Diabetes Mellitus Type 2 And Red Blood Cell Distribution Width

University of Medicine and Pharmacy ‘Iuliu Hatieganu’

Cluj-Napoca

Faculty of Medicine

LICENCE THESIS

Diabetes Mellitus type 2 and Red blood cell distribution width.

Coordinator:

Dr. Ciobanu Dana Graduate:

Naji Mooshta

Introduction

Diabetes Mellitus (DM) is a chronic metabolic disorder which can effect people in all age groups and in all stages of life. Everyday life is greatly affected for those who get the disease, and the treatment requires that the individual daily can make important and complex judgments and choices. Key goals of diabetes care is to help people with diabetes to maintain an optimal blood sugar levels and prevent complication. The general recommendations include screening, diagnostic, and therapeutic actions that are recognized or believed to favourably affect health outcomes of patients with diabetes. Large number of these interventions have also been shown to be cost effective.

The prevalence of diabetes is increasing in the world, specially for type 2-diabetes. It is partly linked with increasing age and a near epidemic development of overweight and obesity, which contributes to increasing insulin resistance.

Red blood cell distribution width (RDW) is a marker associated with morbidity and mortality in population with cardiovascular diseases. The aim of this study is to investigate the effect of diabetes type 2 (DT2) on RDW level and if there is any association between RDW, neuropathy, nephropathy and peripheral arterial disease (PAD) in DM patients. Nonetheless, there has been little data on the relationship between diabetes-associated complications and RDW.

Definition

Diabetes mellitus is a group of metabolic diseases characterized by chronic hyperglycaemia as a result of defects in the secretion and / or insulin action. They are accompanied by changes in lipid and protein metabolism, with some disturbances in minerals and electrolytes. All having as consequences, structural alterations of many organs by the appearance of acute or chronic complications.

The most common type of diabetes is type 2 DM which makes around 90% of all Diabetes cases. Unfortunately, diagnosis is usually delayed until appearance of the complication. Management of the disease is mostly aimed at lifestyle changes, diet modifications, and glucose lowering medications or insulin treatment. A good treatment of hyperglycaemia and associated disorders (especially obesity, dyslipidaemia and hypertension) can significantly reduce the risk for complications. (1)

RDW is a measure of variation in red blood cell size (anisocytosis), and is routinely assessed as part of standard clinical work-up of anemia and complete blood count. RDW can be elevated in situation causing a increased of either small or large red blood cells, in comparison to the patients average red cell volume. Elevated RDW has been correlated with cardiovascular mortality as well as in patients with heart failure. The association between RDW and patients mortality is until now unknown.

Classification of diabetes

A. Type 1 diabetes mellitus (type 1 DM) or previously called insulin-dependent diabetes, juvenile-onset diabetes in children, comprises 5-10% of all patients with diabetes and occurs through absolute insulin deficiency, due to destruction of pancreatic cells (β cells) secreting insulin. This is the most common form of diabetes with the onset before 35 years of age, although onset may be at any time in life and even in obese people. Latent autoimmune diabetes of adults (LADA Latent Autoimmune Diabetes in Adults = Late-onset Autoimmune Diabetes or of Adulthood) called slow-onset T1D is an adult-onset diabetes and slowly progressive to total insulin deficiency.

Type 1 diabetes mellitus has a multifactorial etiology and describes in two subtypes:

a) Autoimmune: beta cells of the pancreas are destroyed by the autoimmune mechanisms and the markers of autoimmune process are represented by autoantibodies: Islet Cell Cytoplasmic Autoantibodies (ICA), Insulin Autoantibodies (IAA) Glutamic Acid Decarboxylase (GAD65), Insulinomaassociated-2 Autoantibodies IA-2 and IA-2β. Histological examination of the pancreas from an patient with type 1 diabetes showed a chronic inflammatory mononuclear cell infiltrate of CD4+ and CD8+ T lymphocytes and macrophages in the islets (insulitis).

