Nov 01, 2014
Are You Prepared for the Storm?
Type 2 diabetes: Fundamentals of treatment
Due to factors such as demographic shift and increasing levels of obesity, the prevalence of diabetes worldwide is rising to epidemic proportions. Indeed, diabetes is one of the fastest growing diseases in Canada. The Public Health Agency of Canada (2011) reports a 70 per cent increase in prevalence between 1998 and 2009 and that by 2019, as many as 3.7 million Canadians will have been diagnosed. Nine out of 10 of these diagnoses will be for type 2 diabetes (T2D). More and more nurses will be treating patients with this disease. With individualized treatment regimens becoming increasingly complex, the role of nurses in education and disease management is crucial.
Every five years, the Canadian Diabetes Association (CDA) updates its clinical practice guidelines. I was one of the 120 professionals who volunteered to review and assess all relevant evidence for the 2013 revision of the guidelines and creation of a website for health-care professionals. I have been a member of the steering and executive committees for this initiative since 2005 and have contributed as a chapter author. Over the 25 years I have worked in this area, I have witnessed an explosion of research activities and new treatment options. By sharing some of the updates to the guidelines and findings from the latest research, I hope to support RN practice in this area and reinforce the role we play in the management and treatment of this disease.
More aggressive treatment needed
The 2013 clinical practice guidelines highlight the importance of using the chronic care model in a comprehensive approach to T2D management, which includes self-management education and support, team-based care, monitoring and case management. The guidelines incorporate updates based on research published since 2008, including revised diagnostic and treatment recommendations and new patient care flow sheets. As well, several new topics are covered, such as complementary and alternative therapies and in-hospital management.
One of the overall messages in the 2013 guidelines is that treatment needs to be more aggressive in lowering blood glucose because many patients are not reaching recommended targets. For example, results of the DM-SCAN, which collected data on 5,123 Canadian patients with T2D, specifically whether they achieved A1C, LDL and blood pressure targets established by CDA, showed that only 50 per cent of the patients achieved A1C <7% and 13 per cent met all three targets (Leiter et al., 2013). Ideally, individualized glucose targets should be achieved within three to six months of diagnosis. If the patient is not reaching goals with lifestyle intervention alone within two to three months, pharmacological therapy is added, beginning with an oral antihyperglycemic agent. With a higher initial blood glucose level, a second antihyperglycemic agent, such as insulin, should be considered.
Unfortunately, there is clinical inertia in establishing insulin therapy in T2D patients, even when their labs show evidence of chronic, poorly controlled hyperglycemia. In a Canadian study, insulin therapy was initiated on average 9.2 years after diagnosis, when mean A1C was 9.5%, and 75 per cent of patients had already experienced complications of diabetes (Harris, Kapor, Lank, Willan, & Houston, 2010). Among the reasons patients are reluctant to begin insulin treatment are fear of hypoglycemia and weight gain (Ross, Tildesley, & Ashkenas, 2011), both of which can be managed using slow, steady titration of insulin doses and lifestyle counselling (Harris, Yale, Dempsey, & Gerstein, 2008). Nurses are in a position to counsel patients on these issues, to help ensure proper monitoring of glucose levels and to help identify those who might benefit from the initiation of insulin therapy.
Hypoglycemia is defined as a glucose <4.0 mmol/L in patients treated with injectable insulin or with medication that increases insulin production (known as insulin secretagogues). Symptoms include sweating, shaking, dizziness, headache, blurred vision, fatigue, hunger, pallor, palpitations, nausea and tingling. In rare instances, severe hypoglycemia may lead to coma or even death. Nocturnal hypoglycemia can present differently, with symptoms such as restless sleep, night sweats, and waking with a headache, and is particularly concerning because of the risk that the patient may be unaware of the event and unable to remedy the problem (Yale, 2004). If there is evidence of nocturnal hypoglycemia, the benefits and risk of a basal insulin analogue, which are associated with reduced rates of hypoglycemia (Hermansen et al., 2006), should be discussed.
