This condition — the plain-language one-pager.

What is Type 1 Diabetes?Diagnosis

Type 1 Diabetes (T1D) is an autoimmune disease in which the body's immune system destroys the insulin-producing beta cells of the pancreas. Without insulin, blood glucose rises uncontrollably and the body cannot use food as fuel — without treatment, T1D is fatal. T1D is not preventable, not caused by lifestyle, and not the same disease as Type 2 Diabetes. The modern T1D toolkit (continuous glucose monitors (CGMs), insulin pumps, automated insulin delivery (AID) systems) has transformed daily life and dramatically reduced long-term complications.

• Diagnosis — Symptoms (polyuria, polydipsia, weight loss, fatigue, sometimes DKA) + elevated glucose + low/absent C-peptide + positive autoantibodies (GAD, IA-2, ZnT8, insulin). Most diagnosed in childhood/adolescence, but ~25% present as adults (LADA).
• Insulin is mandatory — Multiple daily injections (basal-bolus) or insulin pump. Modern analog insulins (glargine/degludec basal; lispro/aspart/glulisine bolus). Inhaled insulin (Afrezza) for selected patients.
• Continuous Glucose Monitor (CGM) — The single biggest behavior change in modern T1D. Real-time glucose, alerts, trend arrows. Time-in-range (TIR, 70-180 mg/dL) is now the headline metric — aim for >70%.
• Automated Insulin Delivery (AID) systems — "Hybrid closed-loop" pumps that auto-adjust basal insulin from CGM data. Tandem Control-IQ, Medtronic 780G, Omnipod 5, iLet, DIY systems. Real-world results approach the long-coveted "artificial pancreas."
• Long-term complications — Microvascular (retinopathy, nephropathy, neuropathy) and macrovascular (CAD, stroke, PAD) — same as T2D, with the added cardiovascular risk of childhood-onset disease. Aggressive glucose, BP, and lipid management is the program.

Time-in-range — the new HbA1cKnow your plan

For 30 years T1D was managed by HbA1c, a single number every 3 months. CGMs have changed that. Time-in-Range (TIR) — the percentage of time glucose is between 70 and 180 mg/dL — predicts complications better than HbA1c and gives you immediate feedback on every meal, exercise session, and dose adjustment.

• TIR target ≥70% for most adults; ≥50% for older adults / children with limited ability to detect lows.
• Time below range <4% total, <1% <54 mg/dL — hypoglycemia matters as much as hyperglycemia.
• Coefficient of Variation (CV) <36% — measures glucose stability, predicts hypoglycemia risk.
• Pump + CGM + AID if available — most adults benefit; pediatric and pregnancy use is established.
• Sick day rules — never skip basal insulin; check ketones; hydrate; correct doses every 2-3 hours; call for persistent vomiting or rising ketones.

Your daily Force FieldLive It

• Take your insulin every day, every dose — never skip basal, even when sick or not eating. Adjust bolus to carbs + activity + glucose.
• CGM as continuous as possible — wear it; act on alerts; review trend reports weekly.
• Time-in-range >70%; coefficient of variation <36%; minimize lows.
• Carb counting + insulin-to-carb ratio + correction factor — the foundation of mealtime dosing. Update with your team as needed.
• Glucagon (Baqsimi nasal, Gvoke pen) at home + travel — train family + housemates.
• Sick day rules — never skip basal; check ketones; hydrate; correct insulin every 2-3 hours; call for persistent vomiting or DKA signs.
• Annual screening — A1C, lipids, urine ACR, eye exam, foot exam, thyroid, celiac antibodies (T1D + thyroid + celiac is a common cluster).
• Cardiovascular risk reduction — BP <130/80 (often lower target), statin per ASCVD risk, no tobacco.
• Mental health — depression and "diabetes distress" are common; screen yearly; treat.
• Continuous learning — T1D tech evolves fast; pump + CGM + AID systems get better every year.

Red flags — call nowAction

• Call your clinic the same day for: new chest discomfort with exertion that goes away with rest (stable angina worth evaluating); a missed dose of antiplatelet or statin; medication side effects (muscle aches, bleeding, GI symptoms).
• Bring up at next visit: any change in exercise tolerance, lipid follow-up timing, BP log review, smoking-cessation support, depression screening, sleep concerns.