Recommendations for Distinguishing Between Type 1 and Type 2 Diabetes
Consider a diagnosis of type 1 diabetes or one of its variants in AI/AN patients of any age or weight who present with a new onset of diabetes and an unclear clinical picture.
Obtain laboratory studies and exams as needed to aid in diabetes classification.
As diabetes science has progressed and as more children are being diagnosed with diabetes, it has become clear that type 1 and type 2 diabetes are at either end of a continuum that includes autoimmune-mediated insulin deficiency and insulin resistance. While providers easily recognize patients with classic type 1 or type 2 diabetes, there are a fair number of patients whose clinical presentation does not lend itself to such classification.
Making the distinction between type 1 and type 2 diabetes is important because it will dictate the immediate and long-term need for insulin treatment. For example, in patients with type 2 diabetes who also have one or more positive antibodies, there will be a shorter timeframe until insulin will be required – for glycemic control, if not for preventing ketosis. In patients with the type 1 variant known as Latent Autoimmune Diabetes of Adults (LADA), insulin may not be required initially, but over time they will progress to requiring insulin to avoid ketosis.
While the vast majority of AI/AN patients with diabetes have type 2, type 1 diabetes and its variants do occur in AI/AN patients, particularly those of mixed heritage. Type 1 diabetes must be considered in patients of any age or weight who present with a new onset of diabetes and an unclear clinical picture. This is especially true in children, even if they are overweight.
Although no test can distinguish definitively between type 1 and type 2 diabetes, several laboratory studies may be helpful when the diagnosis is not clinically clear. Providers should consider obtaining consultation if they are unfamiliar with the use of these tests or how to make a diagnosis in a complex patient.
Measurement of Endogenous Insulin Secretion
The results for tests to measure endogenous insulin secretion may be low in type 2 diabetes patients with glucose toxicity. If in doubt, measure the following after glycemic control has been restored for several weeks:
Fasting insulin level – if the patient is not on exogenous insulin
C-peptide (the other half of pro-insulin) – this is useful even if the patient is taking insulin injections.
Positive antibody tests denote an autoimmune process, but negative tests do not rule it out:
IA-2 (Insulinoma-associated protein-2)
GAD-65 (Glutamic acid decarboxylate-65)
Other antibody tests have been used in research and clinical settings – e.g., ZnT8 (Zinc Transporter 8), thyroid peroxidase antibodies, insulin autoantibodies, etc.
Other Lab Tests and Exams
Although some overweight type 1 diabetes patients may have some signs of insulin resistance, in general, they will not have the usual type 2 diabetes measurements at diagnosis. Gauging the degree of insulin deficiency versus insulin resistance with the following tests can be helpful:
Lipids – Type 2 diabetes patients have the typical low HDL/high triglyceride pattern.
Blood pressure – Type 2 diabetes patients often have some degree of hypertension at time of diabetes diagnosis.
Ketones – Although patients with type 2 diabetes can present with ketonuria and even diabetic ketoacidosis (DKA), generally these only occur at very high glucose levels or with a serious concurrent illness or infection. More often, it is patients with type 1 diabetes who present with significant ketosis and who are more profoundly acidotic with DKA.
Microvascular complications – Many type 2 diabetes patients already have some degree of retinopathy, microalbuminuria, or neuropathy at the time of diabetes diagnosis. This is seldom true of patients with type 1 diabetes.
Weight loss – The degree and speed of weight loss before diagnosis is usually more rapid in patients with type 1 diabetes than with type 2 diabetes.
Even taking the results of these tests into consideration, there still will be a few patients whose type of new-onset diabetes is not initially clear; over time, however, the diagnosis will become apparent. In the meantime, if there is concern that the patient may become acidotic if taken off insulin or if insulin is needed for glycemic control, insulin therapy should be continued, at least until it is established that it is no longer necessary.
Beginning at puberty, discuss sexual activity, the need for pregnancy prevention or planning, and contraception as part of routine diabetes care for women.
Providers need to assess each woman’s situation:
Women with diabetes should be considered for contraception, preferably a form that is long-acting such as an IUD or Contraceptive Implant since these methods have much lower failure rates.
For women not on a long-acting form of contraception, consider prescribing only those diabetes-related medications that are safe in the event of an unplanned pregnancy.
Discuss with patients the increased risk of pregnancy with medications such as metformin and TZDs that may increase fertility:
Offer contraception when starting these medications.
Optimally, pregnancies in women with diabetes of all ages are planned for, including achieving preconception glycemic control and switching to medications that are safe to use in pregnancy. While this goal is not always achieved in adult women, it is even less likely to occur in adolescent girls. Hyperglycemia, as well as certain diabetes-related medications (e.g., statins, ACE inhibitors, ARBs), are potentially toxic to the developing fetus. As such, providers need to be proactive in regard to contraception and to anticipate the possibility of unplanned pregnancies. Women with diabetes often have comorbid issues that affect the selection of an optimal contraceptive method. An excellent tool to aid in this decision is the U.S. Medical Eligibility Criteria for Contraceptive Use (USMEC).
