The term diabetes includes several different metabolic disorders that all, if left untreated, result in abnormally high concentration of a sugar called glucose in the blood. Diabetes mellitus type 1 results when the pancreas no longer produces significant amounts of the hormone insulin, usually owing to the autoimmune destruction of the insulin-producing beta cells of the pancreas. Diabetes mellitus type 2, in contrast, is now thought to result from autoimmune attacks on the pancreas and/or insulin resistance. The pancreas of a person with type 2 diabetes may be producing normal or even abnormally large amounts of insulin. Other forms of diabetes mellitus, such as the various forms of maturity onset diabetes of the young, may represent some combination of insufficient insulin production and insulin resistance. Some degree of insulin resistance may also be present in a person with type 1 diabetes.
The main goal of diabetes management and control is, as far as possible, to restore carbohydrate metabolism to a normal state. To achieve this goal, individuals with an absolute deficiency of insulin require insulin replacement therapy, which is given through injections or an insulin pump. Insulin resistance, in contrast, can be corrected by dietary modifications and exercise. Other goals of diabetes management are to prevent or treat the many complications that can result from the disease itself and from its treatment.
The treatment goals are related to effective control of blood glucose, blood pressure and lipids, to minimize the risk of long-term consequences associated with diabetes. They are suggested in clinical practice guidelines released by various national and international diabetes agencies.
The targets are:
- HbA1c of less than 6% or 7.0% if they are achievable without significant hypoglycemia
- Preprandial blood glucose: 3.9 to 7.2 mmol/L (70 to 130 mg/dl)
- 2-hour postprandial blood glucose: <10 mmol/L (<180 mg/dl)
Goals should be individualized based on:
In older patients, clinical practice guidelines by the American Geriatrics Society states "for frail older adults, persons with life expectancy of less than 5 years, and others in whom the risks of intensive glycemic control appear to outweigh the benefits, a less stringent target such as HbA1c of 8% is appropriate".
The primary issue requiring management is that of the glucose cycle. In this, glucose in the bloodstream is made available to cells in the body; a process dependent upon the twin cycles of glucose entering the bloodstream, and insulin allowing appropriate uptake into the body cells. Both aspects can require management. Another issue that ties along with the glucose cycle is getting a balanced amount of the glucose to the major organs so they are not affected negatively.
The main complexities stem from the nature of the feedback loop of the glucose cycle, which is sought to be regulated:
- The glucose cycle is a system which is affected by two factors: entry of glucose into the bloodstream and also blood levels of insulin to control its transport out of the bloodstream
- As a system, it is sensitive to diet and exercise
- It is affected by the need for user anticipation due to the complicating effects of time delays between any activity and the respective impact on the glucose system
- Management is highly intrusive, and compliance is an issue, since it relies upon user lifestyle change and often upon regular sampling and measuring of blood glucose levels, multiple times a day in many cases
- It changes as people grow and develop
- It is highly individual
As diabetes is a prime risk factor for cardiovascular disease, controlling other risk factors which may give rise to secondary conditions, as well as the diabetes itself, is one of the facets of diabetes management. Checking cholesterol, LDL, HDL and triglyceride levels may indicate hyperlipoproteinemia, which may warrant treatment with hypolipidemic drugs. Checking the blood pressure and keeping it within strict limits (using diet and antihypertensive treatment) protects against the retinal, renal and cardiovascular complications of diabetes. Regular follow-up by a podiatrist or other foot health specialists is encouraged to prevent the development of diabetic foot. Annual eye exams are suggested to monitor for progression of diabetic retinopathy.
Late in the 19th century, sugar in the urine (glycosuria) was associated with diabetes. Various doctors studied the connection. Frederick Madison Allen studied diabetes in 1909–12, then published a large volume, Studies Concerning Glycosuria and Diabetes, (Boston, 1913). He invented a fasting treatment for diabetes called the Allen treatment for diabetes. His diet was an early attempt at managing diabetes.
Blood sugar level is measured by means of a glucose meter, with the result either in mg/dL (milligrams per deciliter in the US) or mmol/L (millimoles per litre in Canada and Eastern Europe) of blood. The average normal person has an average fasting glucose level of 4.5 mmol/L (81 mg/dL), with a lows of down to 2.5 and up to 5.4 mmol/L (65 to 98 mg/dL).