b) Idiopathic: In this case we do not identify autoantibodies that lead to beta cell destruction, the mechanisms of this type of diabetes remaining unknown. This type of diabetes is greatly inherited, absence immunological evidence for b-cell autoimmunity, and is not HLA associated. A complete requirement for insulin therapy in affected patients may come and go. (5)

B. Type 2 diabetes (T2D) formerly known as non insulin dependent diabetes or adult-onset diabetes which includes 90-95% of patients with diabetes, occurs mostly after the age of 40, caused by a combination of genetic and lifestyle factors. The onset can occur at younger ages, obesity contributes strongly to earlier onset. T2D associate in varying degrees, defects in insulin action (insulin resistance) and reducing pancreatic secretion of insulin (insulin secreting deficiency). (4)

Type 2 diabetes occurs in families and is polygenic mode of transmission is involved mutations in genes encoding insulin, mitochondrial components, insulin receptor, glucokinas, glycogen synthase etc. Type 2 diabetes is a disease that is increasing worldwide. By changing diet and exercise habits, the disease can be delayed or prevented. Changing lifestyles can perceive as a requirement, it may be difficult for the person to find motivation change. Most diagnosed patients with this type of diabetes are overweight, and obesity by itself causes to some degree of insulin resistance. In subjects who are not obese by traditional weight criteria may have an elevated percentage of body fat distributed predominantly around the abdominal region.

Specific types of diabetes:

Genetic defects of beta cells in the pancreas: They are characterized by impaired insulin secretion with minimal or no defects in insulin action.

Genetic defect of the mechanism of action of insulin; type A insulin resistance, leprechaunism, Rabson-Mendenhall syndrome, lipoatrophic diabetes etc.

Diseases of the exocrine pancreas: chronic pancreatitis, pancreatectomy, cystic fibrosis, hemochromatosis, neoplasm, etc.

Endocrinopathies: acromegaly, Cushing's syndrome, hyperthyroidism, pheochromocytoma,

glucagonoma, somatostatinoma etc.

Drug- or chemical-induced diabetes: glucocorticoids, thyroid hormones, diazoxides, thiazide diuretics, α-interferon, nicotinic acid, vacor, pentamidine, β-adrenergic agonists, dilantin other;

Infections: congenital rubella, cytomegalovirus, mumps, infectious mononucleosis etc.

Genetic syndromes: Down syndrome, Klinefelter syndrome, Turner syndrome, Wolfram syndrome, Friedreich ataxia syndrome, Laurence-Moon-Biedl syndrome, Prader-Willi, porphyria, myotonic dystrophy etc.

Gestational diabetes mellitus (GDM)

Gestational diabetes is a temporary form of type 2 diabetes. During pregnancy the body is subjected to extreme loads, including deteriorating body sensitivity to insulin. Normally, increasing the pregnant woman's body insulin production to compensate. If the body is unable to produce enough insulin, increases blood sugar in circulation and finally hit the woman of so called gestational diabetes. To decrease side effects to the fetus, the future mother most be treated. Fetal complication is associated with an increased risk of fetal macrosomia, congenital abnormalities, intrauterine fetal death and other complications.

The risk of gestational diabetes increases if one has diabetes in the family, have had gestational diabetes earlier or had a baby who weighed more than 4.5 kg. The risk also increases in population with overweight. The GDM which usually goes over after childbirth, increasing the risk of developing type 2 diabetes later in life. The women with gestational diabetes should continue to be checked the following years after delivery.

Epidemiology of Diabetes

Diabetes is a big global health problem and from 382 million people with diabetes most of them are aged between 40 and 59, and approximately 80% of them live in low- and middle-income countries. Diabetes type 2 estimate for 85% to 95% of all diabetes and the number are increasing mostly due to rapid cultural and social changes: as well as ageing populations, increasing urbanisation, dietary changes with fast foods, reduced physical activity and unhealthy behaviours. Diabetes is the fourth or fifth leading cause od death in most high-income countries worldwide.

