Classification and diagnosis of diabetes mellitus
(1) Classification of increased risk of diabetes mellitus (prediabetes)
● Asymptomatic adults who are overweight or obese (BMI ≥ 25 kg/m2 or ≥ 23 kg/m2 in Asian Americans) and have a combination of 1 or more other risk factors for diabetes should be considered for assessment of future diabetes risk starting with testing at any age. For all patients, especially those who are overweight or obese, screening should begin at age 45 years.
● If the test results are normal, it is reasonable to repeat the test at least every 3 years.
● Prediabetes can be screened using A1c, fasting glucose, or 75g OGTT2h glucose.
●In people with prediabetes, cardiovascular disease (CVD) risk factors should be evaluated and treated.
● Screening for prediabetes should be considered in children and adolescents who are overweight or obese and have a combination of 2 or more other risk factors for diabetes.
(2) Type 1 diabetes mellitus
● Inform relevant relatives of patients with type 1 diabetes to screen for the risk of type 1 diabetes, but only at clinical research institutions.
(3) Type 2 diabetes mellitus
● Screening for type 2 diabetes should be considered from any age in asymptomatic adults who are overweight or obese (BMI ≥ 25 kg/m2 or ≥ 23 kg/m2 in Asian Americans) and have a combination of 1 or more other risk factors for diabetes. Screening should begin at age 45 for all patients, especially those who are overweight or obese.
● If the test results are normal, it is reasonable to review the test at least every 3 years.
●Diabetes can be screened using A1c, fasting glucose, or 75g OGTT2h glucose.
●In patients with diabetes, cardiovascular disease (CVD) risk factors should be evaluated and treated.
● Screening for type 2 diabetes should be considered in children and adolescents who are overweight or obese and have a combination of 2 or more risk factors for diabetes.
(4) Gestational diabetes
● For individuals with risk factors, screen for undiagnosed type 2 diabetes at the first prenatal visit using standard diagnostic methods.
● For pregnant women without a history of diabetes, screen for gestational diabetes mellitus (GDM) at 24 to 28 weeks of gestation.
● For women with gestational diabetes, screen for permanent diabetes using OGTT and non-gestational diabetes diagnostic criteria at 6 to 12 weeks postpartum.
● Women with a history of gestational diabetes should be screened for the development of diabetes or prediabetes at least every 3 years.
● Women with a history of gestational diabetes mellitus who are prediabetic should receive lifestyle interventions or metformin therapy to prevent diabetes.
(5) Cystic fibrosis-related diabetes mellitus (CFRD)
●All patients with cystic fibrosis should be screened annually for CFRD using OGTT starting at age 10 years. b Screening for CFRD with A1c is not recommended.
● Patients with CFRD should be treated with insulin to achieve individualized glycemic control goals.
● For patients with IGT fibrosis without diagnosed diabetes, pre-meal insulin therapy should be considered for weight maintenance.
● Annual monitoring for diabetic complications starting 5 years after CFRD diagnosis is recommended.
Initial assessment and diabetes management plan
(1) Medical assessment
● Patients with type 1 diabetes should be considered for screening for autoimmune disease (e.g., thyroid disease, celiac disease) as appropriate.
(2) Common comorbidities
● Consider evaluation and treatment of common comorbidities associated with diabetes (e.g., depression, obstructive sleep apnea).
Basics of diabetes treatment: education, nutrition, physical activity, persuasion to quit smoking, psychotherapy, and immunizations
(1) Diabetes self-management education and support
● Patients with diabetes should receive diabetes self-management education (DSME) and diabetes self-management support (DSMS) according to the National Diabetes Self-Management Education and Support Standards as needed after diabetes is diagnosed.
● Effective self-management and quality of life are the primary goals of DSME and DSMS and should be assessed and monitored as part of treatment.
● DSME and DSMS should include psychological counseling, as good mood is associated with a good prognosis for diabetes.
●People with prediabetes are appropriate for DSME and DSMS programs to receive education and support to improve and maintain behaviors that can prevent or delay the onset of diabetes.
Because DSME and DSMS can be cost effective and improve prognosis B, DSME and DSMS should be fully reimbursed by third-party payers.
