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COMMONLY ASSOCIATED CONDITIONS
- Obesity (abdominal and visceral obesity)
- Dyslipidemia with high triglycerides (TG)
- Metabolic syndrome
- PCOS
- GDM
- Low HDL
- HTN
- Congenital diseases (Down, Turner, Klinefelter, and Wolfram syndromes)
DIAGNOSIS
Who to screen
- BMI ≥25
- Age >45 years
- First-degree relative with diabetes
- Low HDL <35 mg/dL
- High TG >250 mg/dL
- HTN: BP >140/90 mm Hg or on treatment
- Hx of GDM
- Physical inactivity
- Hx of cardiovascular disease
- Ethnic group at increased risk (non-Hispanic black, Native American, Hispanics, Asian American, Pacific Islander)
- HgbA1c ≥5.7%, IGT, or IFG on previous testing
- PCOS
- Conditions associated with insulin resistance such as severe obesity or acanthosis nigricans
HISTORY
- No clear symptoms
- Polyuria
- Polydipsia
- Weight loss
- Blurred vision
- Polyphagia
PHYSICAL EXAM
- General physical exam
- BMI assessment
DIFFERENTIAL DIAGNOSIS
- Type A insulin resistance
- Leprechaunism
- Rabson-Mendenhall syndrome
- Lipoatrophic diabetes
- Pancreatitis
- Cystic fibrosis
- Hemochromatosis
- Acromegaly
- Cushing syndrome
- Glucagonoma
- Pheochromocytoma
- Hyperthyroidism
- Somatostatinoma
- Aldosteronoma
- Drug-induced hyperglycemia
- Thiazide diuretics (high doses)
- β-blockers
- Corticosteroids (including inhaled corticosteroids)
- Thyroid hormone
- α-Interferon
- Pentamidine
- Protease inhibitors
- Atypical antipsychotics
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
- Fasting glucose
- 2-Hour OGTT
- HbA1c
- Repeat screen at least at 3-year intervals with normal results or sooner depending on risk status (5).
Follow-Up Tests & Special Considerations
- Fasting lipid profile
- Creatinine and GFR
- Urinalysis
- Microalbumin-to-creatinine ratio
- Thyroid-stimulating hormone with free T4
TREATMENT
- Lifestyle aimed at increasing physical activity and weight loss prevents or delays the development of diabetes in people with IGT and IFG (6)[C].
- Exercise and lifestyle:
- At least 150 minute/week of moderate-intensity aerobic exercise and/or at least 90 minute/week of vigorous aerobic exercise
- Resistance exercise improves insulin sensitivity to the same extent as aerobic exercise; resistance training 3 times per week is recommended for those with type 2 diabetes
- Smoking cessation
- Follow-up counseling (6)[B]
- Diabetes prevention programs are cost effective (6)[B].
- Diabetes prevention program (participants <60 years of age, BMI ≥35 kg/m2, women with a history of gestational diabetes) showed that loss of weight through diet and exercise reduces risk of developing diabetes by 58% and demonstrated that lifestyle modification decreases risk of diabetes more than metformin.
- Because of its effectiveness, low cost, and long-term safety, the ADA recommends consideration of metformin for prevention of diabetes in individuals with IGT [A], IFG [C], or an A1c 5.7-6.4% [C], especially for those with BMI >35kg/m2, aged <60 years, and women with history of GDM [A].
- Dietary recommendations:
- Either low-carbohydrate, low-fat calorie-restricted, or Mediterranean diets may be effective.
- Diets high in fiber-rich foods, such as vegetables, fruits, whole grains, seeds, and nuts plus white meat sources are protective against type 2 diabetes (7).
- Restrict beverages containing simple sugars, as they increase risk of diabetes (7).
- Intake of polyunsaturated fatty acid (PUFA) may improve glycemic control; however, data is inconsistent regarding PUFA and other types of fatty acids (7).
- Individuals who have prediabetes or diabetes should receive individualized medical nutrition therapy (MNT) as needed to achieve treatment goals, preferably provided by a registered dietitian familiar with the components of diabetes MNT (6).
MEDICATION
First Line
Metformin (drug of choice) 500 mg BID or 850 mg daily may reduce incidence of new-onset diabetes and BMI (level 2); contraindicated with Cr >1.5 in males and >1.4 in females increases risk of lactic acidosis (6).
Second Line
Acarbose: started as 50 mg PO once daily and titrated to 100 mg PO TID, may reduce incidence of diabetes; GI upset is common (7).
ISSUES FOR REFERRAL
- Nutritionist
- Diabetes educator/registered dietitian upon diagnosis
- Exercise physiologist
- Lifestyle coaching
ADDITIONAL THERAPIES
- Weight loss of 5-10% improves glycemic control, increases insulin sensitivity, improves lipids, and lowers BP.
- Alternative/botanical therapy:
- Fenugreek, bitter melon, and cinnamon have reduced hyperglycemia and improved insulin sensitivity in studies by Deng(8) and Graf et al. (9).
