Diabetes mellitus (DM) is a serious health issue that has escalated to concerning proportions worldwide. Inflammation is considered to be a key regulator of the pathogenesis of T2DM, but what triggers this inflammation still unknown [1]. However, it may be related to obesity. Obesity is associated with enlargement of adipose tissue and consequently increases the number of adipose tissue macrophages [2]. These macrophages are responsible for almost all adipose tissue tumor necrosis factor-α (TNF-α) expression, significant amounts of interleukin-6 (IL-6), and other acute-phase response markers and mediators of inflammation [3]. The etiology of diabetes mellitus is linked to chronic low-grade inflammation and inflammatory indicators can cause insulin resistance (IR) by speeding up apoptosis and preventing β-cell activity [4]. Thus, early blood glucose monitoring can postpone the development of diabetic vascular problems. Cardiovascular problems are more common in people with type 2 diabetes mellitus (T2DM). Diabetes-related heart problems and other vascular issues can result from persistent low-grade inflammation brought on by IR. Tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1, IL-18, total white blood cell count, and CRP (C-reactive protein) are all well-established indicators of inflammation. However, because of their expense and technological challenges, these markers are not used frequently [5].

Neutrophil-lymphocyte ratio (NLR) has recently been suggested as a new biomarker for inflammation in heart failure, SARS-COV-2 infection, and diabetic kidney disease. While lymphocytes regulate the inflammatory response and hence have an anti-atherosclerotic effect, neutrophils are focused on the release of inflammatory mediators that can lead to vascular wall deterioration. Consequently, the neutrophil to lymphocyte ratio could be used as a stand-in indicator for inflammation [6].

Likewise, it has been claimed that the platelet-to-lymphocyte ratio (PLR) represents a new biomarker for inflammation in cancer and liver illnesses. PLR shows a higher platelet count, which causes platelet aggregation and vascular problems, as well as a lower number of lymphocytes, which suggests inflammation. Systemic inflammatory response index (SIRI) and systemic immune inflammatory index (SII) have recently been proposed as inflammatory markers derived from complete blood counts (CBCs), and their levels have been linked to cancer and coronary artery disease (CAD) [7-8].

Additionally, CBC values pertaining to HDL, such as the monocyte/HDL ratio (MHR), neutrophil/HDL ratio (NHR), lymphocyte/HDL ratio (LHR), and platelet/HDL ratio (PHR), are used to compute additional inflammatory indicators. Their involvement in stroke, cardiovascular disorders and diabetic renal disease has been documented in a few investigations [9].

There is little research on the application of CBC-derived inflammatory markers in diabetes mellitus, despite the fact that NLR, PLR, SII, SIRI, and other markers have been suggested as novel biomarkers in a number of illnesses. This study also examined all CBC-derived inflammations and their relationships to HbA1c and blood sugar.

Aims and objectives

The aims and objectives of the study was to evaluate the levels of SII, SIRI, PLR, NLR and other inflammatory markers in T2DM patients as well as their relationship to HbA1c and blood sugar.

This cross-sectional study was carried out in Department of Biochemistry in a tertiary care hospital of Central India.

A total of 200 participants were chosen for the study using a straightforward random sample technique. There were 100 T2DM patients and 100 non-diabetic participants.

Inclusion criteria

Male and female participants aged ≥18 years who were willing to engage in the study were enrolled, both with and without diabetes. The American Diabetes Association's criteria were used to diagnose type 2 diabetes.

Exclusion criteria

The study excluded patients who declined to participate, those who were receiving immunosuppressive therapy, those who had autoimmune diseases, cardiovascular diseases, diabetes other than type 2 diabetes, liver, kidney, or thyroid disorders, gestational diabetics, epilepsy, hypertensive encephalopathy, cancer, or were pregnant.

Detailed physical and clinical examination was done for all the study subjects. Body mass index was calculated and blood pressure was measured in addition to the family history and lifestyle parameters.

Sample collection

Following an 8–12 hour fast, all study participants had 2 mL post-prandial and 5 mL venous blood samples taken with all the aseptic precautions. Completely automated biochemistry analyzer was used to estimate the following parameters: urea, creatinine, total cholesterol, triglycerides and HDL. Friedewald's formula was used to determine LDL and VLDL. The Fully automated Hematology analyzer (cell counter) was used to measure the CBC of EDTA samples and the Mispa I-2 analyzer was utilized to measure the HbA1c. NLR, PLR, SII, SIRI, MHR, NHR, LHR, and PHR were calculated from CBC values using the following formulas.

NLR=Neutrophil-to-lymphocyte ratio, PLR=Platelet-to-lymphocyte ratio,

SII=Platelet × Neutrophil-to-lymphocyte ratio, SIRI=Monocyte ×Neutrophil-to-lymphocyte ratio

MHR=Monocyte-to-HDL ratio, NHR=Neutrophil-to-HDL ratio, LHR=Lymphocytes-to-HDL ratio, PHR=Platelets-to-HDL ratio

Statistical analysis

The mean and standard deviation were used to represent the data, while percentages were used to communicate the categorical data. P value of less than 0.05 was deemed statistically significant. To analyze the data, SPSS was used.