(2) Physical activity
● Children with diabetes or prediabetes should be encouraged to engage in at least 60 minutes of physical activity per day.
● Adults with diabetes should engage in at least 150 minutes of moderate-intensity aerobic exercise (50% to 70% of maximum heart rate) at least 3 days per week, with no more than 2 consecutive days without exercise.
● Current evidence supports that all individuals (including those with diabetes) should be encouraged to reduce quiet sitting time, especially by avoiding prolonged quiet sitting (>90 minutes).
● Encourage patients with type 2 diabetes without contraindications to perform endurance exercise at least 2 times per week.
(3) Smoking cessation
● Advise all patients not to smoke or use tobacco products.
● Smoking cessation counseling and other forms of treatment are a routine part of diabetes treatment.
Psychological assessment and treatment
● Assessment of psychological and social status is part of the ongoing treatment of diabetes.
● Psychological screening and follow-up includes, but is not limited to: attitudes about the disease, expectations about treatment and prognosis, affective/emotional status, general and diabetes-related quality of life, resources (financial, social, and emotional), and psychiatric history.
● Routine screening for psychological problems such as depression and diabetes-related depression, anxiety, eating disorders, and cognitive impairment.
● Older patients with diabetes (≥65 years) should be prioritized for screening and treatment of depression.
● Patients with diabetes mellitus with depression should receive a stepwise collaborative treatment approach for depression.
Immunizations
● Children and adults with diabetes should be routinely vaccinated as the general population.
● Patients with diabetes aged ≥6 months should receive annual influenza vaccination.
● All diabetic patients ≥2 years of age are required to receive pneumococcal polysaccharide vaccine 23 (PPSV23).
● Patients ≥65 years of age who have not been previously vaccinated should receive pneumococcal conjugate vaccine 13 (PCV13), followed by PPSV23 6 to 12 months after the initial vaccination.
● Patients aged ≥65 years who have been previously vaccinated with PPSV23 should be vaccinated with PCV13 ≥12 months later.
● Patients with diabetes aged 19 to 59 years who have not previously received hepatitis B vaccination should be vaccinated.
● Patients with diabetes aged ≥60 years who have not received hepatitis B vaccine should be considered for vaccination.
Prevention or delay of type 2 diabetes
● Patients with abnormal glucose tolerance (IGT) A, impaired fasting glucose (IFG), or A1c between 5.7 and 6.4% should be referred to an intensive diet and physical activity behavioral counseling program unit with the goal of losing 7% of body weight and increasing moderate intensity physical activity (e.g., brisk walking) to at least 150 minutes per week.
● Regular follow-up counseling is important.
● Based on the cost-effectiveness of diabetes prevention, the cost of these support programs should be paid for by a third party.
●For women with IGTA, IFGE or A1c between 5.7 and 6.4% E, especially those with BMI > 35 kg/m2, age < 60 years and a history of GDM, consider metformin treatment for the prevention of type 2 diabetes.
● It is recommended that patients with prediabetes should be monitored annually to watch for progression to diabetes.
● Screening and treatment of modifiable CVD risk factors is recommended.
● Diabetes self-management (DSME) and educational support (DSMS) programs are appropriate for people with prediabetes to receive education and support to develop and maintain behaviors that can prevent or delay the onset of diabetes. c
Blood glucose goals
(1) Assessment of glycemic control
● For patients with low insulin injections and non-insulin therapy, SMBG as part of the educational component may be helpful to guide treatment B and/or patient self-management.
● After prescribing SMBG, ensure that patients receive ongoing instruction and periodic assessment of their SMBG technique and SMBG results and their ability to adjust therapy with SMBG data.
● Patients treated with multiple daily insulin injections (MDI) or insulin pumps should perform self-monitoring of blood glucose (SMBG), testing at least before every meal and occasionally after meals, at bedtime, before exercise, after suspected hypoglycemia, after treatment of hypoglycemia until blood glucose normalizes, and before critical tasks (e.g., driving operations).
● For some adults (age ≥25 years) with type 1 diabetes, the correct use of ambulatory glucose monitoring (CGM) in combination with intensive insulin therapy is an effective way to lower A1c.