Optimal management of diabetes involves patients measuring and recording their own blood glucose levels. By keeping a diary of their own blood glucose measurements and noting the effect of food and exercise, patients can modify their lifestyle to better control their diabetes. For patients on insulin, patient involvement is important in achieving effective dosing and timing.
Hypo and hyperglycemia
Levels which are significantly above or below this range are problematic and can in some cases be dangerous. A level of <3.8 mmol/L (<70 mg/dL) is usually described as a hypoglycemic attack (low blood sugar). Most diabetics know when they are going to "go hypo" and usually are able to eat some food or drink something sweet to raise levels. A patient who is hyperglycemic (high glucose) can also become temporarily hypoglycemic, under certain conditions (e.g. not eating regularly, or after strenuous exercise, followed by fatigue). Intensive efforts to achieve blood sugar levels close to normal have been shown to triple the risk of the most severe form of hypoglycemia, in which the patient requires assistance from by-standers in order to treat the episode. In the United States, there were annually 48,500 hospitalizations for diabetic hypoglycemia and 13,100 for diabetic hypoglycemia resulting in coma in the period 1989 to 1991, before intensive blood sugar control was as widely recommended as today. One study found that hospital admissions for diabetic hypoglycemia increased by 50% from 1990–1993 to 1997–2000, as strict blood sugar control efforts became more common. Among intensively controlled type 1 diabetics, 55% of episodes of severe hypoglycemia occur during sleep, and 6% of all deaths in diabetics under the age of 40 are from nocturnal hypoglycemia in the so-called 'dead-in-bed syndrome,' while National Institute of Health statistics show that 2% to 4% of all deaths in diabetics are from hypoglycemia. In children and adolescents following intensive blood sugar control, 21% of hypoglycemic episodes occurred without explanation. In addition to the deaths caused by diabetic hypoglycemia, periods of severe low blood sugar can also cause permanent brain damage. Although diabetic nerve disease is usually associated with hyperglycemia, hypoglycemia as well can initiate or worsen neuropathy in diabetics intensively struggling to reduce their hyperglycemia.
Levels greater than 13–15 mmol/L (230–270 mg/dL) are considered high, and should be monitored closely to ensure that they reduce rather than continue to remain high. The patient is advised to seek urgent medical attention as soon as possible if blood sugar levels continue to rise after 2–3 tests. High blood sugar levels are known as hyperglycemia, which is not as easy to detect as hypoglycemia and usually happens over a period of days rather than hours or minutes. If left untreated, this can result in diabetic coma and death.
Prolonged and elevated levels of glucose in the blood, which is left unchecked and untreated, will, over time, result in serious diabetic complications in those susceptible and sometimes even death. There is currently no way of testing for susceptibility to complications. Diabetics are therefore recommended to check their blood sugar levels either daily or every few days. There is also diabetes management software available from blood testing manufacturers which can display results and trends over time. Type 1 diabetics normally check more often, due to insulin therapy.
A history of blood sugar level results is especially useful for the diabetic to present to their doctor or physician in the monitoring and control of the disease. Failure to maintain a strict regimen of testing can accelerate symptoms of the condition, and it is therefore imperative that any diabetic patient strictly monitor their glucose levels regularly.
Glycemic control is a medical term referring to the typical levels of blood sugar (glucose) in a person with diabetes mellitus. Much evidence suggests that many of the long-term complications of diabetes, especially the microvascular complications, result from many years of hyperglycemia (elevated levels of glucose in the blood). Good glycemic control, in the sense of a "target" for treatment, has become an important goal of diabetes care, although recent research suggests that the complications of diabetes may be caused by genetic factors or, in type 1 diabetics, by the continuing effects of the autoimmune disease which first caused the pancreas to lose its insulin-producing ability.
Because blood sugar levels fluctuate throughout the day and glucose records are imperfect indicators of these changes, the percentage of hemoglobin which is glycosylated is used as a proxy measure of long-term glycemic control in research trials and clinical care of people with diabetes. This test, the hemoglobin A1c or glycosylated hemoglobin reflects average glucoses over the preceding 2–3 months. In nondiabetic persons with normal glucose metabolism the glycosylated hemoglobin is usually 4–6% by the most common methods (normal ranges may vary by method).
