Approach

For updates on the diagnosis and management of coexisting conditions during the coronavirus disease 2019 (COVID-19) pandemic, please see our topic "Management of coexisting conditions in the context of COVID-19".

The cornerstone of therapy for all patients with type 2 diabetes is a personalized management program that includes pharmacotherapy and ongoing self-management education by a diabetes education nurse or dietician.[2][70] Diabetes self-management education promotes diabetes self-care and supports beneficial lifestyle changes on an ongoing basis.[2] This requires general nutrition and health lifestyle knowledge and an individualized nutrition and exercise plan based on an initial assessment and treatment goals. Interventions that enhance self-management can significantly reduce diabetes distress.[71]

If antihyperglycemic pharmacotherapy is required, the choice of agents should be individualized, taking into account patient values and preferences, the likelihood that an agent reduces all-cause or cardiovascular mortality, renal effects, adverse effects, costs, and other factors.

About 80% of adults with type 2 diabetes have concurrent dyslipidemias or hypertension, 70% are overweight or obese, and around 15% are current smokers.[12] On average, adults with type 2 diabetes are up to twice as likely to die of stroke or myocardial infarction compared with those without diabetes, and they are more than 40 times more likely to die of macrovascular than microvascular complications of diabetes.[72][73][74] However, data indicate that adults with type 2 diabetes who optimally manage glucose, blood pressure (BP), lipids, smoking, and weight have a risk of major cardiovascular events that is not significantly above the risk of age and sex-matched non-diabetes peers.[75][76]

Therefore, care of adults with type 2 diabetes must include management of all major cardiovascular risk factors to individualized targets. In addition to glucose control, this includes smoking cessation, BP control, lipid control, antiplatelet use for patients with known coronary heart disease, and ACE inhibitors or angiotensin-II receptor antagonists for patients with chronic kidney disease (CKD) or proteinuria.[2][44][77] In addition, use of antihyperglycemic agents such as sodium-glucose co-transporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) agonists, which reduce cardiovascular or overall mortality, cardiovascular events, or CKD progression, may be especially beneficial in those with type 2 diabetes and at risk of/with established cardiovascular disease (CVD) or CKD regardless of the level of glucose management.[2][44][78][79][80]

Diet

Nutrition therapy involves limiting caloric intake to achieve recommended weight, while offering a diversified and appealing menu of food choices.[81] Nutrition advice needs to be tailored to the needs of each individual patient, preferably by a nutritionist.[2][33] The American Diabetes Association stresses that there is no ideal dietary macronutrient (carbohydrate, protein, and fat) distribution for people with diabetes, and that food plans should be individualized taking into account preferences and metabolic goals.[2] Low-carbohydrate diets appear to be beneficial for glycemic control in type 2 diabetes management.[82] Mediterranean diet and Dietary Approaches to Stop Hypertension (DASH) diets for people with hypertension have the best supporting evidence for use in patients with type 2 diabetes.[33] Saturated fat should be limited to <10% of calories.[33] Reducing sugary beverage consumption (including soda, energy drinks, and fruit juice) is of benefit to many patients.[33] Weight loss management programs with a healthy eating and physical activity plan resulting in an energy deficit have the potential for type 2 diabetes remission.[33][83][84] The Diabetes Remission Clinical Trial (DiRECT) of supported weight loss management for people diagnosed with type 2 diabetes within the previous 6 years, and a body mass index (BMI) of 27 kg/m² to 45 kg/m², found that almost half of participants achieved remission to a non-diabetic state and off antidiabetic drugs at 12 months.[83] At 2 years, more than a third of people with type 2 diabetes had sustained remission.[85]

Exercise and sleep

  • To improve glycemic control, assist with weight maintenance, and reduce cardiovascular risk, moderate physical activity is recommended as tolerated. The American College of Cardiology/American Heart Association has recommended that, in general, adults should engage in 3 to 4 sessions of aerobic physical activity per week, with each session lasting on average 40 minutes, and involving moderate- to vigorous-intensity physical activity.[86] Walking frequently in proper footwear is a recommended activity.[2]

  • In addition, gentle strength training that targets all major muscle groups may be beneficial if done for 20 minutes 2 to 3 times per week on nonconsecutive days. Patients with severe or symptomatic heart disease may require evaluation before increasing levels of physical activity.[2]

  • People should be encouraged to limit the amount of time they spend being sedentary by avoiding extended amounts of time spent sitting.[87]

  • Older adults may benefit from flexibility training and balance training 2 to 3 times/week (e.g., with yoga or tai chi).