Nurses should be ready to discuss the prevention, identification and treatment of hypoglycemia with patients and their families. Previously thought of as uncommon in T2D, hypoglycemia has been found to occur frequently and is often undetected (Filteau et al., 2014; Woo, Brod, Barnett, Peyrot, & Leiter, 2012). We now have a greater awareness of its impact on quality of life and on adherence to treatment plans. In managing T2D, a goal of treatment now includes achieving the composite endpoint of target A1C while avoiding weight gain and hypoglycemia (Zinman, Schmidt, Moses, Lund, & Gough, 2012).
Monitoring blood glucose
Insulin doses are initiated and adjusted (a process known as titration) so the patient can achieve and maintain effective control of blood glucose while avoiding hypoglycemia. Blood glucose monitoring is typically carried out by self-monitoring, but nurses may monitor glucose for patients in an institutional setting. The recommended frequency of monitoring depends on several factors, including insulin regimen. Patients who use only a single daily injection with a basal insulin should monitor at least once daily. Patients taking two or more insulin injections daily should monitor at least three times per day, including tests of pre-and post-meal glucose levels. The A1C blood test indicates average blood glucose over the previous three to four months. This blood test should be done at least every six months, and every three months if the patient is not at target or the treatment is being adjusted.
Intensification of treatment
For patients who are not able to achieve glucose control using oral antihyperglycemic agents alone, the CDA guidelines advocate the initiation of basal insulin in addition to oral agents as the next step in diabetes management. The “10+1 approach” is often used, in which the patient begins with a single daily dose of 10 units of basal insulin, then monitors their blood glucose after at least eight hours of fasting. The patient adds one unit of basal insulin to their daily injection every day until their fasting blood glucose (FBG) has reached the target that was set, and continues monitoring their FBG each day. The insulin dose may be reduced by one or two units if FBG remains consistently at the low end of the desired range or if hypoglycemia has occurred. Insulin may also be introduced: premixed basal and bolus (once or twice daily) or basal bolus, a regimen of basal at bedtime and rapid acting at each meal.
Diabetes is a progressive disease. Even patients experiencing good control of their blood glucose for an extended period may require new treatments added to their regimen. One simple approach to intensification is basal-plus insulin therapy, in which a patient on a stable basal insulin regimen adds a single mealtime bolus injection, which may be taken at breakfast, lunch or dinner, depending on which meal causes the greatest rise in blood glucose (Owens, 2013). A recent Canadian study demonstrated that starting bolus at breakfast could be easily and effectively done in primary care with the patient self-titrating the dose (Harris et al., 2014). While self-administration of insulin is the norm for most patients outside the institutional setting, many inpatients depend on nurses to provide insulin injections. It is therefore critical for nurses to understand the time action profiles of insulin as well as the mechanics of insulin injection and the proper and safe use of injection devices.
Insulin can be delivered by syringe and vial, insulin pens or continuous subcutaneous insulin infusion pumps (CSII). Two types of pens are available: durable, meaning a new insulin cartridge is inserted for each injection, and prefilled, meaning the entire unit is disposable. Insulin pens are used by about 60 per cent of insulin users worldwide, although usage varies greatly depending on geography and on the circumstances of the initial prescription and patient training (Perfetti, 2010). Patients often prefer pens as this form of delivery is more reliable and more discreet than syringe-and-vial delivery (Bailey, Thurman, Niemeyer, & Schmeisl, 2011).
Pens have numerous advantages over standard syringes. They deliver a highly reproducible insulin dose, which the user selects by dialing in the dose — safer than drawing back an insulin syringe, especially for individuals with limited dexterity or eyesight. In fact, health-care providers and patients prefer insulin pens to syringes and vials (Pfützner et al., 2013). The devices are designed to be used with insulin from a single supplier, but different formulations are available, including basal, bolus and premixed.
