1) When to initiate insulin

A) Type 1 diabetes

• Start insulin immediately at diagnosis (basal + prandial, or pump/automated delivery).

B) Type 2 diabetes

1. Marked hyperglycemia/catabolism
   • A1c very high (commonly >10%) or severe symptomatic hyperglycemia
   • Weight loss, ketosis, polyuria/polydipsia
2. Failure of non-insulin therapy despite adherence and titration
3. Contraindication/intolerance to other agents
4. Acute settings: hospitalization, surgery, severe infection, pregnancy-related need, steroid-induced severe hyperglycemia

2) Choosing initial insulin strategy

Core insulin categories

• Basal: glargine, detemir, degludec, NPH
• Prandial (bolus): lispro, aspart, glulisine, regular
• Premix: e.g., 70/30, 75/25 (fixed basal+bolus proportions)

Quick regimen selection

3) Starting doses and titration (practical)

A) T2D basal start

• 10 units nightly, or
• 0.1-0.2 U/kg/day (higher end if very elevated glucose)

• If above target: +2 units (or +10-15%)
• If hypoglycemia: reduce by 10-20% and evaluate cause

B) When basal alone is not enough

• Basal dose creeping high (roughly >0.5 U/kg/day) with A1c still above goal
• Fasting near target but postprandial spikes persist Then intensify by:

1. Add GLP-1 RA (if appropriate/available), or
2. Add bolus insulin before largest meal (basal-plus), then progress to more meals, or
3. Switch to premix if simpler routine needed

C) T1D total daily dose concepts

• Typical initial TDD ~0.4-0.6 U/kg/day (individualize)
• Basal often ~40-50% of TDD (AACE care plan update, p.61)
• Carbohydrate ratio and correction factor are individualized:
  • I:C starting estimate often via 500 rule (rapid insulin)
  • Correction via 1800 rule (rapid insulin)
  • Then adjust empirically

4) What to do if initial insulin therapy does not work

1. Confirm true treatment failure
   • Check SMBG/CGM patterns (fasting vs post-meal vs nocturnal)
   • Verify A1c timeline (allow enough time for effect)
2. Rule out pseudo-failure
   • Missed doses, wrong timing, poor injection technique/site issues
   • Insulin storage problems, expired insulin
   • Cost/access barriers, fear of hypoglycemia
   • Diet mismatch, variable carbs, steroid use, intercurrent illness
3. Pattern-based adjustment
   • Fasting high -> adjust basal
   • Post-meal high with fasting at goal -> add/intensify mealtime insulin
   • Nocturnal lows + morning highs -> evaluate rebound vs dawn phenomenon
4. Escalate regimen
   • Basal -> basal-plus (1 meal) -> basal-bolus (multiple meals)
   • Or convert to premix BID/TID if adherence/simplicity is priority
   • Consider adding/optimizing non-insulin agents (especially GLP-1 RA/SGLT2 if suitable)
5. Safety review every step
   • Hypoglycemia episodes, renal/hepatic function, older/frail status
   • Individualize targets (less stringent for high hypo-risk patients)

5) Flowcharts

Flowchart 1: When to start insulin (T2D)

[Person with T2D]
        |
        v
[Assess severity: symptoms, weight loss, ketosis, A1c, glucose]
        |
        +--> If severe/symptomatic or A1c very high (e.g., >10%)
        |        |
        |        v
        |   [Start insulin now]
        |        |
        |        +--> Basal +/- immediate bolus (if very severe)
        |
        +--> If not severe
                 |
                 v
      [Optimize non-insulin therapy + lifestyle]
                 |
                 v
      [A1c above individualized goal despite optimization?]
                 |
          +------+------+
          |             |
         No            Yes
          |             |
          v             v
   [Continue]   [Start basal insulin]

Flowchart 2: Choosing insulin regimen

[Need insulin]
    |
    v
[Type 1?] --Yes--> [Basal-bolus or pump]
    |
   No (Type 2)
    |
    v
[Extreme hyperglycemia/symptoms?]
    |
  +---+---+
  |       |
 Yes      No
  |       |
  v       v
[Basal +  [Basal only start]
consider  |
bolus]    v
          [Titrate to fasting target]

Flowchart 3: If initial regimen fails

[Insulin started, goal not reached]
          |
          v
[Check adherence, injection technique, timing, storage, cost]
          |
          v
[Review SMBG/CGM pattern]
          |
  +-------+----------------------+
  |                              |
[Fasting high]          [Fasting at goal, post-meal high]
  |                              |
  v                              v
[Increase basal]          [Add/raise mealtime insulin]
  |                              |
  +---------------+--------------+
                  v
       [Still above goal or frequent hypo?]
                  |
           +------+------+
           |             |
          Yes            No
           |             |
           v             v
[Reassess targets, add GLP-1 RA,  [Continue + monitor]
switch to basal-bolus or premix,
address comorbidities]

6) Practical comparison of insulin options

1. a one-page clinic protocol (with dose-adjust table), and
2. a patient handout version (simpler language + self-titration instructions).

Insulin therapy guide: when to start, how to choose, and what to do next

1) When to initiate insulin

Type 1 diabetes

• Start insulin immediately at diagnosis.
• Standard: basal-bolus (multiple daily injections) or insulin pump.