Precontraception, Pregnancy, and Postpartum Diabetes Testing and Care
As diabetes incidence has increased in younger AI/AN people, both pregestational diabetes (PGDM) and gestational diabetes (GDM) have also increased significantly. Hyperglycemia during pregnancy can be associated with morbidity and mortality for both the mother and her infant. Therefore, management of diabetes in pregnancy offers a unique opportunity to affect both patients’ health positively. Currently, women with diabetes and good glycemic control can look forward to pregnancy outcomes that are comparable to that of the general population.
Screening and Counseling for Women with Diabetes during Reproductive Years
Ask about reproductive intentions/assess contraception.
At diagnosis, and then every visit
Provide preconception counseling and assessment.
3-4 months prior to conception
Screen for undiagnosed type 2 diabetes in pregnant AI/AN women (PGDM).
At first prenatal visit
Screen for GDM in all women not known to have diabetes.
• Precontraception Care - Pregnancy Planning and Type 2 Diabetes
Recommendations for Preconception Care
Inform women that risk is minimized with optimal glycemic control prior to conception, and that glycemic targets are stricter in pregnancy: fasting BG, 65-95 mg/dL; 1 h BG, 100-129 mg/dL; 2 h BG < 120 mg/dL, A1C < 6.0%.
Women with diabetes who are contemplating pregnancy should be evaluated, and, if indicated, treated for diabetic retinopathy, nephropathy, neuropathy, and cardiovascular disease.
Evaluate medications prior to conception and switch to only those approved for use during pregnancy.
Discuss importance of optimal nutrition, folic acid supplementation, and tobacco/alcohol/substance use cessation.
Consult or refer to multidisciplinary team (e.g., CDE, dietitian) experienced in caring for pregnant women with diabetes.
Pregnancy in women with pregestational diabetes (PGDM) is associated with an increase in risk to both the fetus and the mother. In women with poor glycemic control, the incidence of congenital anomalies and spontaneous abortions increases during the period of fetal organogenesis. A woman may not know she is pregnant during fetal organogenesis, which is not complete until 8 weeks post-conception.
Preconception counseling and planning are essential in women of childbearing age who have type 2 diabetes to optimize their diabetes control before becoming pregnant. It is important to discuss with women who are contemplating pregnancy the need for preparation prior to conception, including excellent glycemic control, use of pregnancy-approved medications, optimal nutrition, and abstinence from tobacco/alcohol/substance use.
Medications commonly used to treat diabetes and its complications may be contraindicated or not recommended in pregnancy, including statins, ACE inhibitors, ARBs, and noninsulin therapies. While there is some evidence supporting the use of glyburide and metformin in gestational diabetes, the ADA and the American College of Obstetrics and Gynecology (ACOG) both have recommended that further study be completed before their use can be supported in pregnancy. Insulin therapy should remain the recommended and preferred treatment for diabetes in pregnancy.
Recommendations for Screening for Diabetes during Pregnancy
Screen women without known diabetes at their initial prenatal visit to assess for PGDM:
If the patient is fasting, obtain:
Fasting plasma glucose, A1C;
If the patient is not fasting, then obtain:
A1C, random plasma glucose.
Screen for GDM at 24 to 28 weeks gestation in patients without PGDM using either:
Fasting 75 gram, 2-hour OGTT (ADA/IADPSG), or
Non-fasting 50 gram 1-hour oral glucose tolerance test (OGTT). If abnormal, then follow with a fasting 100 gram, 3-hour OGTT (ACOG).
Patients with a pre-existing diagnosis of type 1 or 2 diabetes do not require diabetes testing. All other patients should be screened at their initial prenatal visit to assess for previously undetected overt diabetes (PGDM) as defined by the criteria listed in the table below.
Diagnosis of Overt Diabetes in Pregnancy (IADPSG 2010)
Measure of Glycemia
Fasting Plasma Glucose (FPG)
≥ 126 mg/dL
≥ 92 mg/dL but < 126 mg/dL
< 92 mg/dL
Diagnose type 2 diabetes.
Test for GDM 24-28 weeks.
Hemoglobin A1C (A1C)
Diagnose type 2 diabetes.
Perform FPG for type 2 or GDM diagnosis.
Random plasma glucose
≥ 200 mg/dL + confirmation
Confirm with FPG or A1C above threshold to diagnose type 2 diabetes.
