Type 2 diabetes mellitus in adults

Last reviewed: March 2019

Last updated: July 2018

Summary

The cornerstone of therapy for all patients with diabetes is a personalized self-management program, usually developed with the patient by a diabetes education nurse or nutritionist.

Lifestyle changes plus metformin are initial antihyperglycemic therapy for most patients. Glycemic goals and treatment choices are individualized.

Blood pressure control, lipid management, smoking cessation, and glycemic management reduce the risk of macrovascular complications such as heart attack and stroke. Glycemic control and blood pressure management reduce the risk of microvascular complications (neuropathy, nephropathy, retinopathy).

Selected glucose-lowering drugs reduce all-cause and cardiovascular mortality.

Definition

Type 2 diabetes mellitus is a progressive disorder defined by deficits in insulin secretion and action that lead to abnormal glucose metabolism and related metabolic derangements. [1] Although the etiologies of type 1 and type 2 diabetes differ dramatically, both lead to hyperglycemic states, and both share common macrovascular (coronary heart, cerebrovascular, and peripheral vascular disease) and microvascular (retinopathy, nephropathy, and neuropathy) complications. Type 2 diabetes is most often diagnosed following routine screening. It is preceded by a state of prediabetes, which is defined by a single fasting plasma glucose of 100-125 mg/dL or an HbA1c of 5.7% to 6.4% in the absence of diabetes. Diabetes diagnosis is based on 2 confirmed values of: fasting plasma glucose >125 mg/dL; HbA1c of 6.5% or greater; or (less commonly) glucose tolerance test results, or a random plasma glucose of ≥200 mg/dL plus symptoms of hyperglycemia. [2]

History and exam

Key diagnostic factors

asymptomatic
candidal infections
skin infections
urinary tract infections

Full details

Other diagnostic factors

fatigue
blurred vision
polydipsia
polyphagia
polyuria
paresthesias
nocturia
unintentional weight loss
acanthosis nigricans

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Risk factors

older age
overweight/obesity
gestational diabetes
prediabetes
family history of type 2 diabetes
African, Hispanic, or American-Indian ancestry
physical inactivity
polycystic ovary syndrome
hypertension
dyslipidemia
cardiovascular disease

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Diagnostic investigations

1st investigations to order

HbA1c
fasting plasma glucose
random plasma glucose
2-hour post-load glucose after 75 g oral glucose

Full details

Investigations to consider

fasting lipid profile
urine ketones
random C-peptide
urinary albumin excretion
serum creatinine and estimated GFR
ECG
ankle-brachial index (ABI)
dilated retinal examination

Full details

Treatment algorithm

INITIAL

nonpregnant: at diagnosis

ACUTE

marked hyperglycemia nonpregnant: serum glucose ≥300 mg/dL or HbA1c ≥10% or symptomatic

without marked hyperglycemia nonpregnant asymptomatic: serum glucose <300 mg/dL or HbA1c <10%

pregnant

Contributors

Authors VIEW ALL 

Patrick J. O'Connor, MD, MPH

Senior Clinical Investigator

HealthPartners Research Foundation

Minneapolis

Disclosures

PJO receives research funding from the National Institutes of Health on multiple projects, and in the past several years has received funds for travel for consulting or grand rounds at Mayo Clinic, Peking University, and University of Vienna. PJO is an author of a number of references cited in this monograph.

JoAnn M. Sperl-Hillen, MD

Senior Clinical Investigator

HealthPartners Research Foundation

Minneapolis

Disclosures

JMS-H is an author of a number of references cited in this monograph. She is an inventor on a US patent for Disease Treatment Simulation, a simulation-based technology developed without commercial support to educate health providers on chronic disease management in a virtual environment. She serves as a non-paid member of the board of directors for SimCare Health, a company that has an exclusive license agreement for educational software developed using the simulation technology.

Peer reviewers VIEW ALL 

David K. McCulloch, MD

Medical Director

Clinical Improvement Group Health Cooperative

Seattle

Disclosures

DKM declares that he has no competing interests.

Ashim K. Sinha, MBBS, MD, FRACP, FACE

Associate Professor

Director of Diabetes and Endocrinology

Cairns Base Hospital and Diabetes Centre

Queensland

Australia

Disclosures

AKS declares that he has no competing interests.

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Type 2 diabetes mellitus in adults

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

nonpregnant: at diagnosis

marked hyperglycemia nonpregnant: serum glucose ≥300 mg/dL or HbA1c ≥10% or symptomatic

without marked hyperglycemia nonpregnant asymptomatic: serum glucose <300 mg/dL or HbA1c <10%

pregnant

Contributors

Authors VIEW ALL 

Patrick J. O'Connor, MD, MPH

Disclosures

JoAnn M. Sperl-Hillen, MD

Disclosures

Peer reviewers VIEW ALL 

David K. McCulloch, MD

Disclosures

Ashim K. Sinha, MBBS, MD, FRACP, FACE

Disclosures

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