  • An assessment of sleep duration and quality should be considered. Obesity, diabetes, hypertension, atrial fibrillation, and male sex are risk factors for sleep apnea, and inadequate sleep may affect glycemic control.[2]

Antihyperglycemic pharmacotherapy: initial considerations

HbA1c goals should be individualized.[88][89] For many patients, the goal HbA1c <7% is appropriate. However, HbA1c 7.0% to 7.9% may be more appropriate in some patients, such as those with advanced age, limited life expectancy, known CVD, high risk of severe hypoglycemia, or difficulty achieving lower HbA1c goals despite use of multiple antihyperglycemic medications and insulin.[2] Individualized HbA1c goals improve quality of life compared with uniform tight control.[89]

Pharmacotherapy is recommended to reduce risk of both microvascular (nephropathy, retinopathy, neuropathy) and macrovascular (myocardial infarction, stroke, peripheral vascular disease) complications, and is guided by HbA1c goals or a unique indication (presence of atherosclerotic CVD, heart failure, CKD).[2][78][79][80][90][91] Antihyperglycemic medications that reduce all-cause or cardiovascular mortality, or major cardiovascular events or renal complications in some patient subgroups are metformin, SGLT2 inhibitors, and GLP-1 agonists.[92][93][94][95]

In older studies such as ACCORD, ADVANCE, and the Veterans Affairs Diabetes Trial (VADT), use of multiple drugs to achieve near-normal HbA1c was either not beneficial or increased mortality in type 2 diabetes patients with CVD or high CVD risk.[96][97][98][99][100] However, SGLT2 inhibitors were not available and GLP-1 agonists were infrequently used in those studies.

Metformin is the recommended first-choice therapy at diagnosis in the absence of contraindications because of its safety profile and likely cardiovascular benefit.[90][92] Metformin may be safely used in patients with reduced estimated glomerular filtration rates (eGFRs), but it is contraindicated if eGFR <30 mL/minute/1.73 m².[2][78] Metformin should not be initiated if the eGFR is <45 mL/minute/1.73 m², and, for patients taking metformin whose eGFR falls to within the 30-45 mL/minute/1.73 m² range, continued use can be considered with close monitoring of renal function and a dose reduction.[78] People who are unable to take metformin due to contraindications or intolerance can either use an alternative noninsulin agent or start insulin therapy. Basal-bolus insulin is used as initial treatment (without metformin) for those with type 2 diabetes and very high initial glucose levels (>300 mg/dL).

In patients with diabetes without diagnosed CVD, if metformin is used as initial treatment and fails to achieve goals after 3 months, a second agent may be added based on individualized assessment of necessary clinical benefit, safety considerations, costs, and patient preference:[78]

  • SGLT2 inhibitor: canagliflozin, dapagliflozin, empagliflozin, or ertugliflozin

  • GLP-1 agonist: liraglutide, exenatide, lixisenatide, semaglutide, or dulaglutide

  • Dipeptidyl peptidase-4 (DPP-4) inhibitor: sitagliptin, saxagliptin, linagliptin, or alogliptin

  • Sulfonylurea: glimepiride or glipizide; meglitinides (e.g., repaglinide, nateglinide) are an alternative

  • Alpha-glucosidase inhibitor: acarbose or miglitol

  • Thiazolidinedione: pioglitazone or rosiglitazone

  • Insulin.

In patients with diabetes and with diagnosed CVD, heart failure, or CKD, metformin is used as initial treatment. Addition of a SGLT2 inhibitor or GLP-1 agonist is also recommended if not contraindicated, regardless of HbA1c and glycemic status, with choice of class dependent on comorbidity.[2] Diagnosed atherosclerotic CVD favors either SGLT2 or GLP-1 therapy, while heart failure favors SGLT2 therapy and CKD favors SGLT2 therapy, with some benefit being demonstrated for GLP-1 therapy.[2][78][79][101]

  • SGLT2 inhibitor: canagliflozin, empagliflozin, or dapagliflozin may be preferred.

