Diabetes management requires precise self-care
Diabetes is a group of chronic metabolic disorders characterised by either inherited or acquired deficiencies in insulin function, which results in hyperglycaemia, or excess of glucose (or sugar) in the blood stream, and if untreated or poorly controlled, is associated with long-term tissue and organ damage, primarily of the eyes, kidneys, nerves, heart and blood vessels. Blood glucose (or blood sugar) homeostasis is dependent upon stability between glucose production by the liver and glucose utilisation by tissues throughout the body. This equilibrium is highly regulated by insulin and glucagon, which are two hormones secreted by the endocrine pancreas, via a negative feedback mechanism. Glucose metabolism hinges on the body’s ability to secrete insulin both continuously and in response to increased blood sugar, the ability of insulin to inhibit gluconeogenesis and stimulate glucose disposal, and the ability of glucose to be taken up by peripheral tissue for cellular energy.
There are a number of pathophysiological mechanisms that lead to deficient insulin function resulting in hyperglycaemia including inadequate insulin secretion, reduced tissue responses or a combination of these. Majority of cases fall into two broad etiopathogenetic categories: type 1 and type 2. T1D, which constitutes only 5–10% of those diagnosed with the disease, is an organ-specific cellular mediated autoimmune disorder caused by autoimmune response against pancreatic β-cells and causes absolute insulin secretion deficiency, while T2D, which is significantly more prevalent comprising approximately 90–95% of those diagnosed, is characterised by insulin secretory defects related to inflammation and metabolic stress or insulin resistance, which occurs when cells throughout the body are unable to respond to or take up glucose. Most patients with T2D are obese (BMI≥25kg/m2) or may have an increased body fat percentage, which causes insulin resistance to some degree. Beyond these two classifications, diabetes may also be caused by injury to the pancreas, drugs or chemicals that impair insulin secretion by destroying β-cells, genetic syndromes and infections. In addition, gestational diabetes, or diabetes that develops during pregnancy, refers to any degree of glucose intolerance with onset or first recognition during pregnancy. Because diabetes may develop as a result a variety of mechanisms, symptoms of hyperglycaemia and complications associated with disease are wide ranging and often change over time depending on fundamental disease progression.
Hyperglycaemia is characteristically associated with frequent urination, excessive thirst and hunger, weight loss and blurred vision. Long-term complications associated with mal-managed hyperglycaemia typically include retinopathy, or damage to the blood vessels of the retina, and potentially vision loss and decreased kidney function (nephropathy), which can cause renal failure. Diabetes is also associated with peripheral neuropathy which causes foot ulcers, Charcot foot (or inflammation of the bones, joints and soft tissues of the foot and ankle) and potentially lower extremity amputation. Similarly, diabetic neuropathy of the autonomic nervous system affects cardiovascular, gastrointestinal and genitourinary organ systems. Studies suggest that 65% of all deaths in people with diabetes are related to cardiovascular disease. Accordingly, disease diagnosis and subsequent glycaemic control are essential to the management of acute symptoms and the prevention, postponement or reduction in severity of chronic microvascular and macrovascular complications that significantly contribute to morbidity and mortality.
Aside from primary diagnosis (Exhibit 6), etiopathogenetic classification and degree of hyperglycaemia, which reflects the severity of the metabolic abnormality, together determine treatment. In some individuals with mild insulin resistance, the mainstay of non-pharmacological treatment includes diet, weight reduction and physical activity. If lifestyle intervention is inadequate, glycaemic control may be managed further with the addition of oral glucose lowering therapy. Metformin, which is the preferred initial oral therapy, is a biguanide anti-hyperglycaemic agent that decreases hepatic glucose production, decreases intestinal absorption of glucose and improves insulin sensitivity by increasing peripheral glucose uptake and utilization. However, if metformin monotherapy does not accomplish glycaemic control, then combination therapy using a second or third oral agent typically follows and can be compounded by either weekly or daily non-insulin injections (Exhibit 7).
Exhibit 6: Standards for diabetes diagnosis and normal range values
Diagnostic threshold for diabetes |
Normal range (non-diabetic) |
Notes |
FPG≥ 126 mg/dL |
70 mg/dL ≤ FPG ≥ 100mg/dL |
Fasting defined as no caloric intake for at least eight hours |
2-hr PG≥ 200 mg/dL during 75mg OGTT |
2-hr PG ≤ 140mg/dL |
N/A |
HbA1c≥ 6.5% |
HbA1c≤6.0% |
Certified by NGSP and standardized to DCCT reference assay |
PG≥ 200 mg/dL + characteristic symptoms of hyperglycaemia |
N/A |
N/A |
Source: American Diabetes Association, 2018 standards. Notes: These values exclude diagnostic criteria for gestational diabetes. FPG, fasting plasma glucose; PG, plasma glucose; OGTT, oral glucose tolerance test; HbA1c, haemoglobin A1C, which is a proxy for the average blood glucose levels; DCCT, Diabetes Control and Complications Trial.