As a consequence, diabetes in all its forms imposes high human, social and economic costs on the countries at all income levels. Even if diabetes type 1 is less common, is increasing for every year in both rich and poor countries. In most developed countries, the majority of children and adolescents with diabetes are type 1. (8)

The diagnosis of diabetes ,

Clinical stages of diabetes mellitus

The clinical staging of diabetes differs through multiple stages during its natural curs and that individual may move from one stage to another in either direction (see Fig.1). Initially, glucose levels are normal and no abnormality can be identified in blood glucose even if these individuals undergo an oral glucose tolerance test (OGTT). This stage is followed by a period of variable duration in which glucose regulation is impaired. They may have some abnormality of the fasting glucose concentration (IFG), or if they receive an OGTT, they may demonstrate impaired glucose tolerance (IGT). Patients may revert to having impaired glucose regulation or even normal glycaemia. This is seen most frequently in patients with recent-onset type 2 diabetes, in whom lifestyle intervention and/or early aggressive treatment may result in apparent reversal of the abnormality with reversion to impaired or normal glucose tolerance. This may also be seen in type 1 diabetes, in which after a short period of insulin treatment, there may be a variable period when insulin is no longer required for survival and glucose tolerance may improve—the so- called honeymoon period. Eventually such patients do need insulin treatment for survival.

Many women who have had gestational diabetes develop diabetes within a few years when they are not pregnant; thus, even in the face of normal glycemia, such women can be recognized as being at high risk of developing type 2 diabetes.

IFG and IGT are metabolic intermediary stages between normal glucose homeostasis and diabetes. IFG and IGT are not synonymous and may represent different abnormalities of glucose regulation, although they may occur together. Individuals with either of these states of impaired glucose regulation have a high risk of progressing to diabetes.

A: Clinical diagnosis

Type 2 diabetes has a gradual and insidious onset, with nearly one-third of cases identified as an incidental finding. Around 50% of people with type 2 diabetes are diagnosed as a result of the typical diabetic symptoms, the most common signs and symptoms are:

polyuria (diuresis >2000 ml / 24 hours) produced by osmotic mechanism;

increased sensation of thirst and polydipsia due to hyperosmolar state;

weight loss (result of exaggerated protein and lipid catabolism and dehydration). Weight loss is more common in type 1 diabetes and may be moderately or highly expressed (10-20 kg in a few weeks or months);

fatigue, decreased physical and intellectual labor, blurred vision;

polyphagia accompanies some cases of type 1 diabetes onset;

signs of infectious and degenerative complications (cystitis, vulva, mycosis skin, numbness and pain in the limbs, skin ulceration to gangrene etc.).

advanced stages, symptoms of diabetic ketoacidosis coma, more frequently in T1D

B. para-clinical diagnosis

Laboratory determinations made in diabetes:

plasma glucose (venous blood), collected during fasting (on an empty stomach, at least 8 hours after the last meal) or at any time of the day;

oral glucose test tolerance (OGTT): Venous blood for determination of fasting glucose; immediately after the subject will ingest a solution of 75 g of glucose dissolved in 300 ml of water (concentration 25%) within 5 minutes; after two hours will repeat dosing plasma glucose.

glycosylated haemoglobin HbA1c: is considered the gold standard for glucose monitoring; It is expressed as a percentage of total haemoglobin (normal: 4.6%). HbA1c reflects average blood glucose levels over a period of 2-3 months earlier.

C. Criteria for diagnosis of diabetes

HbA1c≥ 6.5%. The test must be performed in a laboratory using standard methods recognize. 

or

Fasting glucose ≥126 mg% à (7 mmol / L) – harvesting is done without the patient eat foods with at least 8 hours before.

or

The blood sugar levels during a 2-hour OGTT ≥200 mg% (11.1 mmol / L).It is recommended that the tests be redone under the same conditions, to exclude any laboratory errors that may appear. or

Symptoms of diabetes plus glucose at any time of the day ≥200 mg% (11.1 mmol / L

Diabetes mellitus treatment

Non pharmacological treatment

Patient Education: Study shows how a 12-month care training improved self-efficacy and self-care behaviour as regards diet and exercise in people with diabetes type 2. Participants in the study were first learn to analyse and understand their condition by providing knowledge about the disease and self-care.

