UpToDate
Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate®

Clinical presentation and diagnosis of diabetes mellitus in adults

Author
David K McCulloch, MD
Section Editors
David M Nathan, MD
Joseph I Wolfsdorf, MB, BCh
Deputy Editor
Jean E Mulder, MD

INTRODUCTION

The term diabetes mellitus describes several diseases of abnormal carbohydrate metabolism that are characterized by hyperglycemia. It is associated with a relative or absolute impairment in insulin secretion, along with varying degrees of peripheral resistance to the action of insulin. Every few years, the diabetes community reevaluates the current recommendations for the classification, diagnosis, and screening of diabetes, reflecting new information from research and clinical practice.

The American Diabetes Association (ADA) issued diagnostic criteria for diabetes mellitus in 1997, with follow-up in 2003 and 2010 [1-3]. The diagnosis is based on one of four abnormalities: glycated hemoglobin (A1C), fasting plasma glucose (FPG), random elevated glucose with symptoms, or abnormal oral glucose tolerance test (OGTT) (table 1). Patients with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) are referred to as having increased risk for diabetes or prediabetes. (See 'Diagnostic criteria' below.)

Screening for and prevention of diabetes is reviewed elsewhere. The etiologic classification of diabetes mellitus is also discussed separately. (See "Screening for type 2 diabetes mellitus" and "Prevention of type 2 diabetes mellitus" and "Prevention of type 1 diabetes mellitus" and "Classification of diabetes mellitus and genetic diabetic syndromes".)

CLINICAL PRESENTATION

Type 2 diabetes is by far the most common type of diabetes in adults (>90 percent) and is characterized by hyperglycemia and variable degrees of insulin deficiency and resistance. The majority of patients are asymptomatic, and hyperglycemia is noted on routine laboratory evaluation, prompting further testing. The frequency of symptomatic diabetes has been decreasing in parallel with improved efforts to diagnose diabetes earlier through screening (see "Screening for type 2 diabetes mellitus"). Classic symptoms of hyperglycemia include polyuria, polydipsia, nocturia, blurred vision, and, infrequently, weight loss. These symptoms are often noted only in retrospect after a blood glucose value has been shown to be elevated. Polyuria occurs when the serum glucose concentration rises significantly above 180 mg/dL (10 mmol/L), exceeding the renal threshold for glucose, which leads to increased urinary glucose excretion. Glycosuria causes osmotic diuresis (ie, polyuria) and hypovolemia, which in turn can lead to polydipsia. Patients who replete their volume losses with concentrated sugar drinks, such as non-diet sodas, exacerbate their hyperglycemia and osmotic diuresis.

Rarely adults with type 2 diabetes can present with a hyperosmolar hyperglycemic state, characterized by marked hyperglycemia without ketoacidosis, severe dehydration, and obtundation. Diabetic ketoacidosis (DKA) as the presenting symptom of type 2 diabetes is also uncommon in adults but may occur under certain circumstances (usually severe infection or other illness) and in non-Caucasian ethnic groups. (See "Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Clinical features, evaluation, and diagnosis" and "Syndromes of ketosis-prone diabetes mellitus".)

             

Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Feb 2017. | This topic last updated: Fri Jan 20 00:00:00 GMT+00:00 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
References
Top
  1. Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care 1997; 20:1183.
  2. Genuth S, Alberti KG, Bennett P, et al. Follow-up report on the diagnosis of diabetes mellitus. Diabetes Care 2003; 26:3160.
  3. American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care 2010; 33 Suppl 1:S62.
  4. Merger SR, Leslie RD, Boehm BO. The broad clinical phenotype of Type 1 diabetes at presentation. Diabet Med 2013; 30:170.
  5. Karjalainen J, Salmela P, Ilonen J, et al. A comparison of childhood and adult type I diabetes mellitus. N Engl J Med 1989; 320:881.
  6. American Diabetes Association. 2. Classification and Diagnosis of Diabetes. Diabetes Care 2017; 40:S11.
  7. Selvin E, Crainiceanu CM, Brancati FL, Coresh J. Short-term variability in measures of glycemia and implications for the classification of diabetes. Arch Intern Med 2007; 167:1545.
  8. Carson AP, Reynolds K, Fonseca VA, Muntner P. Comparison of A1C and fasting glucose criteria to diagnose diabetes among U.S. adults. Diabetes Care 2010; 33:95.
  9. Cowie CC, Rust KF, Byrd-Holt DD, et al. Prevalence of diabetes and high risk for diabetes using A1C criteria in the U.S. population in 1988-2006. Diabetes Care 2010; 33:562.
  10. Malkani S, Mordes JP. Implications of using hemoglobin A1C for diagnosing diabetes mellitus. Am J Med 2011; 124:395.
  11. http://www.who.int/diabetes/publications/report-hba1c_2011.pdf (Accessed on June 07, 2011).
  12. http://whqlibdoc.who.int/publications/2006/9241594934_eng.pdf (Accessed on December 22, 2011).
  13. International Expert Committee. International Expert Committee report on the role of the A1C assay in the diagnosis of diabetes. Diabetes Care 2009; 32:1327.
  14. Nathan DM, Davidson MB, DeFronzo RA, et al. Impaired fasting glucose and impaired glucose tolerance: implications for care. Diabetes Care 2007; 30:753.
  15. Chiang JL, Kirkman MS, Laffel LM, et al. Type 1 diabetes through the life span: a position statement of the American Diabetes Association. Diabetes Care 2014; 37:2034.
  16. Peters AL, Davidson MB, Schriger DL, Hasselblad V. A clinical approach for the diagnosis of diabetes mellitus: an analysis using glycosylated hemoglobin levels. Meta-analysis Research Group on the Diagnosis of Diabetes Using Glycated Hemoglobin Levels. JAMA 1996; 276:1246.
  17. Rohlfing CL, Little RR, Wiedmeyer HM, et al. Use of GHb (HbA1c) in screening for undiagnosed diabetes in the U.S. population. Diabetes Care 2000; 23:187.
  18. Buell C, Kermah D, Davidson MB. Utility of A1C for diabetes screening in the 1999 2004 NHANES population. Diabetes Care 2007; 30:2233.
  19. Bennett CM, Guo M, Dharmage SC. HbA(1c) as a screening tool for detection of Type 2 diabetes: a systematic review. Diabet Med 2007; 24:333.
  20. Nathan DM, Kuenen J, Borg R, et al. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008; 31:1473.
  21. Sabanayagam C, Liew G, Tai ES, et al. Relationship between glycated haemoglobin and microvascular complications: is there a natural cut-off point for the diagnosis of diabetes? Diabetologia 2009; 52:1279.
  22. Miyazaki M, Kubo M, Kiyohara Y, et al. Comparison of diagnostic methods for diabetes mellitus based on prevalence of retinopathy in a Japanese population: the Hisayama Study. Diabetologia 2004; 47:1411.
  23. Massin P, Lange C, Tichet J, et al. Hemoglobin A1c and fasting plasma glucose levels as predictors of retinopathy at 10 years: the French DESIR study. Arch Ophthalmol 2011; 129:188.
  24. Cheng YJ, Gregg EW, Geiss LS, et al. Association of A1C and fasting plasma glucose levels with diabetic retinopathy prevalence in the U.S. population: Implications for diabetes diagnostic thresholds. Diabetes Care 2009; 32:2027.
  25. Ashraf H, Boroumand MA, Amirzadegan A, et al. Hemoglobin A1C in non-diabetic patients: an independent predictor of coronary artery disease and its severity. Diabetes Res Clin Pract 2013; 102:225.
  26. Huang Y, Cai X, Mai W, et al. Association between prediabetes and risk of cardiovascular disease and all cause mortality: systematic review and meta-analysis. BMJ 2016; 355:i5953.
  27. Emerging Risk Factors Collaboration, Di Angelantonio E, Gao P, et al. Glycated hemoglobin measurement and prediction of cardiovascular disease. JAMA 2014; 311:1225.
  28. Ishihara M, Inoue I, Kawagoe T, et al. Is admission hyperglycaemia in non-diabetic patients with acute myocardial infarction a surrogate for previously undiagnosed abnormal glucose tolerance? Eur Heart J 2006; 27:2413.
  29. McAllister DA, Hughes KA, Lone N, et al. Stress hyperglycaemia in hospitalised patients and their 3-year risk of diabetes: a Scottish retrospective cohort study. PLoS Med 2014; 11:e1001708.
  30. MacIntyre EJ, Majumdar SR, Gamble JM, et al. Stress hyperglycemia and newly diagnosed diabetes in 2124 patients hospitalized with pneumonia. Am J Med 2012; 125:1036.e17.