  • GLP-1 agonist: liraglutide, semaglutide, or dulaglutide may be preferred.

There are many appropriate 3-agent combinations of glucose-lowering therapy that do not involve insulin. Choice of second and third antihyperglycemic medications may differ depending on cardiovascular comorbidities.[78][79] When 2- or 3-drug noninsulin regimens fail, basal insulin can be added. Bolus insulin can be subsequently added if needed to achieve or maintain adequate glucose control. To reduce the risk of hypoglycemia, a sulfonylurea is usually tapered if insulin is started.

Clinical properties of specific oral antihyperglycemic agents

Agents are often selected based on a discussion with the patient of the pros and cons of the agents. Agents that reduce all-cause or cardiovascular mortality may be preferred.[44]

  • Metformin can promote weight loss and may reduce cardiovascular events and mortality.[90][92]

  • SGLT2 inhibitors (canagliflozin, dapagliflozin, empagliflozin, ertugliflozin) inhibit renal glucose reabsorption. The resulting increase in glycosuria improves glycemic control, promotes weight loss, and has a diuretic effect that reduces BP.[102] There is evidence that use of SGLT2 inhibitors prevents major kidney outcomes (dialysis, transplantation, or death due to kidney disease) in people with type 2 diabetes.[103] Empagliflozin and canagliflozin have been shown to reduce cardiovascular risk in people with CVD and type 2 diabetes, and may have renal benefits.[93][104][105][94][106] Empagliflozin and canagliflozin have been shown to significantly reduce cardiovascular or all-cause mortality in those with diabetes and established CVD.[107][108][109] In one trial, treatment with dapaglifozin in patients with type 2 diabetes who had, or were at risk for, atherosclerotic CVD did not result in a lower rate of major adverse cardiovascular events, but did report a lower rate of cardiovascular death or hospitalization for heart failure.[110] Dapagliflozin also improves renal outcomes in patients with, and without, diabetes.[111] One published trial on the CVD benefits of ertugliflozin supports its use in patients with diabetes and heart failure.[112][113][114] Adverse effects for different agents have included a higher rate of genital infections, diabetic ketoacidosis, acute kidney injury, fracture, and/or amputation.[115][116][117][118]The Food and Drug Administration (FDA) and European Medicines Agency (EMA) warn of the potential increased risk of toe amputation with SGLT2 inhibitors and the need for appropriate monitoring.[119][120][121] The FDA and the UK Medicines and Healthcare products Regulatory Agency (MHRA) warn of cases of necrotizing fasciitis of the perineum (also known as Fournier gangrene) observed in post-marketing surveillance of SGLT2 inhibitors.[122][123] Thus, SGLT2 inhibitors should be avoided in patients with conditions that increase the risk for limb amputations, and in patients prone to urinary tract or genital infections.

  • GLP-1 agonists (liraglutide, exenatide, lixisenatide, semaglutide, dulaglutide) are suitable for obese patients without gastroparesis who desire weight loss, are willing to take injections, and can tolerate the common adverse effect of initial nausea.[124] As a class of drugs, GLP-1 agonist treatment has beneficial effects on cardiovascular, mortality, and kidney outcomes in patients with type 2 diabetes.[95] Liraglutide significantly reduced cardiovascular mortality and all-cause mortality in those with diabetes and CVD or high CVD risk in one randomized trial.[125] Dulaglutide and semaglutide have both been shown to reduce major cardiovascular events, but not all-cause or cardiovascular mortality.[126][127][128] Semaglutide is the only GLP-1 agonist to also be available in an oral form.[129] Exenatide and lixisenatide have both been shown not to reduce major cardiovascular events.[130] The MHRA warns of cases of diabetic ketoacidosis in patients with type 2 diabetes on a combination of a GLP-1 receptor agonist and insulin who had doses of concomitant insulin rapidly reduced or discontinued.[131]

  • DPP-4 inhibitors (sitagliptin, saxagliptin, linagliptin, alogliptin) are well tolerated, weight-neutral, but confer no mortality benefit.

