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Diabetes mellitus type 1

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Updated 2024 ADA guidelines for the diagnosis and management of diabetes mellitus type 1.



T1DM is an endocrine disorder characterized by T-cell mediated autoimmune destruction of insulin-producing beta cells in the pancreas, resulting in insulin deficiency with resultant hyperglycemia and a predisposition to ketoacidosis.
The cause of T1DM is mostly autoimmune destruction of beta cells of the pancreas (70-90%) and idiopathic (10-30%).
The annual incidence of T1DM in the US is 22.9 per 100,000 person-years.
Disease course
Environmental triggers in genetically predisposed people lead to the production of autoantibodies against insulin-producing islet beta cells of the pancreas resulting in autoimmune destruction of these cells. This leads to insulin insufficiency and overt hyperglycemia, T1DM and its complications, diabetic ketoacidosis, altered mental status, coma, and death.
Prognosis and risk of recurrence
On average, the life expectancy of a person with T1DM is approximately 12 years less than the general population.


Key sources

The following summarized guidelines for the evaluation and management of diabetes mellitus type 1 are prepared by our editorial team based on guidelines from the American Diabetes Association (ADA 2024), the European Society of Cardiology (ESC 2023), the European Society of Hypertension (ESH 2023), the Endocrine Society (ES 2022,2020,2016), the Kidney Disease: Improving Global Outcomes Foundation (KDIGO 2022,2020), the Society ...
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Screening and diagnosis

Indications for screening, T1DM: as per ADA 2024 guidelines, monitor patients with preclinical T1DM for disease progression using HbA1c approximately every 6 months and 75-g OGTT (fasting and 2-hour blood glucose) annually, modifying the frequency of monitoring based on individual risk assessment based on age, number, and type of autoantibodies, and glycemic metrics.
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  • Indications for screening (neonatal diabetes)

  • Indications for screening (MODY)

Classification and risk stratification

CVD risk assessment: as per ESC 2023 guidelines, consider using the Scottish/Swedish risk prediction model to estimate the 10-year CVD risk in patients with T1DM.

Diagnostic investigations

General principles: as per ADA 2024 guidelines, ensure a person-centered communication style using person-centered, culturally sensitive, and strength-based language and active listening, eliciting individual preferences and beliefs, and assessing literacy, numeracy, and potential barriers to care in order to optimize health outcomes and health-related QoL.
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  • HbA1c

  • Screening for hypertension

  • Screening for CVD

  • Screening for autoimmune thyroid disease

  • Screening for celiac disease

  • Screening for diabetic nephropathy

  • Screening for diabetic retinopathy

  • Screening for diabetic neuropathy

  • Screening for diabetic foot

  • Screening for anxiety and depression

  • Screening for sleep disorders

  • Screening for cognitive impairment

  • Screening for serious mental illness

  • Screening for disordered eating behavior

  • Screening for gastroparesis

Medical management

Glycemic targets: as per ADA 2024 guidelines, set an HbA1c goal of < 7% (< 53 mmol/mol) without significant hypoglycemia in many nonpregnant adult patients with diabetes.
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  • Insulin therapy (indications)

  • Insulin therapy (delivery systems)

  • Monoclonal antibodies

  • Management of hypoglycemia

  • Management of diabetic nephropathy (general principles)

  • Management of diabetic neuropathy

  • Management of diabetic foot

  • Management of hypertension (BP targets)

  • Management of hypertension (lifestyle modifications)

  • Management of hypertension (pharmacotherapy)

  • Management of CVD (general principles)

  • Management of CVD (antihypertensives)

  • Management of CVD (antiplatelets)

  • Management of CVD (revascularization)

  • Management of dyslipidemia (lifestyle modifications)

  • Management of dyslipidemia (statin therapy)

  • Management of dyslipidemia (non-statin lipid-lowering therapy)

  • Management of dyslipidemia (lipid profile monitoring)

  • Management of dyslipidemia (hypertriglyceridemia)

  • Management of diabetic nephropathy (smoking cessation)

  • Management of diabetic nephropathy (renin-angiotensin system inhibitors)

  • Management of diabetic nephropathy (kidney transplantation)

