Untreated type 1 diabetes can be a fatal condition due to diabetic ketoacidosis. Poorly controlled type 1 diabetes is a risk factor for chronic complications such as blindness, renal failure, foot amputations, and heart attacks. Intensive glycemic control has been shown to decrease the incidence of microvascular and macrovascular disease, and the decreased incidence of macrovascular disease has been shown to persist for up to 30 years.[225]White NH, Sun W, Cleary PA, et al. Effect of prior intensive therapy in type 1 diabetes on 10-year progression of retinopathy in the DCCT/EDIC: comparison of adults and adolescents. Diabetes. 2010 May;59(5):1244-53.
http://diabetes.diabetesjournals.org/content/59/5/1244.long
http://www.ncbi.nlm.nih.gov/pubmed/20150283?tool=bestpractice.com
[226]Nathan DM, Genuth S, Lachin J; The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993 Sep 30;329(14):977-86.
https://www.nejm.org/doi/10.1056/NEJM199309303291401
http://www.ncbi.nlm.nih.gov/pubmed/8366922?tool=bestpractice.com
[227]Pop-Busui RL, Low PA, Waberski BH, et al. Effects of prior intensive insulin therapy on cardiac autonomic nervous system function in type 1 diabetes mellitus: the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study (DCCT/EDIC). Circulation. 2009 Jun 9;119(22):2886-93.
https://www.ahajournals.org/doi/full/10.1161/circulationaha.108.837369
http://www.ncbi.nlm.nih.gov/pubmed/19470886?tool=bestpractice.com
[228]Nathan DM, Zinman B, Cleary PA, et al; Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Research Group. Modern-day clinical course of type 1 diabetes mellitus after 30 years' duration: the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications and Pittsburgh Epidemiology of Diabetes Complications experience (1983-2005). Arch Intern Med. 2009 Jul 27;169(14):1307-16.
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/724752
http://www.ncbi.nlm.nih.gov/pubmed/19636033?tool=bestpractice.com
[229]Nathan DM, Cleary PA, Backlund JY, et al; Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study Research Group. Intensive diabetes treatment and cardiovascular disease in patients with type 1 diabetes. N Engl J Med. 2005 Dec 22;353(25):2643-53.
https://www.nejm.org/doi/10.1056/NEJMoa052187
http://www.ncbi.nlm.nih.gov/pubmed/16371630?tool=bestpractice.com
[230]Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) Study Research Group. Intensive diabetes treatment and cardiovascular outcomes in type 1 diabetes: the DCCT/EDIC Study 30-year follow-up. Diabetes Care. 2016 May;39(5):686-93.
http://care.diabetesjournals.org/content/39/5/686.long
http://www.ncbi.nlm.nih.gov/pubmed/26861924?tool=bestpractice.com
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How does intensive glucose control compare with conventional glucose control in adults with type 1 diabetes mellitus?/cca.html?targetUrl=https://cochranelibrary.com/cca/doi/10.1002/cca.1025/fullShow me the answer Even a few years of intensive glucose control translate to reduced rates of microvascular and macrovascular complications 10 years later.[226]Nathan DM, Genuth S, Lachin J; The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993 Sep 30;329(14):977-86.
https://www.nejm.org/doi/10.1056/NEJM199309303291401
http://www.ncbi.nlm.nih.gov/pubmed/8366922?tool=bestpractice.com
[231]Albers JW, Herman WH, Pop-Busui R, et al. Effect of prior intensive insulin treatment during the Diabetes Control and Complications Trial (DCCT) on peripheral neuropathy in type 1 diabetes during the Epidemiology of Diabetes Interventions and Complications (EDIC) Study. Diabetes Care. 2010 May;33(5):1090-6.
http://care.diabetesjournals.org/content/33/5/1090.long
http://www.ncbi.nlm.nih.gov/pubmed/20150297?tool=bestpractice.com
The American Diabetes Association and International Society for Pediatric and Adolescent Diabetes (ISPAD) recommend maintaining glycosylated hemoglobin (HbA1c) <7% (<53 mmol/mol) to prevent complications in most nonpregnant adults, adolescents, and children with type 1 diabetes.[1]American Diabetes Association. Standards of care in diabetes - 2025. Diabetes Care. 2025 Jan;48(1):S344-52.
https://diabetesjournals.org/care/issue/48/Supplement_1
Less stringent goals may be appropriate for very young children; some older adults; people with a history of severe or frequent hypoglycemia; and those with limited life expectancies, advanced microvascular or macrovascular complications, or comorbid conditions.[1]American Diabetes Association. Standards of care in diabetes - 2025. Diabetes Care. 2025 Jan;48(1):S344-52.