Diet: In order to maintain the levels of glucose in the blood at a constant level, it is important for people with diabetes to eat a healthy balanced diet, poor on white sugar and cholesterol. In addition, weight loss provides both improved glucose control and reduction of insulin resistance.

Physical activity: Patients should be encouraged to take moderate exercise for at least 30 min/day. Increased physical activity has been shown to lead to prolonging insulin action, sustained improvement in glycaemic control and insulin sensitivity, reducing cholesterol LDL and triglycerides, increased HDL cholesterol and there is a link between regular physical activity and reduced risk of cardiovascular disease.

Pharmacological treatment

There are several diabetes drugs that can be taken in tablet form, simplified can be divided into drugs that stimulate pancreas insulin production and drugs that increase the body's sensitivity to insulin, thus enhances the effects of body insulin produces.

Metformin: is a Biguanides which decrease glucose level in the blood by reduction in glucose formation in the liver through activation of AMP-activated protein kinase but also by increasing glucose uptake in muscle. Usually first line of treatment after diagnosis and it is contraindicated in DT1, liver disease, renal insufficiency.

Thiazolidinediones: are peroxisome proliferator-activated receptor γ modulators; they enhance the receptor sensitivity of muscle, fat, and liver to circulating insulin. The most common side effects are increase in weight and fluid retention, with peripheral edema, increased risk for congestive heart failure and elevated incidence of fractures in women and perhaps in men.

Sulfonylureas and meglitinides : This medications increase insulin secretion by stimulating pancreas. The efficacy of this drugs depends largely on beta cells capacity to produce insulin, therefore only efficacious in the early years of evolution of the type 2 diabetes when there is still endogenous insulin.

Alpha-glucosidase inhibitor: inhibit the alphaglucosidase enzyme which catalyzes degradation of polysaccharides to absorbable monosaccharides in the proximal small intestine. Intake before meals leads to a slow and reduced glucose uptake which decrease blood glucose levels after meals.

GLP-1 analogs (exenatide, liraglutide) : inhibits the glucagon production α-cells of the endocrine pancreas, resulting in a reduction formation of glucose in the liver.

DPP-4 inhibitors (sitagliptin, vildagliptin, saxagliptin): inhibiting the DPP-4 enzyme (Dipeptidyl peptidase-4), which means that the plasma concentration of native GLP-1 increases. Similar effect as GLP-1 analogs.(10)

Insulin – is the oldest and still the most important and effective medicine for diabetes. Insulin can only be given by means of syringes. There are different types of insulin that can be fast-acting and long-acting or pre-mixed insulin containing a combination of the two varieties. What type of insulin and how many doses per day required will depend on the current clinical picture of the disease and the target treatment which the doctor and the patient agreed upon.

Pancreas transplantation – The transplantation of pancreas or islet is the only therapy to date which can be said to cure diabetes. Unfortunately, the low number of donor pancreas, high cost of the operation and the need for immunosuppressive therapy for the entire lifetime, greatly limits the expansion of this procedure compared with large and growing number of patients with DM. It is usually carried out in association with renal transplantation in patients with DT1, very difficult balancing stage diabetic nephropathy and chronic renal insufficiency.

Diabetic Complications

Acute Complications:

Hypoglycaemia, ketoacidosis or coma may occur if the disease is not controlled.

Diabetic ketoacidosis (CAD) is a metabolic emergency caused by a severe deficiency or absolute insulin. The deficiency of insulin causes hyperglycaemia (> 250mg / dl), which, along with lipolysis, respectively increased production of ketone bodies, leading to metabolic acidosis and electrolyte imbalance. Occurs most frequently in patients with type 1 diabetes who for various reasons have not received their insulin or the amount has been too small.

Status without ketoacidosis hyperosmolar is a frequent complication in type 2 diabetes, especially in adults and the elderly. It is defined by the absence of significant ketoacidosis in a patient with plasma osmolality hyperglycemic or mixed (hyperglycaemic and hypernatremia).

