Heart rate variability in type 2 diabetes mellitus: A systematic review and meta–analysis (Published 2018)
Why I chose this topic? Cardiac autonomic neuropathy (CAN) is a common underdiagnosed complication of DM. CAN has a strong influence on MI, HTN, HF, intraoperative cardiac instability and cardiac arrhythmias and is associated with severe morbidity and mortality.
Introduction:
Diabetes is on the rise and the number of cases is expected to double within the next decade from when this article was published. Besides macrovascular and microvascular complications the leading cause of death in T2DM is cardiovascular mortality. Cardiovascular mortality in diabetics is often related to cardiac autonomic neuropathy. Heart rate variability is the gold standard to measure cardiac autonomic neuropathy.
Cardiac autonomic neuropathy can easily be assessed by measuring the heart rate variability. Heart rate variability (HRV) is the variation between two consecutive beats. The higher the variation the higher the parasympathetic activity. The HRV is an indication as to how well a person can adapt to everyday changes in their environment. There are currently no studies that assess the role of the most common variables (age, gender, blood glucose control or diabetic medications) on HRV parameters.
This study aimed to evaluate the impact of Type 2 Diabetes Mellitus on heart rate variability parameters.
Methods:
In this meta-analysis and systematic review 3,927 articles were found of which 25 met the criteria for inclusion. All of the studies included 24 hour measurements of HRV with Holter-electrocardiogram. RR intervals were analyzed along with standard deviations of the RR interval (SDNN)
Meta-analyses on the HRV parameters in T2DM and healthy pateints were conducted. The patients were between the ages of 18 and 75. Factors studied included patients with oral antidiabetic agents, hypertension, BMI over 25 or 35, chronic heart, liver or renal failure, insulin treatment, uncontrolled Type 2 Diabetes Mellitus (T2DM), thyroid disorder or treatment that can influence HRV parameters.
A total of 2,932 patients were included. 1,356 had T2DM and 1,576 healthy control patients.
Results:
Strong evidence shows that T2DM patients had significantly lower RR intervals.
Discussion:
The main findings were that that T2DM patients have a strong decrease in HRV. Both sympathetic and parasympathetic activity were decreased compared with non-T2DM pts. Dyslipdemia and HTN are also associated with a decreased HRV in T2DM. Age and male gender were associated with both a decrease in sympathetic and parasympathetic activity.