https://diabetesjournals.org/care/issue/48/Supplement_1
Between 2013 and 2022, pediatric registry data show that the proportion of patients achieving HbA1c targets of <7% (<53 mmol/mol) increased from 19% to 39%, parallel to increased use of diabetes technology.[232]Zimmermann AT, Lanzinger S, Kummernes SJ, et al. Treatment regimens and glycaemic outcomes in more than 100 000 children with type 1 diabetes (2013-22): a longitudinal analysis of data from paediatric diabetes registries. Lancet Diabetes Endocrinol. 2025 Jan;13(1):47-56.
http://www.ncbi.nlm.nih.gov/pubmed/39622257?tool=bestpractice.com
The proportion of participants with insulin pump use increased from 43% in 2013 to 60% in 2022 and the proportion using continuous glucose monitoring (CGM) increased from 19% in 2016 to 82% in 2022.[232]Zimmermann AT, Lanzinger S, Kummernes SJ, et al. Treatment regimens and glycaemic outcomes in more than 100 000 children with type 1 diabetes (2013-22): a longitudinal analysis of data from paediatric diabetes registries. Lancet Diabetes Endocrinol. 2025 Jan;13(1):47-56.
http://www.ncbi.nlm.nih.gov/pubmed/39622257?tool=bestpractice.com
Overall, cardiovascular disease is the major cause of death and a major cause of morbidity for patients with diabetes. One analysis of patients with type 1 diabetes diagnosed before the age of 15 years found that the leading cause of death before the age of 30 years was acute complications of diabetes. After the age of 30 years cardiovascular disease was predominant, although death attributable to acute complications was still important in this age-group.[233]Gagnum V, Stene LC, Jenssen TG, et al. Causes of death in childhood-onset type 1 diabetes: long-term follow-up. Diabet Med. 2017 Jan;34(1):56-63.
http://www.ncbi.nlm.nih.gov/pubmed/26996105?tool=bestpractice.com
Between 1990 and 2019, the age standardised prevalence of type 1 diabetes increased among older people ages ≥65 years, concomitant with a substantial decrease in associated mortality.[234]Yang K, Yang X, Jin C, et al. Global burden of type 1 diabetes in adults aged 65 years and older, 1990-2019: population based study. BMJ. 2024 Jun 12;385:e078432.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11167563
http://www.ncbi.nlm.nih.gov/pubmed/38866425?tool=bestpractice.com
The increasing numbers of older people with type 1 diabetes can be attributed to improvements in care that have extended their lifespan and highlight a need for clinical guidelines targeted to older adults with type 1 diabetes.[235]Harris E. Guidelines may fall short as more older adults live with type 1 diabetes. JAMA. 2024 Aug 6;332(5):363.
http://www.ncbi.nlm.nih.gov/pubmed/38995640?tool=bestpractice.com
Older adults with diabetes need increased caregiver input and have higher rates of functional disability, accelerated muscle loss, (e.g., hypertension, stroke, heart, and kidney disease), and premature death than those without diabetes.[1]American Diabetes Association. Standards of care in diabetes - 2025. Diabetes Care. 2025 Jan;48(1):S344-52.
https://diabetesjournals.org/care/issue/48/Supplement_1
They are also at increased risk for several common geriatric syndromes (e.g., cognitive impairment, depression, urinary incontinence, falls, persistent pain, and frailty).[1]American Diabetes Association. Standards of care in diabetes - 2025. Diabetes Care. 2025 Jan;48(1):S344-52.
https://diabetesjournals.org/care/issue/48/Supplement_1
They may be at higher risk of hypoglycemia for many reasons, including irregular meal intake, difficulties in performing complex self-care activities (e.g., glucose monitoring and insulin dose adjustment) due to cognitive and physical decline, and worsening kidney function.[1]American Diabetes Association. Standards of care in diabetes - 2025. Diabetes Care. 2025 Jan;48(1):S344-52.
https://diabetesjournals.org/care/issue/48/Supplement_1
While individuals of childbearing potential with diabetes are at a higher risk of miscarriage and having infants with major congenital malformations than the general population with careful planning and adequate treatment, most can have successful pregnancies.[156]McCance DR, Casey C. Type 1 Diabetes in pregnancy. Endocrinol Metab Clin North Am. 2019 Sep;48(3):495-509.
http://www.ncbi.nlm.nih.gov/pubmed/31345519?tool=bestpractice.com