"Perfect glycemic control" would mean that glucose levels were always normal (70–130 mg/dl, or 3.9–7.2 mmol/L) and indistinguishable from a person without diabetes. In reality, because of the imperfections of treatment measures, even "good glycemic control" describes blood glucose levels that average somewhat higher than normal much of the time. In addition, one survey of type 2 diabetics found that they rated the harm to their quality of life from intensive interventions to control their blood sugar to be just as severe as the harm resulting from intermediate levels of diabetic complications.
In the 1990s the American Diabetes Association conducted a publicity campaign to persuade patients and physicians to strive for average glucose and hemoglobin A1c values below 200 mg/dl (11 mmol/l) and 8%. Currently, many patients and physicians attempt to do better than that.
As of 2015 the guidelines called for an HbA1c of around 7% or a fasting glucose of less than 7.2 mmol/L (130 mg/dL); however these goals may be changed after professional clinical consultation, taking into account particular risks of hypoglycemia and life expectancy. Despite guidelines recommending that intensive blood sugar control be based on balancing immediate harms and long-term benefits, many people – for example people with a life expectancy of less than nine years – who will not benefit are over-treated and do not experience clinically meaningful benefits.
Poor glycemic control refers to persistently elevated blood glucose and glycosylated hemoglobin levels, which may range from 200 to 500 mg/dl (11–28 mmol/L) and 9–15% or higher over months and years before severe complications occur. Meta-analysis of large studies done on the effects of tight vs. conventional, or more relaxed, glycemic control in type 2 diabetics have failed to demonstrate a difference in all-cause cardiovascular death, non-fatal stroke, or limb amputation, but decreased the risk of nonfatal heart attack by 15%. Additionally, tight glucose control decreased the risk of progression of retinopathy and nephropathy, and decreased the incidence peripheral neuropathy, but increased the risk of hypoglycemia 2.4 times.
Relying on their own perceptions of symptoms of hyperglycemia or hypoglycemia is usually unsatisfactory as mild to moderate hyperglycemia causes no obvious symptoms in nearly all patients. Other considerations include the fact that, while food takes several hours to be digested and absorbed, insulin administration can have glucose lowering effects for as little as 2 hours or 24 hours or more (depending on the nature of the insulin preparation used and individual patient reaction). In addition, the onset and duration of the effects of oral hypoglycemic agents vary from type to type and from patient to patient.
Personal (home) glucose monitoring
Control and outcomes of both types 1 and 2 diabetes may be improved by patients using home glucose meters to regularly measure their glucose levels. Glucose monitoring is both expensive (largely due to the cost of the consumable test strips) and requires significant commitment on the part of the patient. Lifestyle adjustments are generally made by the patients themselves following training by a clinician.
Regular blood testing, especially in type 1 diabetics, is helpful to keep adequate control of glucose levels and to reduce the chance of long term side effects of the disease. There are many (at least 20+) different types of blood monitoring devices available on the market today; not every meter suits all patients and it is a specific matter of choice for the patient, in consultation with a physician or other experienced professional, to find a meter that they personally find comfortable to use. The principle of the devices is virtually the same: a small blood sample is collected and measured. In one type of meter, the electrochemical, a small blood sample is produced by the patient using a lancet (a sterile pointed needle). The blood droplet is usually collected at the bottom of a test strip, while the other end is inserted in the glucose meter. This test strip contains various chemicals so that when the blood is applied, a small electrical charge is created between two contacts. This charge will vary depending on the glucose levels within the blood. In older glucose meters, the drop of blood is placed on top of a strip. A chemical reaction occurs and the strip changes color. The meter then measures the color of the strip optically.
Self-testing is clearly important in type I diabetes where the use of insulin therapy risks episodes of hypoglycemia and home-testing allows for adjustment of dosage on each administration. Its benefit in type 2 diabetes has been more controversial, but recent studies have resulted in guidance. that self-monitoring does not improve blood glucose or quality of life.