Currently, there is a lack of consensus among major guideline-setting organizations as to the optimal screening protocol for GDM. Two testing protocols shown in the table below are acceptable for screening for GDM:
Perform a fasting 75-g OGTT, with plasma glucose measurement fasting, and at 1 and 2 h, at 24-28 weeks of gestation in women not previously diagnosed with overt diabetes.
The OGTT should be performed in the morning after an overnight fast of at least 8 h.
The diagnosis of GDM is made when any of the following
plasma glucose values are exceeded:
Fasting ≥ 92 mg/dL (5.1 mmol/l)
1 h ≥ 180 mg/dL (10.0 mmol/l)
2 h ≥ 153 mg/dL (8.5 mmol/l)
Step 1. At 24-28 weeks, perform a screening, non-fasting 50-g glucose challenge. If 1 h value exceeds chosen threshold is ≥ 130 or ≥ 140 mg/dL, go to step 2.
Step 2. Perform a diagnostic fasting 100-g OGTT. Either the plasma or serum glucose level established by Carpenter and Coustan or the plasma level designated by the National Diabetes Data Group are appropriate to use. A diabetes diagnosis requires that two or more thresholds be met or exceeded. One abnormal value equals carbohydrate intolerance.
Plasma or Serum Glucose Level, Carpenter and Coustan Conversion
Plasma Level, National Diabetes Data Group Conversion
• Postpartum Screening for Type 2 Diabetes in Women with Previous GDM
Recommendations for Postpartum Diabetes Screening
Women with previous GDM should be tested postpartum using a fasting 75 gram 2-hour OGTT at 6-12 weeks post-delivery to determine their glycemic status.
Providers should monitor blood glucose in the postpartum and lactating period as clinically appropriate.
Women with a normal postpartum OGTT should be re-tested every 1 to 3 years with fasting blood glucose and/or A1C.
Women with GDM are at increased risk of developing type 2 diabetes after delivery. About one-third of all AI/AN women with GDM will develop diabetes within 5 years of delivery. All women with a history of GDM should receive counseling and education regarding lifestyle modifications that will reduce or delay the development of type 2 diabetes. Moreover, the importance of maintaining optimal glucose control prior to and during any subsequent pregnancy should be stressed. Women with a history of diabetes in pregnancy can be offered all standard Food and Drug Administration-approved contraceptive agents. Mothers also should be made aware that children of GDM pregnancies should be monitored for obesity and abnormalities of glucose utilization.
Care of Older Adults and Patients with Multiple Comorbidities
Recommendations for Care of Older Adults and Patients with Multiple Comorbidities
For elders with limited comorbidities, significant life expectancies, and good functional abilities, treatment targets may be similar to those for younger patients, with the caution that older patients often do not tolerate hypoglycemia well.
For frail elders and patients with multiple comorbid conditions, treatment targets should be selected cautiously, balancing the benefits of tighter control with the risks (e.g., hypoglycemia, hypotension, etc.) posed to them by the multiple medications required to achieve these targets:
Assess patients for fall risk, cognitive impairment, depression, urinary difficulties, and chronic pain,
Ask about social and functional support, financial resources, access to nutritious foods, etc., and
Refer for evaluation/intervention as needed.
Older adults differ markedly in their functional abilities, level of diabetes complications, and other comorbidities, life expectancies, and level and type of social and financial resources. Older adults with diabetes are more likely than those without diabetes to develop geriatric-related difficulties, including depression, cognitive impairment, urinary incontinence, falls causing injury, and pain syndromes. All of these issues should be factored in as providers and patients set diabetes-related treatment targets.
For elders with recent onset of diabetes and/or limited complications, significant life expectancies, and good functional abilities, treatment targets will be similar to those for younger patients. However, for frail elders and patients whose bodies are older than their chronological ages due to multiple comorbid conditions, treatment targets should be selected cautiously – to balance the benefits of reasonable control of specific targets with the risks posed by the multiple medications required to achieve these targets. Further, the particular medications selected need to be considered for both their individual effects as well as their interactions with the patient’s other medications, disease conditions, and overall quality of life.
As diabetes has been diagnosed in younger AI/AN people over the last few decades, more patients are living with diabetes longer, and consequently developing multiple diabetes complications during what is usually considered middle life. This trend has many implications for these patients – for their physical health as well as their mental health and the ability to function effectively in their many life roles (e.g., as parents, employees, caregivers to elderly parents, community members, etc.). Providers who get to know their patients, their families, and their life contexts can address their patients’ medical concerns while helping them to enjoy the highest possible quality of life for many years to come.
Designed for providers to engage women with gestational diabetes in conversations about self-care in small groups. Kit includes a facilitator guide, a 3’ by 5’ colorful tabletop map, and cards to engage women in conversations about their self-care. Providers must receive face-to-face training to use and obtain the maps and facilitator kit.