  • Sulfonylureas (glipizide, glimepiride, glyburide) are the subject of long clinical experience and may reduce microvascular complications, but confer no mortality benefit and may cause weight gain and hypoglycemia.[78] Along with metformin and human insulin, these are among the more affordable antihyperglycemic medications.[132]

  • Alpha-glucosidase inhibitors (acarbose, miglitol) can be added to metformin in people with large postprandial glucose excursions, but increased flatus and gastrointestinal side effects are common. There is no strong evidence of a benefit on all-cause or cardiovascular mortality.

  • Thiazolidinediones (pioglitazone, rosiglitazone) lower blood sugar effectively but more than double the risk of congestive heart failure, often causing weight gain and edema.[78] They may cause anemia and increase fracture rates in both women and men. In addition, rosiglitazone raises low-density lipoprotein (LDL)-cholesterol and mixed evidence suggests rosiglitazone may increase the risk of cardiovascular events.[133] Rosiglitazone has been removed from the European market due to persistent safety concerns.[134] However, in 2013, the FDA lifted previous restrictions applied to rosiglitazone in the US, based on newer data.[135] As a result of an updated review, the FDA has concluded that use of pioglitazone may be linked to an increased risk of bladder cancer.[136]

  • Bromocriptine and colesevelam are oral agents approved by the FDA for glucose-lowering. They have limited impact on blood glucose in many patients. [ Cochrane Clinical Answers logo ] Bromocriptine may cause gastrointestinal side effects. Colesevelam, originally approved as a bile-acid sequestrant, requires multiple doses per day, and may bind other medications. Neither of these agents is widely used for glucose control at present.

Insulin therapy

Insulin therapy is required for severe hyperglycemia and is an option when metformin monotherapy or multidrug regimens are inadequate.[2] Because of the progressive loss of beta-cell function that characterizes the natural history of type 2 diabetes, insulin therapy is often required over time to overcome the insulin deficiency that accompanies progressive beta-cell loss in longer-standing type 2 diabetes.

Insulin treatment should be considered at the time of diagnosis if glucose level is ≥300 mg/dL or if HbA1c is ≥10%. Metformin is typically used adjunctively, in the absence of nausea, vomiting, or volume depletion. 

For individuals with severe hyperglycemia (HbA1c ≥11%; or fasting or postprandial glucose >350 mg/dL), or individuals with metabolic compromise related to hyperglycemia (polyuria, polydipsia, ongoing weight loss) but without ketonuria or dehydration, both basal (background) and bolus (mealtime/prandial) insulin are typically recommended to reverse symptoms rapidly.[78] For individuals with less dramatic hyperglycemia, insulin can often be initiated with long-acting basal insulin at bedtime.[2] Some patients' blood sugars can be well controlled with a combination of noninsulin therapy and one injection of basal insulin. However, some patients will need to use both a long-acting basal insulin (e.g., detemir, glargine, or degludec) injection once daily and rapid-acting insulin (e.g., lispro, aspart, or glulisine) injected before each meal.

Intermediate (NPH) and short-acting (regular) insulins are other choices for basal-bolus regimens. For patients with type 2 diabetes, observational studies suggest human insulins can be as effective as analog insulins for glucose control, serious hypoglycemia risk, and mortality and cardiovascular events.[137] [ Cochrane Clinical Answers logo ] Human insulins are significantly less expensive than analog insulins. For individuals with relaxed HbA1c goals, low rates of hypoglycemia, and prominent insulin resistance, as well as those with cost concerns, human insulin (NPH and regular) may be the appropriate choice of therapy.[2]

Premixed insulin is available in various ratios of rapid-acting/NPH and regular/NPH insulin combinations. When injected before (typically) breakfast and dinner meals, premixed insulin can sometimes be used effectively to cover both basal and prandial insulin needs in appropriate individuals (desire for no more than 2 injections per day, less insulin-sensitive and hypoglycemia-prone, and willing to eat consistent meals on a reasonably consistent schedule). For many, the greater flexibility and adaptability of a basal (background) and bolus (mealtime) regimen outweighs the potential convenience of premixed insulin.

Regimens should be individualized. Insulin delivery devices (insulin pens) that can be adjusted to administer set doses of insulin are widely available, and offer increased convenience and accuracy in insulin dosing. Less frequently, insulin pumps and patch pump systems are used in individuals with type 2 diabetes requiring multiple daily dose insulin. While allowing improved precision in insulin administration and dosing, insulin pump systems require significant engagement and involvement by the individuals using the systems to achieve clinical benefits beyond multiple daily dose injection-based therapy.