From the nurse’s point of view, both prefilled and durable pens are good options. Patients may find the colour-coding of prefilled pens helpful, particularly if they have different kinds of insulin that they must use at different times and titrate individually. Using a syringe injection may be appropriate for some T2D patients, such as those requiring insulin doses of higher volume than an insulin pen can deliver (>80 units per dose). Also, in many institutions, insulin pens are not available unless patients are permitted to use their own. For now, in the hospital setting, syringes and vials continue to be the norm.
The maximum dose an insulin syringe can deliver is 100 units. When a patient requires a dose that is higher than the device or syringe can deliver, the dose should be split and given in two separate injections, using new needles and two different sites. For intermediate-acting (NPH) and short-acting (regular) human insulin, the dose may be split to improve the time action profile, which becomes blunted with increased volume of injection.
With insulin analogues, there is no evidence that splitting the dose improves the time action profile. When a patient requires a dose that is higher, two injections should be given 12 hours apart. A flatter, longer basal insulin profile will result.
Use of CSII is increasing, primarily in patients with type 1 diabetes. These devices provides basal insulin at rates that are pre-set along with bolus doses, which are calculated based on current glucose levels, food intake and activity level.
For best practices in insulin delivery, a resource I direct providers to is the Forum for Injection Technique Canada website.
Diabetes care for frail elderly patients
Diabetes care for physically fit and mentally acute older patients with T2D is generally similar to that for other adults. For frail elderly patients, however, the short- and long-term benefits of tight glycemic control are not clear. To avoid hypoglycemia, a more appropriate A1C target may be ≤8.5% because older patients have difficulty detecting hypoglycemia (Tkacs, 2002).
For older adults, insulin regimens must be kept simple, and individuals with cognitive difficulties may require assistance in determining their appropriate dose. Insulin analogues are preferred, to reduce the risk of hypoglycemia. In the interest of simplicity, premixed insulin is often used to avoid the need to titrate basal and bolus insulins separately. To prevent dosing errors, it is important to establish and monitor cognitive function when a frail elderly person is using insulin. If the individual has low body weight, a 4-mm needle and a skin lift may be necessary to avoid intramuscular injection
Traditional medications for T2D have been associated with hypoglycemia and weight gain. The addition of two new classes of medications - incretin agents and SGLT2 inhibitors — have provided a different approach to achieving glucose targets.
Incretins, specifically the hormone glucagon-like peptide-1 (GLP-1), play a role in glucose control by increasing insulin production and decreasing glucagon. GLP-1 levels are low in people with T2D and are broken down quickly by the enzyme dipeptidyl peptidase-4 (DPP-4). If we allow GLP-1 to work longer, using a DPP-4 inhibitor oral agent, or raise GLP-1 levels with GLP-1 receptor agonist injections, we can improve glucose control. These agents cause a reduction in blood glucose that is comparable to that of other agents (Goldenberg, 2013) and are associated with a lower risk of hypoglycemia. DPP-4 is weight neutral and GLP-1RAs promote weight loss.
Sodium-glucose co-transporter 2 (SGLT2) inhibitors are oral agents that excrete approximately 70-120 grams of glucose per day in the urine, which results in improvement in A1C levels. The most important thing about these additions to the tool box is that there is significantly less risk of hypoglycemia and weight gain.
Irrespective of the advances made in pharmacological management, it is education and support that are the cornerstones of diabetes management. An underlying problem for the majority of people living with T2D is lack of regular access to the education and support they need to self-manage their illness. My hope is that more nurses will come to understand this disease and its treatment and be able to help patients self-manage successfully.
Bailey, T., Thurman, J., Niemeyer, M., & Schmeisl, G. (2011). Usability and preference evaluation of a prefilled insulin pen with a novel injection mechanism by people with diabetes and healthcare professionals. Current Medical Research and Opinion, 27(10), 2043-2052.
Filteau, P., Lavernia, F., Tomky, D. M., Mcghee, T. A., Dex, T., Dalal, M.,…Vlajnic, A. (2014). Significance of hypoglycemia in type 2 diabetes mellitus patients in primary care. Canadian Journal of Diabetes, 38(5), S47-S48.