In the present study, among T2DM subjects males were 54 (54%) and females were 46 (46%). In non-diabetic subjects, males were 55 (55%) and females were 45 (45%). In this study, mean age (55.9±11.4 years) was significantly high in T2DM cases than non-diabetics. Significant increase in systolic blood pressure (122.4±8.1 mmHg), diastolic blood pressure (82.2±4.8 mmHg), FBS (166.5±43.7 mg/dL), post-prandial blood sugar (236.3±48.8 mg/dL), HbA1c (8.3±2.2%), urea (29.6±8.6 mg/dL), creatinine (1.4±0.2 mg/dL), total cholesterol (192.8±46.1 mg/dL), triglycerides (178.9±61.2 mg/dL), LDL (118.0±36.3 mg/dL), VLDL (35.8±12.4 mg/dL), and neutrophil count (68.6±11.4%) was observed in T2DM cases than non-diabetic subjects. Significant decrease in HDL and lymphocytes was observed in T2DM subjects as shown in Table 1.

Table 1: Comparison of demographic details, biochemical, and hematological parameters in T2DM patients and non-diabetic subjects

In the current study, inflammatory markers such as NLR (4.4±1.3), PLR (0.18±0.01), SII (11.6±3.6), SIRI (23.7±5.2), MHR (0.15±0.08), NHR (1.8±0.72), and PHR (0.08±0.02) were significantly increased in T2DM cases than non-diabetic subjects, LHR statistically not significant as shown in Table 2.

Table 2: Comparison of inflammatory markers in T2DM patients and non-diabetic subjects

In this study, FBS was significantly correlated (positive) with SIRI (r=0.182), MHR (r=0.254), NHR (r=0.415), MHR (r=0.253), and PHR (r=0.210). Similarly, HbA1c positively correlated with NHR (r=0.351) and PHR (r=0.176). Other inflammatory markers also showed positive correlation but not reached statistical significance (Table 3).

Table3: Correlation of inflammatory markers with FBS and HbA1c

According to this study, T2DM sufferers had significantly higher levels of inflammatory markers such NLR, PLR, SII, SIRI, MHR, NHR, and PHR than non-diabetic controls. Blood sugar and HbA1c were positively correlated with inflammatory indicators. While lymphocytes show immunoregulation, neutrophils are linked to inflammation. Both innate and adaptive immunological responses, as well as systemic inflammation, may be indicated by these. Changes in peripheral blood cell counts may result from inflammation brought on by hyperglycemia [10]. Peripheral blood leukocytes and their subsets have been linked to micro and macrovascular problems in individuals with type 2 diabetes, according to prior research. More precisely, neutrophils, lymphocytes, monocytes, Eosinophils, and basophils are examples of peripheral blood leukocytes, and each type of leukocyte has a distinct biological role in systemic inflammation [11].

A study done by M. Yang, et al [12] suggests that elevated NLR could be a sign of more neutrophils adhering to endothelial cells, which damages vascular endothelium cells and causes widespread chronic inflammation. Therefore, in patients with type 2 diabetes, a higher NLR may suggest increased microvascular inflammation. The body's immunological response is mostly mediated by lymphocytes. They have a comparatively greater percentage of CD4 T cells that have been shown to be anti-atherosclerotic, and they play a role in controlling inflammatory responses [13].

Likewise, PLR is markedly elevated in individuals with type 2 diabetes. According to Donath MY, et al [14], PLR has a part in predicting atherosclerosis, diabetic foot ulcers, and lower limb vascular disease linked to diabetes.

The role of platelets in thrombosis is well established. According to Hallan SI, et al [15] and S. Cinti, et al [16], platelets are important for the immuno-inflammatory response. In particular, platelets have the ability to release a range of chemokines, immune-regulating cytokines, and other mediators, which can either autocrinely or paracrinely, control the inflammatory response in blood vessels. In the meantime, platelets may also directly control lymph, endothelial cells, and neutrophils, enabling them to migrate toward damaged tissue. Because platelets have this regulating role, higher PLR may be a sign of a rather active inflammatory response in T2DM patients [17]

A research performed by A. Festa, et al [18] suggested that the SII and SIRI are new inflammatory markers generated from CBC. Research has documented a correlation between SIRI, SII, and problems related to diabetes. Given some of the mechanisms underlying the development of diabetes and related complications, the correlation between SII and diabetic vascular problems is not surprising.

The pathophysiology and development of diabetes are significantly influenced by inflammation and the immune system. In particular, tissue damage and organ malfunction brought on by persistent low-grade inflammation can exacerbate insulin resistance and decrease insulin secretion. Our findings are consistent with research by M.

Yang et al [12].and P. Marques, et al [19].

According to reports, MHR is a new biomarker that combines anti-inflammatory and pro-inflammatory indices. Diabetic vascular problems are significantly influenced by monocytes. There is evidence linking monocyte numbers to vascular problems, T2DM, and IR [20]. However, new research suggests that decreased HDL has a significant role in hastening atherosclerosis in diabetics. Therefore, in diabetes individuals, the integrated maker, MHR, may be a better marker to show vascular inflammatory alterations. Patients with type 2 diabetes also had considerably higher levels of NHR and PHR in addition to the inflammatory markers mentioned above.

Limitations of the study

 Due to limited  resources available, there was no assessment of well-known inflammatory indicators like CRP and IL-6.

As alternative indicators of inflammation, the study may conclude that elevated levels of NLR, PLR, SII, SIRI, MHR, NHR, and PHR in T2DM, along with their positive connection with blood sugar and HbA1c, may be present. These markers are less costly and can be simply computed from CBC values. As a result, these easy-to-use and affordable indicators are helpful in evaluating how the systemic inflammatory response affects patients with type 2 diabetes. More comprehensive studies should also be conducted to evaluate NLR, RDW, MPV, PLR, MLR and MHR parameters in albuminuria that may occur due to renal damage in patients with diabetes.

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