and severity of CAN.

CONCLUSION

This study in a Black population is in agreement with the well-known relationship between QTc prolongation and CAN reported in Caucasian studies. In view of the wide variability of QTc in this study population, it is suggested that relative QTc increase may be a better indicator of CAN than a definite QTc prolongation of greater than 0.440.

Potential Association of Triglyceride Glucose Index with Cardiac Autonomic Neuropathy in Type 2 Diabetes Mellitus Patients

Cardiac autonomic neuropathy (CAN) is a common and most neglected complication of diabetes, estimated to be roughly 8% in recently diagnosed patients and greater than 50% in patients with chronic disease history. The insulin resistance (IR) itself is bidirectionally associated with increased risk of type 2 diabetes mellitus (T2DM) and CAN is a predisposing factor. The primary objective of the present study was aimed to find a correlation of triglyceride glucose index (TyG index) in CAN patients along with the prevalence of CAN in T2DM patients as a secondary objective. This prevalence study was conducted on 202 patients visiting the diabetic clinic of Hamdard Institute of Medical Sciences and Research, Jamia Hamdard (HIMSR) teaching hospital in New Delhi, India who fulfilled the inclusion criteria. The Ewings autonomic function test was used for diagnosis of CAN. TyG index was calculated for patients based on fasting levels of glucose and triglyceride. The CAN was diagnosed in 62 participants out of 202 T2DM patients (overall prevalence 30.7%). The mean ± standard deviation (SD) for TyG index was 10.3 ± 0.2 and 9.5 ± 0.2 in CAN positive, T2DM patients, respectively. The difference of TyG index, in CAN positive and T2DM patients, was highly significant (P < 0.001). Further correlation analysis was performed to find an association of TyG index, duration, and age with patient groups. TyG index showed a positive correlation with heart rate during deep breathing (HRD), heart rate variation during standing (HRS), blood pressure (BP) response to handgrip and BP response to standing. Our finding highlights the TyG index, low-cost IR index, might be useful as an alternative tool for the early screening of patients at a high risk of diabetic neuropathy.