Introduction
Diabetes is a chronic complex metabolic disorder leading to impaired glucose tolerance and hyperglycemia, which in turn lead to end organ failure. As per the WHO report, every year about 422 million people have diabetes and 1.5 million deaths are directly due to diabetes (1). Both diabetes and cardiovascular diseases are characterized by subacute inflammation and resistance to insulin. Under the stimulus of various risk factors, it is evident that in the natural pathway of diabetes, inflammatory mediators play a major role (2).
Atherosclerosis is an inflammatory disease of the arteries, occurring as a result of arterial wall lesions, due to lipid retention in the intima and hence classically associated with altered lipid metabolism and hypercholesterolemia (3). Atherosclerotic cardiovascular events are among the major cause of illness, complications, and death among diabetic individuals.
Carotid Intima media thickness, being simple and non-invasive, is widely used as a marker of atherosclerosis as it can identify early atherosclerotic vascular changes (4). The thickness of intima and media can signal the presence of atherosclerosis (plaque buildup) even in its earliest stages even before any symptoms develop. As atherosclerosis advances, risk of cardiovascular disease increases. Thus, CIMT helps in early identification and in planning preventive measures (5).
TSH aggravates atherosclerosis by promoting macrophage inflammation within plaques (6). Insulin sensitivity, development of chronic complications in diabetes, as well as alteration in glucose metabolism could be attributed to abnormal thyroid function, and likewise, diabetes itself can alter thyroid function by impairing peripheral conversion of thyroxine and altering thyroid stimulating hormone (TSH) (7, 8). Hence, diabetes and its complications could be associated with abnormal thyroid function test. So this study was conducted to find the relationship between TSH and CIMT in diabetic patients. Early identification of the risk factors will help us in preventing disease progression and reducing mortality.
Objective
To study the correlation between CIMT and TSH in diabetic individuals.
Materials and methods
In this hospital-based analytical cross-sectional study, 29 diabetic patients attending General Medicine OPD of Sree Gokulam Medical College and Research Foundation, Trivandrum, for a period of 2 weeks from February 17/2/2024 to 29/2/2024 were selected using Consecutive sampling and after getting informed written consent. We excluded patients with recent hospitalization for the last 2 weeks, history of thyroid surgery, use of thyroxine preparation and other drugs affecting thyroid function, and also patients with underlying liver or kidney disease and history of coronary artery disease. A detailed pro forma was filled out for each patient, which included age, sex, CIMT, and laboratory parameters, including FBS, HbA1c, and TSH. CIMT was measured using B mode ultrasound at common carotid artery. According to the European Society of Cardiology (ESC), CIMT values greater than 0.90 mm are considered to be indicative of organ damage (9). Blood samples were taken and TSH value was determined by the chemiluminescence method, and normal TSH was taken as 0.5–5 MIU/L (10). The collected data were entered into the SPSS statistical data package and the correlation between TSH and CIMT was done using Pearson correlation analysis.
Results
34.5% of study population were female while 65.5% were male (Table 1). The various patient characteristics are mentioned in Table 2. The mean age was 66.32 + 10.981. The maximum HbA1c was 12 with a mean 7.65. 55% had CIMT more than 0.9 mm (Figure 1), the mean CIMT was 1.0345, with maximum value of 2.10. Table 3 shows the correlation between CIMT and various parameters. A positive correlation was found between CIMT with FBS and HbA1C with p < 0.001, with r-value 0.812 and 0.709, respectively. We found a negative correlation between CIMT and TSH r – 0.213 with a p-value 0.267 (Figure 2). All patients were euthyroid and mean TSH was 1.316.
Table 1. Distribution of cases according to gender.
Table 2. Descriptive statistics.
Figure 1. Distribution of cases according to CIMT.
Table 3. Correlation between CIMT and age, FBS, HbA1C, and CIMT.
Figure 2. Correlation between CIMT and TSH.
Discussion
Carotid Intima media thickness was greater in patients with high FBS and uncontrolled diabetes. All subjects were euthyroid. We found a negative correlation between CIMT and TSH r – 0.213 with a p-value 0.267. In a study done by Jie Lin et al. (6), Zhou et al. (11) it was shown that CIMT was inversely associated with thyroid function test, P-values ≤ 0.002. Even though in patients with normal thyroid function many studies have found a positive correlation between TSH and CIMT (12), we couldn’t establish such a relationship. In a study conducted by Monzani et al., it was found that patients with subclinical hypothyroidism had significantly higher mean CIMT than euthyroidism controls (r = 0.71, P < 0.0001) (13). No interaction between diabetes and subclinical hypothyroidism was detected using CIMT in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) (p = 0.29) (13).
Carotid Intima media thickness can be used as marker for detecting early atherosclerosis in diabetic patients. Since no correlation was found between CIMT and TSH in our study, the role of TSH in predicting atherosclerosis in diabetic patients could not be established. Studies with a larger sample size need to be carried out to establish the relationship.
Conclusion
Diabetes was found to be associated with early atherosclerotic changes measured using CIMT. However, no association was found between TSH and development of atherosclerosis in diabetic patients measured using CIMT. This cross-sectional study does not establish any relationship between CIMT and serum TSH.
References
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