Metformin therapy is typically started or continued at the time of initiation of insulin in type 2 diabetes, unless contraindicated. While consideration should be given to discontinuing sulfonylurea therapy in individuals initiating insulin therapy because of additive hypoglycemia risk, other noninsulin therapies can often be continued if an individual is benefiting.[138] In particular, individuals on SGLT2 or GLP-1 therapy because of unique indications (atherosclerotic cardiovascular disease [ASCVD], heart failure, CKD) can be continued on those therapies when initiating insulin. 

Exogenous insulin is a very effective way to lower serum glucose and lower HbA1c, but its use must be guided in most patients by regular self-monitored blood glucose testing (fingerstick blood glucose testing) or continuous glucose monitoring. Hypoglycemia (glucose ≤70 mg/dL) is the most serious potential complication of insulin therapy. Another significant side effect is weight gain. Less common side effects may include hunger, nausea, diaphoresis, injection site irritation, or anaphylaxis. 

Correction doses of insulin

When basal-bolus insulin is used by motivated and knowledgeable patients, the dose of rapid-acting insulin that is administered before each meal can be based on anticipated carbohydrate content of the upcoming meal and sometimes adjusted for anticipated physical activity (carbohydrate-based dosing, sometimes called “carb-counting”), rather than administered as a fixed mealtime dose. Correctional doses of rapid-acting insulin can also be applied based on premeal blood sugar readings (correctional algorithms). One acceptable method of determining a correction algorithm is to divide 1800 by the total daily dose of insulin to yield the expected blood sugar reduction per unit of insulin. For example, for a patient taking 60 units of insulin per day, the expected blood sugar lowering of 1 additional unit of insulin would be 1800/60=30 mg/dL.

Cardiovascular risk management

Blood pressure

Blood pressure (BP) guidelines differ regarding recommended targets for those with diabetes.

  • The 2017 American College of Cardiology (ACC)/American Heart Association (AHA) guideline for management of high BP in adults recommends BP <130/80 mmHg for people with diabetes, and classifies BP using the following categories:[69]

    • normal (<120/80 mmHg)

    • elevated (120-129/<80 mmHg)

    • stage 1 (130-139/80-89 mmHg)

    • stage 2 hypertension (≥140/90 mmHg).

  • The American Diabetes Association (ADA) Standards of Medical Care in Diabetes recommends goal BP <140/90 mmHg for people with diabetes, with consideration of a goal BP <130/80 mmHg for those with established hypertension and diabetes and who have established CVD or 10-year cardiovascular risk greater than 15%.[2][139]

  • Regardless of specific BP goal, initial treatment with an ACE inhibitor, an angiotensin-II receptor antagonist, a calcium-channel blocker, or a thiazide (or thiazide-like) diuretic is preferred. Black people may benefit most from a thiazide diuretic or a calcium-channel blocker.[139] ACE inhibitors may reduce mortality and cardiovascular events more than angiotensin-II receptor antagonists.[77] Combination drug therapy (with ACE inhibitor/angiotensin-II receptor antagonist, calcium-channel blocker, thiazide diuretic) is often required to reach BP goals. Combined use of an ACE inhibitor and an angiotensin-II receptor antagonist is not recommended due to increased risk of adverse events.[140] However, most people with chronic kidney disease (CKD) should receive an ACE inhibitor or an angiotensin-II receptor antagonist as part of their antihypertensive regimen.[139] CKD is defined as (a) age <70 years with glomerular filtration rate (GFR) <60 mL/minute/1.73 m², or (b) people of any age with albuminuria >30 mg albumin/g of creatinine at any level of GFR.

  • Consider initiation and titration of two antihypertensive medications along with lifestyle therapy if BP ≥160/100 mmHg.[2]

  • Beta-blockers are not contraindicated in people with diabetes but are less-preferred antihypertensive agents[139] and may mask symptoms of hypoglycemia. 

