|
|
|
|
![]() |
|
|
Initiating treatment for newly diagnosed diabetes
Fred J. Friel, MPAS, PA-CMr. Friel practices family medicine and urgent care in Boise, Idaho, is a doctoral candidate in health sciences at Touro University International, and also serves as Medical Company Commander in the Idaho Army National Guard.Achieving and maintaining good glycemic control are the cornerstones of treatment for type 2 diabetes. Your role is to provide the patient with the necessary tools and understanding.
Type 2 diabetes is diagnosed when plasma glucose levels are elevated when tested on two subsequent days.1 Normoglycemia is defined as a plasma glucose level of less than 110 mg/dL from a fasting sample, or less than 140 mg/dL on a 2-hour postload glucose (2-h PG) challenge with 75 g of anhydrous glucose. Diabetes is present when the fasting plasma glucose (FPG) level is 126 mg/dL or greater, or the 2-h PG level is greater than 200 mg/dL, 2 days in a row. A patient who has polyuria, polyphagia, unexplained weight loss, or blurred vision and who has a random plasma glucose level greater than 200 mg/dL can also receive the diagnosis, although the glucose elevation should be confirmed on a subsequent day. Impaired fasting glucose (IFG; FPG level, 110-125 mg/dL) and impaired glucose tolerance (IGT; 2-h PG level, 140-200 mg/dL) have been attributed to insulin resistance. Patients who have IFG or IGT will need to be followed closely because both conditions are significant risk factors for developing type 2 diabetes.1,2 The medical history, physical exam, and lab studies for a patient with newly diagnosed type 2 diabetes or one who is beginning care with a new provider should focus on the known complications of persistent hyperglycemia. The medical history includes a review of any symptoms and results of any laboratory tests, including glycosylated hemoglobin A1C levels. Discuss the patient's eating habits, nutritional status, and weight and exercise histories, and ask what other medications are being used to determine whether any of them may affect blood glucose levels. If the patient is currently being treated or has undergone previous treatment for diabetes, discuss which drugs or diets were tried and how the patient used self-monitored blood glucose (SMBG) levels. Ask about the frequency, severity, and cause of any episodes of ketoacidosis and hypoglycemia; past or present infections, particularly skin, foot, dental, and genitourinary (GU) infections; and whether the patient has had any symptoms or received treatment for chronic eye, kidney, nerve, GU, or GI problems or for heart, peripheral vascular, foot, or cerebrovascular complications. Question the patient about risk factors for atherosclerosis, such as smoking, hypertension, obesity, dyslipidemia, and family history. Ask for a sexual and reproductive history, and inquire about use of contraception. In addition, the history should elicit information on lifestyle, cultural, psycho-social, educational, and economic factors that might influence the management of diabetes, and whether the patient uses tobacco, alcohol, or illicit drugs. During the physical examination, measure height, weight, and BP, and perform funduscopic and oral examinations. Palpate the thyroid gland, and listen to the heart. Perform an abdominal exam, looking closely for signs of hepatomegaly. Auscultate and palpate the pulses, and examine the hands, fingers, feet, and skin for signs of acanthosis nigricans. Perform a neurologic examination, and look for signs of conditions that can cause secondary diabetes, such as hemochromatosis or pancreatic disease. The laboratory investigation should include A1C, serum creatinine, and thyrotropin levels (if indicated clinically) and a fasting lipid profile (including total cholesterol, LDL and HDL cholesterol, and triglyceride levels). Test for microalbuminuria, and order an ECG and urinalysis for ketones, protein, and sediment. Consider referrals as indicated (eg, to an ophthalmologist or a podiatrist).3 Understanding glycemic goalsIntensive glycemic control is the key to minimizing the occurrence of microvascular complications of diabetes and, as epidemiologic data suggest, of macrovascular complications as well. The United Kingdom Prospective Diabetic Study (UKPDS) found a diminished incidence of retinopathy, nephropathy, and neuropathy with diminished A1C concentration achieved with tight glycemic control. Intensive therapy frequently requires a complex treatment regimen that includes drugs, diet, exercise, and SMBG measurements several times a day, with a goal of achieving near-normal levels of blood glucose and an A1C value of 7% or lower (see Table 1).