Lactic acidosis is a rare complication, but showing a mortality of 30%. Increase in plasma lactate is defined by more than 5 mEq / L, associated with a drop in pH below 7.25. It occurs due to a shortage of lactic dehydrogenase, along with a defective tissue oxygenation and injuries due to the macro and microangiopathy.

Chronic Complication:

Diabetes in various forms leads to an increased morbidity risk of early death, as a result, the life expectancy of a person with type 1 diabetes, shortened by about 10 years compared to a non-diabetic person. Furthermore, a 5-year mortality for a person with newly diagnosed type 2 diabetes by about 40 percent.

Nephropathy

Diabetic nephropathy is the major cause of end-stage renal failure in developed countries. This condition is represented by progress of proteinuria with a following decrease in glomerular filtration rate, which advance over a long period of time, usually over 10-20 years. If the condition left untreated, the emerge uremia is fatal and can requiring dialysis or kidney transplantation.

Neuropathy

Almost more than half of all patients who have diabetes sooner or later develop neuropathy which encompasses both the autonomic and somatic pathways of the peripheral nervous system. In severe neuropathy due to nerve degeneration in diabetes; is characterized by modified sensitivities to vibrations and thermal thresholds, which develop to loss of sensorial perception. This pathology includes a loss of sensation after a injury leading to callouses and some other commonly foot injuries which put individuals with diabetic neuropathy at high risk of getting foot and leg ulcers, with a high risk of end stage amputation.

In addition to autonomic dysfunction the individuals with diabetes have orthostatic hypotension, caused by inability to adjust heart rate and vascular tone to maintain blood pressure. The situation also involving gastrointestinal tract which leading to gastroparesis, nausea, bloating and diarrrhea , which can effect the oral medications.

Retinopathy

Diabetic retinopathy is defined by a spectrum of lesions inside the retina and is the most cause of blindness among adults aged between 20-74 years. This changes in the eyes include vascular permeability, capillary microaneurysms, capillary degeneration, and excessive formation of new blood vessels. Diabetic retinopathy develops over many ears as much as 20 years in patient diagnosed with diabetic.

In addition to control glycemia and maintaining blood pressure, there are some treatments that have benefits in reducing vision loss. These treatments include laser photocoagulation, injection of the steroid triamcinolone and new approved vascular endothelial growth factor(VEGF) antagonist into the effected eye, and vitrectomy to remove vitreous.

Cardiovascular disease

In diabetic population the risk of cardiovascular disease (CVD) like myocardial infarction is equivalent to that of non-diabetic patients who in the past had a myocardial infarction. CVD in diabetes include premature atherosclerosis leading to infarction and stroke as well as cardiac failure, predominantly diastolic dysfunction. Half of the mortality seen in the diabetic individuals are due to CVD.

Red blood cell distribution width.

Erythrocytes

Red blood cells are produced in the bone marrow and are the cells in our blood that supplies oxygen to the body tissues. They have a diameter of about 7 microns which is needed to carry out a proper gas exchange in tissues by passage microcirculation, whose smallest diameter is 3.5 microns. This is possible because of the erythrocyte biconcave shape and the erythrocytes are able to generate energy in the form of adenosine triphosphate (ATP). Every day it is produced new red blood cells in our body. This process is called erythropoiesis and is strictly regulated, they must be replenished in precise number by a continuously renewing population of progenitor cells. Normal erythropoiesis also depends upon an adequate dietary supply of iron, folic acid, and cobalamin (the active form of vitamin B12).

Erythropoiesis matures through many different steps, from stem cell to pro-erythroblast, polychromatic, Orthochromatic, reticulocyte and on to the mature erythrocyte. Pro-erythroblast is a large cell that is colored dark blue in the May-Grünwald – Giemsa staining. Pro-erythroblast has a centered core and produce less cells whose haemoglobin content gradually increases. A single pro-erythroblast usually give rise to a mature erythrocyte 16. While haemoglobin content increasing in stages after pro-erythroblast cell decreases its RNA content and protein synthesis, cell chromatin condenses even more and more. When the cell has finally left erythroblasts stage a reticulocyte is formed, which still contain some RNA, and still can produce haemoglobin. An erythrocyte contains about 640 million haemoglobin molecules.(32)

In adult haemoglobin consists most molecules of haemoglobin A (α2β2) but also the haemoglobin F (α2γ2) and A2 (α2δ2) are minor. The haemoglobin produced in mitochondria by a series of biochemical reactions where four globin chains with a home group each form a haemoglobin molecule.