  • If BP remains uncontrolled on first-line therapies, discontinue or minimize interfering substances such as nonsteroidal anti-inflammatory drugs (NSAIDs), evaluate for secondary causes of hypertension (including obstructive sleep apnea), and consider the addition of a mineralocorticoid receptor agonist,[141] and/or refer to a hypertension specialist.

  • BP goals and guidelines are evolving as more studies are carried out. The Systolic Blood Pressure Intervention Trial (SPRINT) was terminated early, as it found that a lower systolic target of 120 mmHg reduced cardiovascular complications and deaths in people over age 50 years with high BP and at least one additional risk factor for heart disease.[142] However, people with diabetes were excluded from this trial.

  • There is an increasing emphasis to incorporate the use of home BP monitoring into the diagnosis and management of hypertension in adults, including those with diabetes.[143]

Lipids

  • The ACC/AHA guidelines recommend high-intensity statin therapy if tolerated in adults aged over 21 years if the patient has clinical ASCVD or LDL-cholesterol ≥190 mg/dL.[68] In those ages 40 to 75 years with diabetes but no ASCVD, moderate-intensity statin therapy should be considered. [ Cochrane Clinical Answers logo ] In those with diabetes and 10-year ACC/AHA cardiovascular risk greater than 20%, consider adding ezetimibe to maximally-tolerated statin therapy to reduce LDL by 50% or more.[68] In diabetes patients over age 75 years, it is reasonable to consider and discuss with the patient advantages and disadvantages of initiation or continuation of statin therapy.[68] In those ages 20 to 39 years with diabetes, it may be reasonable to initiate statin therapy in the presence of albuminuria, estimated GFR <60 mL/minute/1.73 m², retinopathy, or neuropathy.[68] Statins are contraindicated in pregnancy.

  • The ADA recommends that management of lipid abnormalities is driven by risk status rather than LDL cholesterol level.[2] Risk factors for CVD include LDL-cholesterol >100 mg/dL, high BP, smoking, and overweight and obesity. Lifestyle therapy is recommended for all people. For people with diabetes and overt CVD, high-intensity statin therapy is added to lifestyle therapy, regardless of baseline lipid values. High-intensity statin therapy is also considered for those over age 40 years without overt CVD, but with one or more CVD risk factors. For people with diabetes over age 40 years without additional CVD risk factors, moderate-intensity statin therapy is still considered. For some people with diabetes and established coronary heart disease who have persistently elevated LDL despite maximally-tolerated statin therapy, addition of ezetimibe or a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor (e.g., alirocumab, evolocumab) may confer clinical benefit.[2][144][145][146]

  • In individuals with established CVD, or high cardiovascular risk on a statin with controlled LDL cholesterol but elevated triglycerides, the addition of icosapent ethyl has been shown to modestly reduce cardiovascular events.[2][147]

Smoking cessation

  • Patients who smoke should be provided with smoking cessation resources, and be provided with smoking cessation assistance such as medications and counseling as appropriate. Varenicline combined with nicotine replacement therapy may be more effective than varenicline alone.[148] The ADA does not support e-cigarettes as an alternative to smoking or to facilitate smoking cessation.[2]

Antiplatelet therapy

  • Adults with CVD should receive aspirin for secondary prevention. Clopidogrel is an alternative for patients with aspirin allergy or intolerance. Dual antiplatelet therapy is reasonable for up to 12 months after an acute coronary syndrome. The main adverse effect is an increased risk of gastrointestinal bleeding.[2][149]

  • The ADA recommends that aspirin therapy be considered for primary prevention in adults with type 2 diabetes ages 50 to 70 years who are at increased cardiovascular risk (family history of premature CVD, hypertension, dyslipidemias, smoking, CKD/albuminuria), unless they are at high risk of serious bleeding.[2]

  • For patients aged over 70 years, the risk of bleeding increases and aspirin is generally not recommended for primary prevention in this population.[150]

  • US Preventive Services Task Force (USPSTF) recommendations for primary prevention of heart attack or stroke in those ages 50 to 70 years are similar.[151]