● Although the evidence for A1c reduction with CGM is not strong in pediatric, adolescent, and young adult patients, CGM may be helpful in this population. Success is associated with adherence to ongoing use of this instrument.
● For patients with asymptomatic hypoglycemia and/or frequent hypoglycemia, CGM may be an adjunct to SMBG.
●Because compliance with CGM is highly variable, the patient’s ability to consistently apply CGM should be assessed before prescribing.
● When prescribing CGM, enhanced diabetes education, training and support are needed for optimal CGM implementation and sustained use.
(2) A1c testing
● A1c should be tested at least twice a year for patients who are on treatment (and have stable glycemic control).
● For patients who change their treatment regimen or whose glycemic control is not up to standard, A1c should be tested four times a year.
●Application of instant A1c test helps to change the treatment plan in time.
(3) A1c target
●Reducing A1c to about 7% or less can reduce diabetic microvascular complications, and if good glycemic control is achieved immediately after the diagnosis of diabetes, it can reduce distant macrovascular disease. Therefore, a reasonable A1c control goal for most non-pregnant adults is <7%.
● For some patients without significant hypoglycemia or other treatment side effects, it may also be reasonable to recommend a more stringent A1c goal (e.g., <6.5%). These patients may include those with type 2 diabetes who have a short duration of diabetes, are treated with lifestyle or metformin only, have a long life expectancy, or do not have significant cardiovascular disease (CVD).
For patients with longer duration of diabetes who have a history of severe hypoglycemia, limited life expectancy, advanced microvascular or macrovascular disease complications, more co-morbidities, and who have difficulty meeting glycemic targets despite diabetes self-management education (DSME), appropriate glucose testing, or multiple effective doses of glucose-lowering medications, including insulin, a more lenient A1c target (e.g., <8% ) may be reasonable.
(4) Hypoglycemia
● Patients at risk for hypoglycemia should be asked about symptomatic and asymptomatic hypoglycemia at each follow-up visit.
● In awake hypoglycemic patients, glucose (15 to 20 g) is the treatment of choice, although any form of carbohydrate containing glucose is available. If the SMBG remains hypoglycemic after 15 minutes, the above treatment should be repeated. after the SMBG blood glucose is normal, the patient should eat a meal or snack to prevent recurrence of hypoglycemia.
● Glucagon should be prescribed to all patients at risk of severe hypoglycemia, and caregivers or family members should be instructed on how to administer glucagon. Glucagon administration is not limited to health care professionals.
● Patients with diabetes who have asymptomatic hypoglycemia or have had 1 or more episodes of severe hypoglycemia should have their treatment plan reevaluated.
● Patients treated with insulin who have asymptomatic hypoglycemia or episodes of severe hypoglycemia are advised to relax glycemic control goals and strictly avoid recurrent hypoglycemia in recent weeks to partially reverse asymptomatic hypoglycemia and reduce the risk of future hypoglycemia.
● Ongoing assessment of cognitive function is recommended if low and/or declining cognitive function is noted, and clinicians, patients and caregivers should be on high alert for hypoglycemia.
Blood glucose treatment options
(1) Pharmacological treatment of type 1 diabetes mellitus
● Most patients with type 1 diabetes should be treated with MDI injections (three to four daily basal and mealtime insulin injections) or continuous subcutaneous insulin infusion (CSII) regimens.
● Most patients with type 1 diabetes should be educated on how to adjust their pre-meal insulin dose based on carbohydrate intake, pre-meal glucose, and expected exercise.
● Most patients with type 1 diabetes should use insulin analogues to reduce the risk of hypoglycemia.
(2) Pharmacological treatment of type 2 diabetes
● Metformin is the drug of choice for initiating treatment of type 2 diabetes if it is not contraindicated and is tolerated.
●In newly diagnosed type 2 diabetes mellitus patients with significant symptoms of hyperglycemia and/or significantly elevated blood glucose or A1c levels, consider insulin therapy at the outset with or without the addition of other medications.
● Add a second oral medication, glucagon-like peptide-1 (GLP-1) receptor agonist, or basal insulin if the maximum tolerated dose of non-insulin monotherapy does not achieve or maintain the A1C goal at 3 months.