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
- Consider self-monitoring of blood glucose.
- At least annual monitoring for development of diabetes with HbA1c, 2-hour OGTT, or fasting glucose
- BP should be routinely measured.
- Annual testing for lipid abnormalities and microalbuminuria (for detection and therapy modification of incipient diabetic nephropathy)
DIET
- Monitor carbohydrate intake.
- Macronutrient distribution should be based on individual assessment of eating patterns, preferences, and metabolic goals.
- Consider Mediterranean diet.
- Maximize low glycemic index foods.
- Low-fat (<25%) intake: Saturated fat intake should be <7% of total calories.
- Minimize trans fat intake.
- Low-sodium intake <2,300 mg/day
- High-fiber (~50 g/day; 14 g/1,000 kcal) and whole-grain intake
- Drink ample quantities of water, minimum of 64 oz of water daily, and strictly avoid sugar-sweetened beverages.
- Moderate alcohol intake: 1 drink/day for women; 2 drinks/day for men
PROGNOSIS
- Individuals with IFG and/or IGT have high risk for the future development of diabetes.
- Prediabetes increases the risk of developing type 2 diabetes, heart disease, and stroke.
- The potential impact of interventions to reduce mortality or the incidence of cardiovascular disease has not been demonstrated to date.
- 20-70% of individuals with prediabetes who do not lose weight, change their dietary habits, and/or engage in moderate physical activity will progress to type 2 diabetes within 3 to 6 years (7).
- HbA1c >6.5% at age 12 to 39 years associated with increased risk of death before age 55 years compared with HbA1c <5.7%
COMPLICATIONS
- Cardiovascular disease
- PAD
- Stroke: 2 to 4 times higher risk
- Ketoacidosis
- Sexual dysfunction
- Gastroparesis
- Nephropathy and potential for renal failure
- Retinopathy and potential for loss of vision
- Peripheral and autonomic neuropathy
REFERENCES
11 Nathan DM, Davidson MB, DeFronzo RA, et al. Impaired fasting glucose and impaired glucose tolerance: implications for care. Diabetes Care. 2007;30(3):753-759.22 Centers for Disease Control and Prevention. National Diabetes Statistics Report: Estimates of Diabetes and Its Burden in the United States, 2014. Atlanta, GA: U.S. Department of Health and Human Services; 2014.33 Centers for Disease Control and Prevention. Awareness of prediabetes-United States, 2005-2010. MMWR Morb Mortal Weekly Rep. 2013:62(11): 209-212.44 Centers for Disease Control and Prevention. Prediabetes facts. http://www.cdc.gov/diabetes/basics/prediabetes.html. Accessed 2014.55 American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. 2014;37(Suppl 1):S81-S90.66 American Diabetes Association. Standards of medical care in diabetes-2014. Diabetes Care. 2014;37(Suppl 1):S14-S80.77 Stull AJ. Lifestyle approaches and glucose intolerance [published online ahead of print October 14, 2014]. Am J Lifestyle Med. 2014. http://doi: 10.1177/1559827614554186.88 Deng R. A review of the hypoglycemia effects of five commonly used herbal food supplements. Recent Pat Food Nutr Agric. 2012;4(1):50-60.99 Graf BL, Raskin I, Cefalu WT, et al. Plant-derived therapeutics for the treatment of metabolic syndrome. Curr Opin Investig Drugs. 2010;11(10):1107-1115.
ADDITIONAL READING
- Maruthur NM, Ma Y, Delahanty LM, et al. Early response to preventive strategies in the Diabetes Prevention Program. J Gen Intern Med. 2013;28(12):1629-1636.
- Ramachandran A, Riddle MC, Kabali C, et al. Relationship between A1C and fasting plasma glucose in dysglycemia or type 2 diabetes: an analysis of baseline data from the ORIGIN trial. Diabetes Care. 2012;35(4):749-753.
CODES
ICD10
- E74.39 Other disorders of intestinal carbohydrate absorption
- R73.09 Other abnormal glucose
- R73.01 Impaired fasting glucose
- R73.02 Impaired glucose tolerance (oral)
ICD9
- 271.3 Intestinal disaccharidase deficiencies and disaccharide malabsorption
- 790.29 Other abnormal glucose
- 790.21 Impaired fasting glucose
- 790.22 Impaired glucose tolerance test (oral)
SNOMED
- 9414007 Impaired glucose tolerance (disorder)
- 102660008 Abnormal glucose level
- 390951007 Impaired fasting glycaemia
CLINICAL PEARLS
- Lifestyle optimization is essential for all patients with prediabetes.
- Research shows that you can lower your risk for type 2 diabetes by 58% by losing 7% of your body weight (or 15 lb if you weigh 200 lb).
- Exercising moderately (such as brisk walking) 30 minutes/day, 5 days a week
- Consider concurrent cardiovascular risks and further workup as indicated clinically.
- Patient education and lifestyle reinforcement should be emphasized in all clinical encounters.