More aggressive goals set by the American College of Endocrinologists (ACE) include an A1C value of 6.5% or lower, preprandial glucose levels of 110 mg/dL or lower, and postprandial glucose levels of 140 mg/dL or lower.4 The ACE recommendations reflect the Diabetes Control and Complications Trial and UKPDS findings that intensive therapy results in less disease burden. Conventional therapy has resulted in higher A1C levels, around 7.9%, in the UKPDS. The UKPDS and the American Diabetes Association (ADA) attribute diabetic complications to higher than normal glycemic levels, and studies have found reduced complications with a lower A1C concentration. A full percentage point reduction of A1Cfor example, 8% to 7%results in 35% fewer microvascular complications, 25% fewer diabetes-related deaths, 18% fewer myocardial infarctions (MIs), and a 7% reduction in all-cause mortality.5 Although patients with type 2 diabetes are particularly at risk for macrovascular disorders, including heart disease, stroke, and cardiovascular disease (CVD), the effect of tight glycemic control on these diseases is unclear.6 One consequence of intensive glycemic control is an increased risk of hypoglycemia. The UKPDS found that an episode of hypoglycemia occurred annually in 2.3% of patients, predominantly those receiving insulin therapy, regardless of the intensity of glycemic control.5 Achieving glycemic control with diet and exerciseNutritional guidelines for patients who have type 2 diabetes are intended to minimize vascular disease, although many of these patients are overweight and should be encouraged to eat fewer calories and exercise more often.6 The patient's diet and exercise program should be directed at lowering BP, improving the lipid profile, and maintaining normoglycemia (see Table 2). A healthful diet that includes carbohydrate, protein, and fat, together with modest and regular exercise, should help most patients meet their weight, glycemic, and lipid goals.6 The patient is more likely to succeed on a plan that includes the recommended number of daily servings from the five main food groups and allows the patient to choose from a variety of foods. The patient should understand appropriate portion sizes and how to match goal weight with activity and blood glucose levels. Meeting with a trained dietitian can be an important part of the patient's medical care.
Regular exercise has been shown to lower blood glucose levels, reduce cardiovascular risk, promote weight loss, and increase well-being.3 Exercise can improve lipid profiles and insulin sensitivity and can help reduce insulin resistance in obese patients.7 Before beginning an exercise program, a previously sedentary patient should undergo a complete evaluation, including screening for CVD and any other complications associated with diabetes, and the program should be tailored accordingly. The patient should be evaluated after 6 weeks on a diet and exercise regimen;8 any patient whose blood glucose and A1C values are within normal limits at this point should continue with the regimen and return for evaluation every 3 months. PharmacotherapyDrug therapy should be initiated if the patient's plasma or blood glucose level and A1C values exceed normal limits after 6 weeks of an appropriate diet and exercise program. The patient's self-monitored blood glucose (SMBG) diary also should be reviewed at the 6-week follow-up, if the patient has been using a self-monitoring device. Note that an FPG that is greater than 200 mg/dL warrants immediate initiation of oral drug therapy at the time of diagnosis, regardless of whether the patient has symptoms. A fingerstick blood glucose testing kit and monitor is an excellent tool for providing a rough estimate of control, although results of SMBG tests are typically approximately 10 mg/dL higher than plasma glucose levels. The A1C value is the primary tool used for monitoring glycemic control over time.8 The decision to use monotherapy or combination therapy depends on the degree of hyperglycemia and the A1C concentration at the first follow-up visit. An oral hypoglycemic agent will typically decrease the blood glucose level 10 to 60 mg/dL and the A1C concentration by 1 or 2 percentage points, making monotherapy using an oral hypoglycemic agent appropriate for a patient with a fasting blood glucose level (FBG) between 100 and 160 mg/dL or an A1C concentration that is between 6.5% and 8.5%. Combination therapy should be considered in a patient with an FBG level that is higher than 160 mg/dL or an A1C concentration that is greater than 8.5%. A patient beginning drug therapy should continue with a diet and exercise program, have regular checkups every 8 to 12 weeks, and continue to receive therapy and counseling to reduce the risk of developing CVD, hypertension, and microvascular complications. Reevaluate the patient 8 to 12 weeks after initiating drug therapy to monitor its effects, assess patient adherence, and address any patient concerns or questions that are likely to arise with the new treatment.8 By this time patients will have some experience with self care and are likely to have questions about A1C goals, blood glucose goals using their blood glucose meter before meals, bedtime goals when using their blood glucose meter, and diet and drug effects. Now is the time to discuss patients' fears, explain the dangers of diabetes and how you are going to closely follow patients to ensure that they receive the best care to minimize complications relating to their disease, and review any possible adverse events in their treatment. If A1C values remain elevated at the first checkup, think about adding another drug to monotherapy or combination therapy. Although insulin may also be added at this time, its use is typically deferred until a combination of at least two oral agents have been tried (see "When to add insulin," below). Specific indications and contraindications are listed in Table 3.