Goldenberg, R. (2013). Insulin plus incretin agent combination therapy in type 2 diabetes: A systematic review. Current Medical Research and Opinion, 30(3), 431-445.
Harris, S. B., Kapor, J., Lank, C. N., Willan, A. R., & Houston, T. (2010). Clinical inertia in patients with T2DM requiring insulin in family practice. Canadian Family Physician, 56(12), e418-e424.
Harris, S. B., Yale, J.-F., Berard, L., Stewart, J., Abbaszadeh, B., Webster-Bogaert, S., & Gerstein, H. C. (2014). Does a patient-managed insulin intensification strategy with insulin glargine and insulin glulisine provide similar glycemic control as a physician-managed strategy? Results of the START (Self-Titration With Apidra to Reach Target) Study. Diabetes Care, 37(3), 604-610.
Harris, S. B., Yale, J.-F., Dempsey, E., & Gerstein, H. (2008). Can family physicians help patients initiate basal insulin therapy successfully? Randomized trial of patient-titrated insulin glargine compared with standard oral therapy: Lessons for family practice from the Canadian INSIGHT trial. Canadian Family Physician, 54(4), 550-558.
Hermansen, K., Davies, M., Derezinski, T., Martinez Ravn, G., Clauson, P., & Home, P. (2006). A 26-week, randomized, parallel, treat-to-target trial comparing insulin detemir with NPH insulin as add-on therapy to oral glucose-lowering drugs in insulin-naïve people with type 2 diabetes. Diabetes Care, 29(6), 1269-1274.
Leiter, L. A., Berard, L., Bowering, C. K., Cheng, A. Y., Dawson, K. G., Ekoé, J. M.,…Langer, A. (2013). Type 2 diabetes mellitus management in Canada: Is it improving? Canadian Journal of Diabetes, 37(2), 82-89.
Owens, D. R. (2013). Stepwise intensification of insulin therapy in type 2 diabetes management — exploring the concept of the basal-plus approach in clinical practice. Diabetic Medicine, 30(3), 276-288.
Perfetti, R. (2010). Reusable and disposable insulin pens for the treatment of diabetes: Understanding the global differences in user preference and an evaluation of inpatient insulin pen use. Diabetes Technology & Therapeutics, 12(Suppl 1), S79-S85.
Pfützner, A., Bailey, T., Campos, C., Kahn, D., Ambers, E., Niemeyer, M.,…Nayberg, I. (2013). Accuracy and preference assessment of prefilled insulin pen versus vial and syringe with diabetes patients, caregivers, and healthcare professionals. Current Medical Research and Opinion, 29(5), 475-481.
Public Health Agency of Canada. (2011). Diabetes in Canada: Facts and figures from a public health perspective. Retrieved from http://www.phac-aspc.gc.ca/cd-mc/publications/diabetes-diabete/facts-figures-faits-chiffres-2011/
Ross, S. A., Tildesley, H. D., & Ashkenas, J. (2011). Barriers to effective insulin treatment: The persistence of poor glycemic control in type 2 diabetes. Current Medical Research and Opinion, 27(Suppl 3), 13-20.
Tkacs, N. C. (2002). Hypoglycemia unawareness. American Journal of Nursing, 102(2), 34-40.
Woo, V. C., Brod, M., Barnett, A. H., Peyrot, M., & Leiter, L. A. (2012). GAPP2™: One in four type 2 diabetes patients in Canada using insulin analogues had irregularities in their basal insulin dosing in the preceding 30 days. Canadian Journal of Diabetes, 36(5), Suppl, S40.
Yale, J.-F. (2004). Nocturnal hypoglycemia in patients with insulin-treated diabetes. Diabetes Research & Clinical Practice, 65(Suppl 1), S41-S46.
Zinman, B., Schmidt, W. E., Moses, A., Lund, N., & Gough, S. (2012). Achieving a clinically relevant composite outcome of an HbA1c of < 7% without weight gain or hypoglycaemia in type 2 diabetes: A meta-analysis of the liraglutide clinical trial programme. Diabetes, Obesity and Metabolism, 14(1), 77-82.