Benefits of control and reduced hospital admission have been reported. However, patients on oral medication who do not self-adjust their drug dosage will miss many of the benefits of self-testing, and so it is questionable in this group. This is particularly so for patients taking monotherapy with metformin who are not at risk of hypoglycaemia. Regular 6 monthly laboratory testing of HbA1c (glycated haemoglobin) provides some assurance of long-term effective control and allows the adjustment of the patient's routine medication dosages in such cases. High frequency of self-testing in type 2 diabetes has not been shown to be associated with improved control. The argument is made, though, that type 2 patients with poor long term control despite home blood glucose monitoring, either have not had this integrated into their overall management, or are long overdue for tighter control by a switch from oral medication to injected insulin.
Continuous Glucose Monitoring (CGM) CGM technology has been rapidly developing to give people living with diabetes an idea about the speed and direction of their glucose changes. While it still requires calibration from SMBG and is not indicated for use in correction boluses, the accuracy of these monitors is increasing with every innovation. The Libre Blood Sugar Diet Program utilizes the CGM and Libre Sensor and by collecting all the data through a smartphone and smartwatch experts analyze this data 24/7 in Real Time. The results are that certain foods can be identified as causing one's blood sugar levels to rise and other foods as safe foods- that do not make a person's blood sugar levels to rise. Each individual absorbs sugar differently and this is why testing is a necessity.
A useful test that has usually been done in a laboratory is the measurement of blood HbA1c levels. This is the ratio of glycated hemoglobin in relation to the total hemoglobin. Persistent raised plasma glucose levels cause the proportion of these molecules to go up. This is a test that measures the average amount of diabetic control over a period originally thought to be about 3 months (the average red blood cell lifetime), but more recently thought to be more strongly weighted to the most recent 2 to 4 weeks. In the non-diabetic, the HbA1c level ranges from 4.0 to 6.0%; patients with diabetes mellitus who manage to keep their HbA1c level below 6.5% are considered to have good glycemic control. The HbA1c test is not appropriate if there has been changes to diet or treatment within shorter time periods than 6 weeks or there is disturbance of red cell aging (e.g. recent bleeding or hemolytic anemia) or a hemoglobinopathy (e.g. sickle cell disease). In such cases, the alternative Fructosamine test is used to indicate average control in the preceding 2 to 3 weeks.
Continuous glucose monitoring
The first CGM device made available to consumers was the GlucoWatch biographer in 1999. This product is no longer sold. It was a retrospective device rather than live. Several live monitoring devices have subsequently been manufactured which provide ongoing monitoring of glucose levels on an automated basis during the day.
m-health monitoring Applications
The widespread use of smartphones has turned mobile applications (apps) into a popular means of the usage of all forms of software. As a consequence, the use of mobile apps in managing people's health and supporting their chronic conditions is receiving popularity, especially among healthcare systems, which are showing a great tendency toward using these apps to integrate patient-generated data into electronic health records, and to modify and improve treatment plans accordingly. The number of health-related apps accessible in the App Store and Google Play is approximately 100,000, and among these apps, the ones related to diabetes are the highest in number. Conducting regular self-management tasks such as medication and insulin intake, blood sugar checkup, diet observance, and physical exercise are really demanding. This is why the use of diabetes-related apps for the purposes of recording diet and medication intake or blood glucose level is promising to improve the health condition for the patients. However, despite the high number of apps, the rate of their usage among the patients is not high. One of the reasons for this could be due to the design problems that affect their usability. In addition, a 2016 study of 65 diabetes apps for Android revealed that sensitive data, such as insulin and blood glucose levels, "was routinely collected and shared with third parties".
The British National Health Service launched a programme targeting 100,000 people at risk of diabetes to lose weight and take more exercise in 2016. In 2019 it was announced that the programme was successful. The 17,000 people who attended most of the healthy living sessions had, collectively lost nearly 60,000 kg, and the programme was to be doubled in size.
Because high blood sugar caused by poorly controlled diabetes can lead to a plethora of immediate and long-term complications, it is critical to maintain blood sugars as close to normal as possible, and a diet that produces more controllable glycemic variability is an important factor in producing normal blood sugars.
People with type 1 diabetes who use insulin can eat whatever they want, preferably a healthy diet with some carbohydrate content; in the long term it is helpful to eat a consistent amount of carbohydrate to make blood sugar management easier.
There is a lack of evidence of the usefulness of low-carbohydrate dieting for people with . Although for certain individuals it may be feasible to follow a low-carbohydrate regime combined with carefully managed insulin dosing, this is hard to maintain and there are concerns about potential adverse health effects caused by the diet. In general people with type 1 diabetes are advised to follow an individualized eating plan rather than a pre-decided one.