Oral hypoglycemic agentsInsulin secretogogues The sulfonylureas are effective hypoglycemic agents that work by stimulating the pancreas to produce more insulin. Drugs in this class that are frequently used for patients with newly diagnosed diabetes, or in patients who have had the diagnosis of type 2 diabetes for fewer than 5 years, include glyburide (Diabeta, Glynase, Micronase), glipizide (Glucotrol, Glucotrol XL), and glimepiride (Amaryl). The meglitinides (repaglinide [Prandin] and nateglinide [Starlix]) are also secretogogues and are appropriate in newly diagnosed diabetes and when postprandial glucose levels are elevated.8-11 Insulin sensitizers The biguanide metformin (Glucophage, Glucophage XR) decreases hepatic glucose production and intestinal glucose absorption, and increases insulin sensitivity. Metformin may also decrease lipid levels, and there is some evidence of weight losswhich may contribute to improved insulin resistanceassociated with use of this drug. Metformin is effective in overweight or obese patients who have insulin resistance. The thiazolidinediones increase insulin sensitivity in muscle and adipose tissue and decrease hepatic glucose production. Drugs in this class include rosiglitazone (Avandia) and pioglitazone (Actos). Use of these drugs should be considered in patients who are insulin resistant and overweight.8-10 Drugs used in combination therapy should each have a different mechanism of action, such as a secretogogue combined with an insulin sensitizer rather than two secretogogues together. There is no evidence to support combination therapy using two or more drugs having similar actions. When to add insulinInsulin is necessary for normal carbohydrate, protein, and fat metabolism.8-10,12 Although insulin production is often adequate early in diabetes, exogenous insulin supplementation may be necessary as the disease progresses and insulin production slows. An evening or bedtime dose of insulin should be considered when combination therapy using two or three oral hypoglycemics with different actions does not adequately lower the blood glucose level.8-10 Table 4 outlines acceptable combination therapy with insulin.
Consider adding insulin when glucose toxicity decreases the effectiveness of other therapeutic regimens. A rising glycemic level despite the maximum dosage of oral hypoglycemic agents, dietary compliance, and exercise suggests glucose toxicity, a condition in which chronically high glucose levels cause the deterioration of pancreatic ß-cells, resulting in the eventual need for insulin. Insulin can be used in such cases, sometimes temporarily, to improve glycemic control and to regulate decompensated patients.4 The addition of insulin to a combination oral hypoglycemic regimen should target the patient's glycemic pattern; an evening or bedtime dose of an intermediate- or long-acting insulin is usually an appropriate starting point (see Table 5). Options include using a bedtime dose of intermediate-acting insulin (isophane insulin [NPH] or insulin zinc [Lente]) or long-acting or basal insulin (eg, insulin glargine [Lantus], insulin zinc, extended [Ultralente]). More intensive therapy (a dose of 75/25 human insulin lispro [Humalog] or 70/30 insulin) may be needed for postprandial hyperglycemia or for tighter control of blood glucose.9 Intensive therapy may include multiple insulin injections throughout the day depending on preprandial and postprandial blood glucose levels.