Bariatric surgery for treatment of diabetes in patients with obesity

Randomized clinical trials have shown a benefit from bariatric surgery (also referred to as metabolic surgery) with regard to diabetes remission, glycemic control, need for glucose-lowering medications, quality of life, and reduction in cardiovascular risk factor markers over the short term (e.g., 1-3 years) in people with type 2 diabetes compared with medical therapy alone,[152][153][154][155][156] as well as for possible prevention of type 2 diabetes.[157] Cohort studies suggest that both Roux en Y bypass and sleeve gastrectomy procedures lead to diabetes remission that lasts a mean of about 5 years in more than half of patients, and significantly reduce mortality, stroke, myocardial infarction, and microvascular complications in those with type 2 diabetes.[158][159][160] Compared with sleeve gastrectomy, Roux en Y leads to somewhat greater weight loss and other benefits, but is a more technically challenging operation with higher reoperation and readmission rates, and more of a tendency to malabsorption of vitamins and minerals postoperatively. The benefits and risks of bariatric surgery also vary substantially across type 2 diabetes patient subgroups. In observational studies, average benefits appeared to be highest in those who are younger (age 40-50 years), those with more recent onset of type 2 diabetes, and those not on insulin therapy.[161]

Health insurers in the US generally restrict payment for bariatric surgery, but the eligibility criteria have been slowly expanding over time. Bariatric surgery may be considered for adults with BMI ≥40 kg/m² (≥37.5 kg/m² for Asian-Americans) with any level of glycemic control/any complexity of glucose-lowering regimen.[2] Surgery may also be considered for adults with BMI 35.0 to 39.9 kg/m² (32.5 to 37.4 kg/m² for Asian-Americans) with hyperglycemia inadequately controlled despite lifestyle and optimal medical management, and may be considered for those with BMI 30.0 to 34.9 kg/m² (27.5 to 32.4 kg/m² for Asian-Americans) with hyperglycemia inadequately controlled despite optimal use of oral or injectable medications (including insulin).[2] Bariatric surgery is best done in a high-volume, specialized center.[2]

Treatment of diabetes in pregnancy

Good glucose control with HbA1c as close to normal as is safely possible (ideally HbA1c <6.5% [48 mmol/mol]) before conception and during pregnancy optimizes maternal and fetal health outcomes.[2][162] American Diabetes Association guidelines recommend the following blood glucose targets in pregnant women with preexisting type 2 diabetes (the same as for gestational diabetes): <95 mg/dL fasting, and either ≤140 mg/dL 1-hour postprandially or ≤120 mg/dL 2-hour postprandially, with HbA1c goal individualized between <6% and <6.5% or up to <7% as necessary to prevent hypoglycemia.[2]

In clinical practice, insulin is usually used when nutrition therapy fails to achieve these goals. NPH insulin may be combined with human short-acting or analog rapid-acting insulin. Long-acting analog insulins (glargine, detemir, or degludec) are not FDA-approved in pregnancy. ACE inhibitors, angiotensin-II receptor antagonists, and beta-blockers are not recommended in pregnancy and should be avoided. Statins are contraindicated in pregnancy. Retinal exam in those with diabetes prior to pregnancy should be performed prior to, during, and after pregnancy. Women with diabetes who anticipate pregnancy or who are pregnant benefit from care supervision by a specialized center whenever possible.

Care delivery models

Diabetes care in the US has, on average, dramatically improved in the past 20 years, with a 50% reduction in mortality rates, cardiovascular mortality rates, and cardiovascular event rates in adults with diabetes.[20] Many factors have contributed to diabetes care improvement and better clinical outcomes for patients.[163] The principal model used to frame these strategies is the Chronic Care Model.[164] The model includes 6 core elements: delivery system design, self-management support, decision support, clinical information systems, community resources and policies, and health systems.

Evidence is generally supportive of the following care improvement strategies.

  • A multidisciplinary team approach to patient care, including the involvement of trained diabetes self-management educators, pharmacists, and case managers[165][166]

  • Advanced and integrated electronic medical record clinical decision support beyond simple reminder systems and alerts[167][168]

  • Simulated case-based learning interventions for clinicians.[169][170][171]

Other redesigns to the care delivery system such as alternative reimbursement methods, public policy changes to support healthier lifestyles, the patient-centered medical home, and mobile health (mHealth) technology may provide additional opportunities to improve care and are currently being evaluated.[172][173] Diabetes management decisions should be timely, rely on evidence-based guidelines, and be made collaboratively with the patient.

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