INSULIN THERAPY IN MANAGING DIABETES
What is the role of Insulin in the body? What is the importance of Insulin?
Insulin is an anabolic hormone secreted by beta cells granules located in a gland called pancreas in human body. It regulates glucose metabolism and promotes growth of body tissues. Insulin is secreted throughout 24 hours a day at basal rate to meet the metabolic demands of the body and its secretion is augmented in response to meal to address the extra metabolic demand created by food consumption. Unfortunately, in subjects prone to develop diabetes, there is progressive decline in beta cell function leading to absolute or relative deficiency of insulin over a period of time, necessitating provision of exogenous insulin for glucose handling, & tissue survival. Deficiency of insulin prevents utilisation of food by different tissues of the body, particularly muscles, fat cells, liver etc. This prevents conversion of fuels into meaningful energy required to meet daily activities of human body. As a natural corollary, insulin is of vital importance for survival of human body.
Does every diabetes patient needs insulin therapy?
Diabetes is a heterogeneous disorder and insulin requirement varies depending upon the type of diabetes, presence of co - morbidities and situations where body requires extra amount of insulin to meet the energy requirements created by stressful situations. Type 1 Diabetes, which usually starts in children and young adolescents is characterised by auto immune destruction of pancreas leading to absolute deficiency of insulin. Obviously these subjects require insulin for survival and therefore insulin administration is a must and of paramount importance in these individuals. Individuals with Type 2 Diabetes which afflicts more than 95% of our population is characterised by relative insulin deficiency and very importantly by persistent “insulin resistance”. This would explain that these subjects can be managed by life style measures including prudent diet, regular exercise along with various oral anti diabetic drugs for a considerable length of time. However, the innate nature of the disease characterised by inexorable progression leads to requirement of insulin after few years of diagnosis. Beyond the genetic predilection this requirement of insulin depends upon the quality of glucose control by such individuals. Those with poor control will need insulin sooner as compared with those who keep their sugar under strict control by measures mentioned earlier. Furthermore, Type 2 Diabetic subjects will require insulin in situations of stress like pregnancy, during major operations, in presence of severe concomitant infections and complications involving liver, kidney and heart etc. Insulin is also required in newly diagnosed Type 2 Diabetics if they present with very high blood sugar levels along with florid symptoms like excessive urination and thirst with or without significant weight loss. These subjects require insulin for a very short period of 2 to 6 weeks only and subsequently can be managed by oral drugs and life style measures for a considerable length of time.
Which are the different types of insulin therapy available for treatment of diabetes? Are there any differences amongst them?
Insulin is available in two different forms, basal and prandial. The very name suggests that basal insulin meets the 24 hours basal requirement of insulin. On the other hand prandial insulins are required to cover the meal related surges in blood sugar levels. It is also possible to combine basal and prandial insulins in to one insulin formulation and they are called pre mixed insulin or insulin co - formulations. There are seminal differences in the properties of all commercially available insulins. They differ in the rapidity of the onset of action, total duration of action, propensity to cause hypoglycemia (low blood sugar), and smoothness of control (glycemic variability) and with respect to frequency of administration. Basal insulins are generally given once daily because newer basal insulin analogues are effective for 24 hours a day. On the other hand prandial insulins have to be given 1-3 times daily depending upon the largest glucose excursion whether that is happening post breakfast, post lunch or post dinner. They can also be given along with largest meals of the day. Pre mixed insulins or C - formulations have the advantage of fewer insulin injections required over 24 hours, coverage of both fasting and post meal blood sugar levels and being convenient in daily administration using single insulin pen to meet both basal and post meal requirements. It is incumbent upon the physician to select appropriate insulin for the subject depending upon the blood sugar profiles, motivation of the subject, cost considerations, ability to monitor glucose at home and family support. “One size doesn’t fit all”.
How should insulin be taken?
Most of the modern insulins need to be taken just before meal or along with meals. Insulins are available in vials which are very cheap and can be administered by insulin syringes. However, availability of insulin pens and pre filled cartridges have completely revolutionised insulin administration, as they are convenient, almost painless and can be used anywhere without the need for mixing. It is important to take meal following insulin administration to avoid hypoglycemia. Modern insulins like Degludec and a combination of Degludec and Aspart provide unique flexibility that they can be administered at any time of the day if the subject forgets to take at the prescribed time of the day. Insulin is best administered beneath the skin of abdominal wall about an inch away from the umbilicus. The injection site should be rotated in a circular fashion. However, it can also be taken over front of thighs, over forearms, buttocks etc.
What precautions one should take while on insulin therapy?
Manufacturers of insulin and retailers dispensing the insulin need to maintain the cold chain required to preserve the potency of the drug. The subjects can store insulin in the refrigerator (not in the freezer compartment) or in any cold corner of the house. They should ensure that they take meal following insulin injection (within 5 minutes after modern insulins) and (in about 30 minutes after conventional insulins). Children with Type 1 Diabetes need to adjust doses of insulin depending upon the severity of exercise and nature of games in close collaboration with the physician, family members and school authorities. Proper dose selection in visually impaired subjects is also of paramount importance to prevent less or excess doses. Proper mixing is necessary for those conventional insulins which require re - suspension.
What are the most commonly encountered myths about insulin treatment?
Insulin has always been a subject of myths and controversies, nevertheless the fact that this is the most effective agent to control diabetes and is unavoidable in majority of the case. In fact it is a lifesaving drug.
Commonest myths surrounding insulin treatment include:
Once on insulin, always on insulin Insulin causes damage to kidneys and liver Insulin is the last resort Insulin should be avoided as far as possible It is the responsibility of the medical fraternity, government and media to create awareness regarding insulin treatment. Not all subjects require insulin and “once on insulin always on insulin” is completely wrong. Insulin doesn’t cause any damage to kidneys and liver. It is the uncontrolled disease which is responsible for damage to kidneys, eyes, heart etc. Insulin is not the last resort and in fact given at appropriate stage in the natural history of the disease, has the potential to prevent majority of long term complications of diabetes and keep the diabetic subjects in best of health and full of energy.