The suggested starting dosage for insulin is 0.1 to 0.2 U/kg of ideal body weight, titrating the dosage as needed depending on the patient's response. Preprandial and postprandial blood glucose levels guide titration until a target FBG goal is met. If the target FBG level is not achieved, adding multiple doses of short-, intermediate- or long-acting insulin, or adding an insulin sensitizing agent such as metformin or pioglitazone, is warranted.9,10 Averting the complications of type 2 diabetesCardiovascular disease CVD is the leading cause of death among patients with diabetes,13 and the risk of a new MI in a patient with diabetes is equal to the risk of recurrent MI in a nondiabetic patient.13 Because diabetes is such a major risk factor for CVD, aggressive treatment of all CVD risk factorsnot just the diabetesis strongly recommended. Hypertension is a common condition in patients who have diabetes. Obesity, high lipid levels, lack of exercise, and ethnicity all contribute to the development of hypertension, which itself can contribute to CVD and the microvascular disease that causes so much morbidity in these patients. Hypertension has been linked to nephropathy, retinopathy, and peripheral vascular disease; thus, in addition to diminishing the risk of CVD, controlling hypertension can also reduce the risk of developing other comorbidities.5,13-17 The ADA recommends BP screening at routine visits, with target levels below 130 mm Hg systolic and 80 mm Hg diastolic; higher readings require intervention. A patient whose systolic BP is 130 to 139 mm Hg and diastolic BP is 80 to 89 mm Hg should be counseled on exercise, diet, and other lifestyle changes. Higher readings warrant initiation of an antihypertensive agent. Although the ADA does not recommend one class of antihypertensive over another for initial therapy, its Expert Committee on the Diagnosis and Classification of Diabetes Mellitus recognizes the definite advantage in ACE inhibitors and angiotensin-receptor blockers (ARBs) in protecting against nephropathy.14 The first drug used may be an ACE inhibitor, an ARB, a ß-blocker, or a diuretic.18 An ACE inhibitor or ARB should, of course, be considered first in patients who have microalbuminuria, clinical albuminuria, or nephropathy. An ACE inhibitor may be considered for the diabetic patient who is older than 55 years and has other cardiac risk factors, whether or not the patient has hypertension. A patient who has had a cardiac event such as an MI should begin ß-blocker therapy. BP reduction, particularly in elderly patients, should be gradual to avoid complications. Begin with a low dosage of an antihypertensive and gradually increase it as the clinical situation suggests. Monitor renal function and serum potassium in patients who are starting on ACE inhibitor therapy or ARB therapy.10,12,14 Hyperlipidemia is common in patients who have diabetes, and because poor lipid profiles are associated with CVD, lipid management is an important part of diabetes care. Reducing intake of saturated fats and cholesterol, engaging in exercise, and achieving and maintaining an ideal weight are the foundation of lipid management. In patients who do not have coronary heart disease, the LDL cholesterol level should be 100 mg/dL or lower, with drug therapy recommended in patients whose LDL level is greater than 129 mg/dL.19 Medical nutritional therapy (MNT) and exercise are recommended for patients whose LDL levels are between 100 and 129 mg/dL; statin therapy should not be initiated until MNT has proven ineffective. Patients who have low HDL cholesterol and LDL levels between 100 and 129 mg/dL should be started on both MNT therapy and pharmacotherapy with a fibric acid derivative such as gemfibrozil (Lopid) or fenofibrate (Tricor). The ADA recommends a fibric acid derivative along with diet and exercise for low HDL levels and for LDL levels that are between 100 and 129 mg/dL. Aspirin therapy to reduce the risk of stroke and MI is recommended for diabetic patients who are older than 40 and have at least one cardiac risk factor, and in younger diabetic patients who have CVD.14 The recommended dosage is 75 to 324 mg/d. Aspirin use is not recommended in patients younger than 21 years because of the increased risk of Reye's syndrome. Nephropathy Diabetic nephropathy occurs in 20% to 40% of patients with diabetes and is the single leading cause of end-stage renal disease. The ADA recommends screening for nephropathy when the diagnosis of type 2 diabetes is made and at each annual exam. Intensive glycemic control has been shown to delay the onset of microalbuminuria, an early stage of diabetic nephropathy.20 Evidence of microalbuminuria in a diabetic patient who also has hypertension warrants the use of an ACE inhibitor or ARB, and the ADA notes that the ACE inhibitors and ARBs used in the treatment of hypertension have a significant advantage over other antihypertensives in delaying the progression of microalbuminuria to clinical albuminuria. Serum potassium levels should be monitored for early signs of hyperkalemia in patients taking these drugs.14 In addition, improved lipid profiles have been associated with reduced proteinuria, and data suggest that a moderate restriction in dietary protein and intensive BP control in patients with frank proteinuria are beneficial. Diabetic retinopathy The leading cause of blindness in the United States is diabetic retinopathy. Poor glycemic control and poorly treated hypertension are significant contributors.4 The ADA prevention recommendations center on intensive glycemic control, BP control, early referral of diabetic patients with macular edema, and laser therapy to reduce vision loss.5,14-17 An annual dilated eye examination by an optometrist or ophthalmologist should be an integral part of the multidisciplinary approach to care (see Figure 1).