Exhibit 7: Select pharmacologic agents for the treatment of diabetes
Drug |
Class |
Company |
Total WW sales 2017 ($m) |
Oral |
|
|
|
Glucophage (metformin hydrochloride) |
biguanide |
Merck, BMS, Sumitomo Dainippon |
909 |
Glumetza (metformin hydrochloride) |
biguanide |
Bausch Health |
172 |
Jardiance (empaglilozin) |
SGLT2i |
Boehringer Ingelheim |
1,139 |
Farxiga (dapagliflozin) |
SGLT2i |
AstraZeneca |
1,021 |
Tradjenta (linagliptin) |
DPP-4i |
Boehringer Ingelheim, Eli Lilly |
1,506 |
Glyxambi (empaglilozin, linagliptin) |
SGLT2i/ DPP-4i |
Boehringer Ingelheim, Eli Lilly |
203 |
Injectable |
|
|
|
Trulicity (dulaglutide) |
GLP-1 RA |
Eli Lilly |
2,030 |
Victoza (liraglutide) |
GLP-1 RA |
Novo Nordisk |
3,521 |
Lantus (insulin glargine) |
Insulin analogue |
Sanofi |
5,223 |
Toujeo (insulin glargine) |
Insulin analogue |
Sanofi |
922 |
Basaglar (insulin glargine) |
Insulin analogue |
Eli Lilly |
432 |
Source: EvaluatePharma and Edison Investment Research. Notes: WW, world-wide; BMS, Bristol-Myers Squibb; GLP-1 RA, glucagon-like peptide receptor agonist; SGLT2i, sodium-glucose co-transporter 2 inhibitor; DPP-4i, dipeptidyl peptidase-4 inhibitor.
Given the multivariable and progressive nature of the disease, the effectiveness of oral anti-hyperglycaemic therapy diminishes and according to the World Health Organization (WHO), approximately 40% of all diabetes patients ultimately depend on insulin injections to maintain glycaemic control. Due to the well understood and predictable nature of risks of this population, the American Diabetes Association recommends that patients measure their blood glucose three or more times per day, although physicians typically prescribe individual recommendations.
SMBG meters, compliance and economic burden
SMBG is important to the safety and efficacy of sustaining glycaemic control such that meter readings achieved via capillary fingertip blood samples determine insulin dosing decisions. Although structured SMBG helps to improve glycaemic control as demonstrated by the lowering of HbA1c levels, patient views of treatment burden are heavily correlated with adherence to self-care. In a review, the self-management of diabetes was found to be physically, intellectually, emotionally and socially challenging. Patients commonly report that SMBG and insulin regimens are burdensome and negatively impact quality of life. Accordingly, reported incidence of poor medication adherence in patients with diabetes, specifically T2D, ranges from 38% to 93%. Poor self-management contributes to increased costs of healthcare resources such as outpatient care, emergency room visits and hospitalisation as well as increased mortality rates. In addition to low patient adherence to self-care recommendations, poor glycaemic control is also attributed to lack of integrated care in health systems and clinical inertia amongst healthcare providers.
In the US, the total estimated cost of diagnosed diabetes in 2017 was $327bn, whereas the most significant medical conditions contributing to the overall cost include ischemic heart disease, myocardial infarction, heart failure, hypertension, conduction disorders and cardiac dysrhythmias, cellulitis occlusion or cerebral arties, end-stage renal disease and renal failure. Moreover, approximately $90bn of those costs were indirectly associated with the disease and primarily attributed to missed days of work (3.7%), reduced work productivity (29.7%), reduced work force participation due to disability (41.7%), household productivity losses for those not in the workforce (2.3%) and premature death (22.1%).13 Also in 2017, an estimated 277,000 deaths were attributable to diabetes, while 85,000 of those list diabetes as the primary cause contributing $8.5bn of lost productivity. In addition, 54%, 28% and 16% of total deaths in the US where renal disease (72,000 deaths), cerebrovascular disease (150,000 deaths) and cardiovascular disease (689,000 deaths) were listed as the primary cause were also attributable to diabetes, respectively. The economic burden of diabetes management is echoed worldwide.