The rate of erythropoiesis is primarily controlled by the positive effect of the erythropoietin (EPO) on erythroid progenitors in the bone marrow. EPO is a glycosylated protein primarily produced by peri-tubular fibroblasts in the renal cortex, but can also be formed by the liver. The production of erythropoietin, stimulated by reduced oxygen pressure in the renal tissue, for example, anemia due to a reduction in the number of erythrocytes. Erythropoietin stimulates erythropoiesis in two steps before pro-normoblast stage, at late Erythroid burst forming units (BFU-E) and the Colony Forming Units-Erythroid (CFU-E) progenitor cells each having Erythropoietin. (32)

Erythropoietin stimulates BFU-E and CFU-E the proliferation, differentiation and haemoglobin production. A burst in EPO-induced erythropoiesis is followed 3-4 days later by an increased number of reticulocytes in peripheral blood. When the oxygen pressure increases in the renal tissue it reducing erythropoietin production. Measurement plasma EPO can be a valuable parameter in clinical diagnosis. Although erythropoietin is a very important part of erythropoiesis, several other precursors requires for a effective erythropoiesis. Adequate dietary supply of example metals such as iron and cobalt, vitamins (especially vitamin B12, folate, vitamin C, E, B6, thiamine and riboflavin) and androgens hormones and thyroxin. Anaemia can be due to lack of any of these.

Red blood cell distribution witth.

Red blood cell distribution width (RDW) is a quantitative measure of the size variations of circulating erythrocytes. RDW is used with mean cell volume (MCV) at anemia investigation and also routinely assessed as part of a standard complete blood count. RDW is calculated as the size of the variation in the percentage of erythrocyte mean cell volume (MCV).

With the help of the RDW and MCV can divide anemias of various types; microcytic, normocytic or macrocytic all of which have either high or low RDW. In pathological conditions RDW is increased and this increase occurs before changes in both the level of hemoglobin and MCV can be seen. RDW is an important parameter for early detection of deviations from the normal red blood count.

In iron, folate and vitamin B12 deficiency anemia, the level of RDW have been seen increased; it is linked to defective erythropoiesis or erythrocyte degradation.(15) Increased RDW levels have also shown to be correlated with higher cardiovascular mortality in the general population and with elevated cardiovascular mortality and morbidity in people with diagnosed heart failure and coronary artery disease (CAD).

RDW levels is recognised as a prognostic marker that mirror oxidative stress and chronic inflammation in population with cardiovascular disease. Diabetes mellitus is a chronic condition define by higher oxidative stress and vascular inflammation with subsequent increased atherosclerosis and accelerated cardiovascular morbidity and mortality. Elevated level of RDW is seen in pre-hypertensive and hypertensive patients when compared with normotensive patients. It is recognized that hypertensive patients can be divided into two classes based on 10% reduction in the nocturnal blood pressure patterns: dipper and non-dipper hypertensive. Non-dipper hypertensive patients bear much higher cardiovascular risk and has more chance to get subclinical target-organ damage compared with dippers due to higher oxidative stress. Early identification of those subjects are important, as they are at higher risk of adverse cardiovascular events.

National Health and Nutrition Examination Survey (NHANES) have demonstrated that increased RDW levels are correlate with higher risk of myocardial infarction, heart failure, stroke and nephropathy in a nationally representative sample of USA patients with DM; the chance of getting retinopathy were not significantly increased.

In this study we will therefore evaluate if there is any significant and independent association of RDW with diabetic neuropathy, diabetic nephropathy and peripheral arterial disease in a type 2 diabetic patients in long durations.

References