● A patient-centered regimen should be used to guide drug selection. Factors to consider include effectiveness, cost, potential side effects, impact on weight, co-morbidity, risk of hypoglycemia, and patient preference.
Because type 2 diabetes is a progressive disease, many patients with type 2 diabetes will eventually require insulin therapy.
(3) Weight reduction surgery
Bariatric surgery may be considered for adults with type 2 diabetes with a BMI > 35 kg/m2, especially if the diabetes or associated co-morbidities are difficult to control with lifestyle and medication.
●Patients with type 2 diabetes who have undergone bariatric surgery require long-term lifestyle support and medical monitoring.
● Although small studies have shown that patients with type 2 diabetes with a BMI between 30 and 35 kg/m2 also have better glycemic control when they undergo bariatric surgery, there is a lack of sufficient evidence to recommend surgery for patients with a BMI <35 kg/m2.
Cardiovascular disease and risk management
(1) Hypertension/blood pressure control
Screening and diagnosis
● Patients with diabetes should have their blood pressure measured at each follow-up visit. Patients with elevated blood pressure should have repeat measurements on another day to confirm.
Objectives
● The systolic blood pressure control goal for patients with diabetes combined with hypertension should be <140 mmHg.
● Lower systolic blood pressure goals, such as <130 mmHg, may be appropriate for some patients, such as younger patients, if they do not increase the burden of treatment.
● Diabetic patients should have diastolic blood pressure control of <90 mmHg.
● A lower systolic blood pressure goal, such as <80 mmHg, may be appropriate for some patients, such as younger patients, if it does not increase the burden of treatment.
Treatment
● Lifestyle changes to lower blood pressure are recommended for patients with blood pressure >120/80 mmHg.
● Patients with definite blood pressure ≥ 140/90 mmHg should receive immediate medication in addition to lifestyle treatment and prompt adjustment of medication dose to bring blood pressure up to standard.
Lifestyle treatment for elevated blood pressure includes weight loss in overweight individuals; dietary regimens for dietary interruption of hypertension (DASH) (including reduced sodium intake and increased potassium intake); moderate alcohol intake; and increased physical activity.
● The medication regimen for patients with diabetes mellitus and hypertension should include an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor antagonist (ARB) B. If one class of medication is not tolerated, it should be replaced with another class of medication.
● To achieve blood pressure control, it is often necessary to combine multiple drugs (including maximum doses of thiazide diuretics and ACEI/ARB).
● If ACE inhibitors, ARBs, or diuretics are already being used, blood creatinine/estimated glomerular filtration rate (eGFR) and blood potassium levels should be monitored.
In pregnant women with diabetes mellitus and chronic hypertension, a blood pressure target of 110-129/65-79 mm Hg is recommended for the long-term health of the mother and to reduce fetal developmental damage. ACE inhibitors and ARBs are contraindicated during pregnancy.
(2) Dyslipidemia/Lipid Management
Screening
● It is reasonable for adults to be screened for lipids at first diagnosis, initial medical evaluation, and/or when they reach the age of 40 years, and to be reviewed periodically thereafter (e.g., every 1 to 2 years).
Treatment Recommendations and Goals
● In patients with diabetes mellitus, lifestyle interventions are recommended to improve lipids, including: reducing saturated fat, trans fat, and cholesterol intake; increasing n-3 fatty acid, viscous fiber, and phytosterols/sterols intake; reducing body weight (if indicated); and increasing physical activity.
● Intensify lifestyle therapy and optimize glycemic control in patients with elevated triglyceride levels (TG ≥1.7 mmol/L) and/or reduced HDL cholesterol (<1.0 mmol/L in men and <1.3 mmol/L in women). c Evaluate secondary causes and consider pharmacotherapy to reduce the risk of pancreatitis in patients with fasting triglycerides ≥5.7 mmol/L.
● Patients of all ages with diabetes mellitus with coronary artery disease should be treated with high-intensity statins in addition to lifestyle interventions.
● For patients aged <40 years with other cardiovascular risk factors, consider moderate or high-intensity statin therapy in addition to lifestyle interventions.