Currently, one goal for diabetics is to avoid or minimize chronic diabetic complications, as well as to avoid acute problems of hyperglycemia or hypoglycemia. Adequate control of diabetes leads to lower risk of complications associated with unmonitored diabetes including kidney failure (requiring dialysis or transplant), blindness, heart disease and limb amputation. The most prevalent form of medication is hypoglycemic treatment through either oral hypoglycemics and/or insulin therapy. There is emerging evidence that full-blown diabetes mellitus type 2 can be evaded in those with only mildly impaired glucose tolerance.
Patients with type 1 diabetes mellitus require direct injection of insulin as their bodies cannot produce enough (or even any) insulin. As of 2010, there is no other clinically available form of insulin administration other than injection for patients with type 1: injection can be done by insulin pump, by jet injector, or any of several forms of hypodermic needle. Non-injective methods of insulin administration have been unattainable as the insulin protein breaks down in the digestive tract. There are several insulin application mechanisms under experimental development as of 2004, including a capsule that passes to the liver and delivers insulin into the bloodstream. There have also been proposed vaccines for type I using glutamic acid decarboxylase (GAD), but these are currently not being tested by the pharmaceutical companies that have sublicensed the patents to them.
For type 2 diabetics, diabetic management consists of a combination of diet, exercise, and weight loss, in any achievable combination depending on the patient. Obesity is very common in type 2 diabetes and contributes greatly to insulin resistance. Weight reduction and exercise improve tissue sensitivity to insulin and allow its proper use by target tissues. Patients who have poor diabetic control after lifestyle modifications are typically placed on oral hypoglycemics. Some Type 2 diabetics eventually fail to respond to these and must proceed to insulin therapy. A study conducted in 2008 found that increasingly complex and costly diabetes treatments are being applied to an increasing population with type 2 diabetes. Data from 1994 to 2007 was analyzed and it was found that the mean number of diabetes medications per treated patient increased from 1.14 in 1994 to 1.63 in 2007.
Patient education and compliance with treatment is very important in managing the disease. Improper use of medications and insulin can be very dangerous causing hypo- or hyper-glycemic episodes.
For type 1 diabetics, there will always be a need for insulin injections throughout their life, as the pancreatic beta cells of a type 1 diabetic are not capable of producing sufficient insulin. However, both type 1 and type 2 diabetics can see dramatic improvements in blood sugars through modifying their diet, and some type 2 diabetics can fully control the disease by dietary modification.
Insulin therapy requires close monitoring and a great deal of patient education, as improper administration is quite dangerous. For example, when food intake is reduced, less insulin is required. A previously satisfactory dosing may be too much if less food is consumed causing a hypoglycemic reaction if not intelligently adjusted. Exercise decreases insulin requirements as exercise increases glucose uptake by body cells whose glucose uptake is controlled by insulin, and vice versa. In addition, there are several types of insulin with varying times of onset and duration of action.
Several companies are currently working to develop a non-invasive version of insulin, so that injections can be avoided. Mannkind has developed an inhalable version, while companies like Novo Nordisk, Oramed and BioLingus have efforts undergoing for an oral product. Also oral combination products of insulin and a GLP-1 agonist are being developed.
Insulin therapy creates risk because of the inability to continuously know a person's blood glucose level and adjust insulin infusion appropriately. New advances in technology have overcome much of this problem. Small, portable insulin infusion pumps are available from several manufacturers. They allow a continuous infusion of small amounts of insulin to be delivered through the skin around the clock, plus the ability to give bolus doses when a person eats or has elevated blood glucose levels. This is very similar to how the pancreas works, but these pumps lack a continuous "feed-back" mechanism. Thus, the user is still at risk of giving too much or too little insulin unless blood glucose measurements are made.
A further danger of insulin treatment is that while diabetic microangiopathy is usually explained as the result of hyperglycemia, studies in rats indicate that the higher than normal level of insulin diabetics inject to control their hyperglycemia may itself promote small blood vessel disease. While there is no clear evidence that controlling hyperglycemia reduces diabetic macrovascular and cardiovascular disease, there are indications that intensive efforts to normalize blood glucose levels may worsen cardiovascular and cause diabetic mortality.