Peripheral neuropathy Early recognition of peripheral neuropathy can reduce the risk of foot ulceration and amputation. A comprehensive foot examination performed at the time of the diagnosis of diabetes includes a visual inspection of the patient's feet and patient education about the risk of ulcer, infection, bone changes, and the damage caused by peripheral neuropathy (see Figure 2). A foot examination should be performed annually or at each visit for patients with known peripheral neuropathy.14
ConclusionEarly diagnosis offers the best hope of achieving timely intensive glycemic control to reduce the occurrence of diabetic complications and comorbidities.
REFERENCES 1. American Diabetes Association. Screening for diabetes. Diabetes Care. 2002;25(suppl 1):S21-S24. 2. Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care. 2002;25(suppl 1):S5-S20. 3. American Diabetes Association. Components of the initial visit. Diabetes Care. 2002;25(suppl 1):S36. 4. Skyler JS. Insulin therapy in type II diabetes: who needs it, how much of it, and for how long? Postgrad Med. February 1997;101:85-90,92-94, 96. 5. American Diabetes Association. Implications of the United Kingdom Prospective Diabetes Study. Diabetes Care. 2002; 25(suppl 1):S28-S32. 6. Webster MW, Scott RS. What cardiologists need to know about diabetes. Lancet. 1997;350(suppl 1):SI23-SI28. 7. American Diabetes Association. Diabetes mellitus and exercise. Diabetes Care. 2002;25(suppl 1):S64. 8. Hawkins D, Bradberry JC, Cziraky MJ, et al. National Pharmacy Cardiovascular Council treatment guidelines for the management of type 2 diabetes mellitus: toward better patient outcomes and new roles for pharmacists. Pharmacotherapy. 2002;22:436-444. 9. Abrahamson M, Beaser R, Blair L, et al. Clinical guideline for pharmacological management of type 2 diabetes 2/11/03. Joslin Diabetes Center and Joslin Clinic, Inc. Available at: https://diabetesmanagement.joslin.org/Guidelines/Pharm_ ClinGuide.pdf. Accessed November 13, 2003. 10. The Therapeutic Research Center. Oral agents in the treatment of type 2 diabetes. Pharmacist's Letter/Prescriber's Letter. 2002:18. Detail document no. 180608. 11. What new oral medications are available for type 2 diabetes? Joslin Diabetes Center. Available at https://www.joslin.harvard.edu/education/library/oral_agents.shtml . Accessed December 11, 2003. 12. American Diabetes Association. Insulin administration. Diabetes Care. 2002;25(suppl 1):S112-S115. 13. The Diabetes Prevention Program Research Group. Costs associated with the primary prevention of type 2 diabetes mellitus in the diabetes prevention program. Diabetes Care. 2003; 26:36-47. 14. American Diabetes Association. Standards of medical care for patients with diabetes mellitus. Diabetes Care. 2002;25(suppl1): S33-S49. 15. Turner RC, Millns H, Neil HA, et al. Risk factors for coronary artery disease in non-insulin dependent diabetes mellitus: United Kingdom Prospective Diabetes Study (UKPDS: 23). BMJ. 1998;316:823-828. 16. Adler AI, Stratton IM, Neil HA, et al. Association of systolic blood pressure with macrovascular and microvascular complications of type 2 diabetes (UKPDS 36): prospective observational study. BMJ. 2000;321:412-419. 17. American Diabetes Association. Treatment of hypertension in adults with diabetes. Diabetes Care. 2002;25(suppl 1):S71-S73. 18. Stratton IM, Adler AI, Neil HA, et al. Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): Prospective observational study. BMJ. 2000;321:405-412. 19. American Diabetes Association. Evidence-based nutrition principles and recommendations for the treatment and prevention of diabetes and related complications. Diabetes Care. 2003; 26(suppl 1):S51-S61. 20. National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC). Kidney disease of diabetes. NIH publication no. 04-3925; November 2003. Available at: http://www.niddk.nih.gov/health/kidney/pubs/kdd/kdd.htm . Accessed December 11, 2003.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||