● For patients aged 40 to 75 years with diabetes without other cardiovascular risk factors, consider moderate-intensity statin therapy based on lifestyle interventions.
● Patients with diabetes mellitus aged 40-75 years with other cardiovascular risk factors should be considered for high-intensity statin therapy based on lifestyle interventions.
For patients aged >75 years without other cardiovascular risk factors, consider moderate-intensity statin therapy based on lifestyle interventions.
For patients >75 years of age with other cardiovascular risk factors, consider moderate- or high-intensity statin therapy in addition to lifestyle interventions.
● In clinical practice, providers may need to adjust the intensity of statin therapy based on individualized patient response to the drug (e.g., side effects, tolerability, LDL cholesterol levels).
●Cholesterol laboratory testing may be useful to monitor adherence to therapy, but may not be necessary for patients who are stable on therapy.
● Combination therapy (statin/beta and statin/niacin) does not provide additional cardiovascular benefit beyond that of statin monotherapy and is not usually recommended.
● Statin therapy is contraindicated during pregnancy.
(3) Antiplatelet agents
Consider aspirin primary prophylaxis (dose 75-162 mg/d) in patients with type 1 and type 2 diabetes (10-year risk >10%) who have increased cardiovascular risk. This includes most men >50 years of age or women >60 years of age who have a combination of at least one other major risk factor (family history of CVD, hypertension, smoking, dyslipidemia, or proteinuria).
● Aspirin should not be recommended for CVD prevention in adults with diabetes at low risk for CVD (10-year CVD risk <5%, e.g., men <50 years of age or women <60 years of age with no other major CVD risk factors) because the potential side effects of bleeding may outweigh the potential benefit.
● Patients in this age group with multiple other risk factors (e.g., 10-year risk of 5-10%) require clinical judgment.
● Patients with diabetes mellitus with a history of CVD are treated with aspirin (dose 75 to 162 mg/d) as secondary prevention.
● Diabetic patients with a history of CVD and aspirin allergy should be treated with clopidogrel (dose 75 mg/d).
● After the occurrence of acute coronary syndrome, dual antiplatelet therapy for one year is reasonable.
(4) Coronary heart disease
Screening
● Routine screening for coronary artery disease is not recommended for asymptomatic patients because routine screening for coronary artery disease does not improve outcomes as long as treatment is given for cardiovascular risk factors.
Treatment
● Patients with a confirmed diagnosis of concomitant CVD are treated with aspirin and statin (if not contraindicated) A, and ACEIC, is considered to reduce the risk of cardiovascular events.
● In patients with prior myocardial infarction, beta-blockers should be continued for at least 2 years after the infarction.
● Avoid thiazolidinediones in those with symptoms of heart failure.
● For people with stable congestive heart failure (CHF), metformin can be applied if renal function is normal. Metformin should be avoided in patients with unstable CHF or hospitalized for CHF.
Microvascular complications and foot therapy
(1) Nephropathy
General recommendations
● Optimize glycemic control to reduce the risk of nephropathy or to delay the progression of diabetic kidney disease.
● Optimize blood pressure control to reduce the risk of nephropathy or to delay the progression of diabetic kidney disease.
Screening
● Urinary albumin (e.g., urinary albumin creatinine ratio, UACR) and estimated glomerular filtration rate (eGFR) should be quantitatively assessed at least annually from diagnosis in patients with type 1 diabetes and all patients with type 2 diabetes for ≥5 years.
Treatment
● ACEI or ARB is not recommended as primary prevention of diabetic kidney disease in diabetic patients with normal blood pressure and UACR (<30 mg/g).
● Except during pregnancy, ACEI or ARB classes are recommended for the treatment of patients with moderately elevated (30-299 mg/d) C or urinary albumin excretion rate ≥300 mg/d.
● For those applying ACE inhibitors, ARBs, and diuretics, monitor serum creatinine and blood potassium levels to observe for creatinine elevation and potassium changes.
●Continuous monitoring of UACR in patients with albuminuria is reasonable in order to assess the progression of diabetic kidney disease.
● Evaluate and treat potential complications of CKD when estimated GFR (eGFR) is <60 ml/min/1.73 m2.