  • Management of diabetic retinopathy

Inpatient care

Management of hospitalized patients, general principles: as per ADA 2024 guidelines, ensure that institutions implement protocols using validated written or computerized provider order entry sets for the management of dysglycemia in the hospital (including emergency department, ICU and non-ICU wards, gynecology-obstetrics/delivery units, dialysis suites, and behavioral health units) allowing for a personalized approach, including glucose monitoring, insulin and/or noninsulin therapy, hypoglycemia management, diabetes self-management education, nutrition recommendations, and transitions of care.
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  • Management of hospitalized patients (HbA1C testing)

  • Management of hospitalized patients (glucose monitoring)

  • Management of hospitalized patients (insulin therapy)

  • Management of hospitalized patients (treatment targets)

  • Management of hospitalized patients (prevention of hypoglycemia)

  • Management of hospitalized patients (oral carbohydrate fluids)

Nonpharmacologic interventions

Smoking cessation
As per ADA 2024 guidelines:
Advise all patients with diabetes not to use cigarettes and other tobacco products or e-cigarettes.
Ask patients with diabetes about the use of cigarettes or other tobacco products as a routine component of diabetes care and education. Offer and refer for combination treatment consisting of both tobacco/smoking cessation counseling and pharmacological therapy if identified.

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  • Physical activity

  • Dietary modifications (general principles)

  • Dietary modifications (eating patterns)

  • Dietary modifications (carbohydrates)

  • Dietary modifications (fat)

  • Dietary modifications (nonnutritive sweeteners)

  • Dietary modifications (sodium)

  • Dietary modifications (micronutrients and supplements)

  • Dietary modifications (alcohol)

  • Psychosocial care

Specific circumstances

Elderly patients, screening for comorbidities: as per ADA 2024 guidelines, consider assessing medical, psychological, functional (self-management abilities), and social domains in older adults to provide a framework to determine goals and therapeutic approaches for diabetes management.
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  • Elderly patients (screening for hypoglycemia)

  • Elderly patients (treatment goals)

  • Elderly patients (lifestyle modifications)

  • Elderly patients (pharmacotherapy)

  • Elderly patients (residing in nursing facilities)

  • Elderly patients (end-of-life care)

  • Pregnant patients (preconception counseling and care)

  • Pregnant patients (nutrition)

  • Pregnant patients (glycemic targets)

  • Pregnant patients (management of preexisting diabetes)

  • Pregnant patients (management of gestational diabetes)

  • Pregnant patients (BP targets)

  • Pregnant patients (prevention of preeclampsia)

  • Pregnant patients (postpartum care)

  • Pediatric patients (screening for hypertension)

  • Pediatric patients (screening for dyslipidemia)

  • Pediatric patients (screening for autoimmune thyroid disease)

  • Pediatric patients (screening for celiac disease)

  • Pediatric patients (screening for diabetic nephropathy)

  • Pediatric patients (screening for diabetic retinopathy)

  • Pediatric patients (screening for diabetic foot)

  • Pediatric patients (glycemic targets)

  • Pediatric patients (glucose monitoring)

  • Pediatric patients (insulin delivery devices)

  • Pediatric patients (dietary modifications)

  • Pediatric patients (physical activity)

  • Pediatric patients (smoking cessation)

  • Pediatric patients (psychosocial care)

  • Pediatric patients (self-management counseling)

  • Pediatric patients (preconception counseling)

  • Pediatric patients (management of hypertension)

  • Pediatric patients (management of dyslipidemia)

  • Pediatric patients (management of diabetic nephropathy)

  • Pediatric patients (transition to adult care)

  • Patients with COVID-19 infection

Patient education

Self-management counseling: as per ADA 2024 guidelines, encourage strongly all patients with diabetes to participate in diabetes self-management education and support to facilitate informed decision-making, self-care behaviors, problem-solving, and active collaboration with the healthcare team.
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Preventative measures

Routine immunizations: as per ADA 2024 guidelines, provide routine immunizations in pediatric and adult patients with diabetes as indicated by age.

Follow-up and surveillance

Treatment monitoring: as per ADA 2024 guidelines, include most components of the initial comprehensive medical evaluation in the follow-up visit.
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  • Continuous glucose monitoring

  • Monitoring of glycemic status

Quality improvement

Health promotion: as per ADA 2024 guidelines, ensure that treatment decisions are timely, rely on evidence-based guidelines, capture key elements within the social determinants of health, and are made collaboratively with patients and their care partners based on individual preferences, prognoses, comorbidities, and informed financial considerations.
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  • Use of diabetes technology