● Patients should be referred to an experienced nephrologist if the cause of nephropathy is unclear, difficult to treat, or in cases of advanced kidney disease.
Nutrition
● For patients with diabetic kidney disease, it is not recommended to reduce protein intake below the recommended daily intake (0.8g/kg/d) (based on ideal body weight), as this does not alter the course of glycemic control, cardiovascular risk factor control, or GFR decline.
(2) Retinopathy
General recommendations
● Optimize glycemic control to reduce the risk of diabetic retinopathy or delay its progression.
● Optimize blood pressure control to reduce the risk or slow the progression of diabetic retinopathy.
Screening
● Adults with type 1 diabetes should receive a comprehensive post-dilated eye examination by an ophthalmologist or optometrist within 5 years of the onset of diabetes.
Patients with type 2 diabetes should receive a comprehensive post-dilated comprehensive eye examination by an ophthalmologist or optometrist as soon as possible after diagnosis.
If one or more eye exams are normal, consider having an exam every 2 years. Patients with type 1 and type 2 diabetes who have diabetic retinopathy should be examined by an ophthalmologist or optometrist once a year. If retinopathy progresses or threatens vision, the frequency of exams needs to be increased.
High-quality fundus photography can detect most clinically significant diabetic retinopathy. The films should be reviewed by a trained ophthalmologist. Although retinal photography can be used as a screening tool for retinopathy, it is not a substitute for a comprehensive ophthalmologic examination. After a comprehensive eye exam is performed, the frequency of follow-up visits is recommended by an ophthalmologist.
● Women with diabetes who are planning to become pregnant or are already pregnant should undergo a comprehensive eye examination for a comprehensive evaluation of the risk of developing and/or progressing diabetic retinopathy. Ophthalmologic examinations should be performed in the first trimester of pregnancy, followed by close follow-up throughout pregnancy and for 1 year after delivery.
Treatment
● Patients with any degree of macular edema, severe non-proliferative diabetic retinopathy (NPDR), or any proliferative diabetic retinopathy (PDR) should be referred immediately to an ophthalmologist with extensive experience in the treatment of diabetic retinopathy.
● In patients with high-risk PDR, clinically significant macular edema, and some severe NPDR, laser photocoagulation may reduce the risk of blindness.
● Diabetic macular edema is an indication for anti-vascular endothelial growth factor (VEGF) therapy.
● Since aspirin does not increase the risk of retinal hemorrhage, the presence of retinopathy is not a contraindication to aspirin therapy.
(3) Neuropathy
● All patients with type 2 diabetes should be screened for diabetic peripheral neuropathy (DPN) at diagnosis and 5 years after diagnosis of type 1 diabetes, using a simple clinical examination (e.g., 10-g nylon wire) and at least annually thereafter.
● Screening for signs and symptoms of cardiovascular autonomic neuropathy (CAN) (measurement of postural blood pressure changes, heart rate variability) should be considered in patients with advanced disease.
● Tight glycemic control is the only strategy with definite efficacy for preventing or delaying ADPN and CAN in patients with type 1 diabetes and may delay the progression of some type 2 diabetic neuropathies.
● Evaluate and treat patients to reduce symptoms of DPN-related pain B and autonomic neuropathy, thereby improving quality of life.
(4) Foot care
● Perform a comprehensive annual foot examination for all diabetic patients to identify risk factors for ulceration and amputation. Foot examination should include visual examination and assessment of foot artery pulsation.
● Patients with foot sensory loss, foot deformities and ulcers should have a foot examination at each visit.
● Education on diabetic foot self-protection should be given to all diabetic patients.
● Multidisciplinary management is recommended for patients with foot ulcers and high-risk feet (e.g., dialysis patients, Charcot foot, those with a history of foot ulcers or amputations).
● Those who smoke, have loss of protective sensation (LOPS), deformities, or previous lower extremity complications should be referred to a podiatrist for ongoing prophylaxis and lifelong monitoring.
● Initial screening for peripheral arterial disease (PAD) should include a history of claudication and assessment of the pes cavus.
● Those with significant claudication or an abnormal ankle-brachial index should undergo further vascular evaluation to consider exercise, medication, and surgical options.