Type 2 diabetes

1. Severe hyperglycemia (often A1c >10% and/or very high glucose)
2. Symptoms/catabolism: weight loss, polyuria, polydipsia, ketosis
3. Failure of non-insulin therapy despite proper use
4. Acute illness/hospitalization/surgery, pregnancy-related need, steroid-induced marked hyperglycemia

2) How to choose among insulin options

Insulin types

• Basal (long/intermediate): degludec, glargine U100/U300, detemir, NPH
• Bolus/prandial (rapid/short): lispro, aspart, glulisine, regular
• Premix: fixed combos (e.g., 70/30, 75/25)

First-choice by scenario

3) Starting doses (practical)

A) T2D basal initiation

• Start 10 units daily OR 0.1 to 0.2 U/kg/day
• Titrate every 3 to 7 days based on fasting glucose:
  • Above target: increase by 2 units (or 10 to 15%)
  • Hypoglycemia: reduce by 10 to 20% and evaluate cause

B) Add mealtime insulin (if basal not enough)

• Start with 4 units or 10% of basal dose before largest meal
• Titrate by 1 to 2 units every few days based on post-meal/pre-next meal glucose
• If still uncontrolled, progress to 2 meals, then 3 meals (full basal-bolus)

C) Premix option

• Often start 0.3 to 0.5 U/kg/day, split before breakfast and dinner
• Useful for consistent meal timings; less flexible

4) What if initial insulin therapy does not work

1. Adherence and technique
   • Missed doses, wrong timing, wrong injection site rotation
   • Storage/expired insulin
2. Pattern review (SMBG/CGM)
   • Fasting high -> basal issue
   • Post-meal high -> mealtime issue
3. Over-basalization check
   • Basal dose high (often >0.5 U/kg/day) but A1c still elevated
   • Suggests need for mealtime coverage, not more basal
4. Escalate rationally
   • Basal -> basal-plus -> basal-bolus
   • Or switch to premix if simpler routine improves adherence
5. Address contributors
   • Steroids, infection, diet mismatch, renal changes, hypoglycemia fear, cost barriers

5) Flowcharts

Flowchart 1: When to start insulin in T2D

[T2D patient]
     |
     v
[Assess severity: symptoms, weight loss, ketosis, A1c, glucose]
     |
     +--> Severe/symptomatic or very high A1c/glucose?
     |           |
     |          Yes
     |           v
     |   [Start insulin now: basal +/- bolus]
     |
     +--> No
             |
             v
   [Optimize non-insulin meds + lifestyle]
             |
             v
   [Still above individualized A1c goal?]
             |
         +---+---+
         |       |
        No      Yes
         |       |
         v       v
   [Continue] [Start basal insulin]

Flowchart 2: Regimen selection

[Need insulin]
    |
    v
[Type 1 diabetes?]
    |Yes --> [Basal-bolus or pump]
    |
   No (Type 2)
    |
    v
[Severe hyperglycemia/symptoms?]
    |Yes --> [Basal + consider immediate bolus]
    |
   No
    |
    v
[Start basal only]
    |
    v
[Titrate to fasting target]
    |
    v
[A1c still high with fasting at goal?]
    |Yes --> [Add mealtime insulin or consider premix]
    |No  --> [Continue current regimen]

Flowchart 3: If not controlled after start

[Insulin started, target not met]
          |
          v
[Check adherence + technique + storage + timing]
          |
          v
[Review glucose pattern]
   |                         |
   v                         v
[Fasting high]          [Post-meal high]
   |                         |
   v                         v
[Increase basal]       [Add/intensify bolus]
          \             /
           \           /
            v         v
        [Reassess in 1-2 weeks]
                |
                v
      [If persistent: basal-plus -> basal-bolus
       or switch to premix; address barriers]

6) Worked examples

Example 1: T2D starting basal

• 62-year-old, weight 80 kg, A1c 10.8%, fasting glucose 230 mg/dL
• Start basal: choose 16 units nightly (0.2 U/kg)
• Home fasting target 80 to 130 mg/dL
• Titration rule: increase by 2 units every 3 days until fasting in target
• After 2 weeks: fasting 120 mg/dL but post-dinner 240 mg/dL, A1c still high trend
• Add bolus before dinner: 4 units rapid-acting
• Increase dinner bolus by 1 to 2 units every 3 days until post-meal improves

Example 2: Over-basalization

• On basal 54 units, weight 90 kg (~0.6 U/kg), fasting near target but A1c 8.9%
• Do not keep escalating basal
• Add mealtime insulin at largest meal (or consider GLP-1 RA if appropriate)

Example 3: T1D initial split

• 70 kg adult newly diagnosed T1D
• Initial TDD ~0.5 U/kg = 35 units/day
• Basal 40 to 50%: about 14 to 18 units basal
• Remaining 17 to 21 units divided as mealtime bolus using carb counting/correction factor and close follow-up

7) Quick insulin choice summary

• a printable titration sheet (day-by-day dose adjustment table), and
• a clinic-ready protocol separated into T1D, T2D outpatient, and inpatient insulin starts.

Practical guide to insulin initiation, selection, and escalation

1) When to initiate insulin

A. Type 1 diabetes

• Always start insulin immediately at diagnosis.

B. Type 2 diabetes

1. Marked hyperglycemia
   • Common trigger: A1c >10% or glucose persistently very high
2. Symptomatic hyperglycemia/catabolism
   • Polyuria, polydipsia, weight loss, ketosis
3. Failure of oral/non-insulin therapy despite good adherence
4. Acute clinical situations
   • Hospitalization, severe infection, surgery, steroid-induced severe hyperglycemia, pregnancy-related need

2) Glycemic values to use (FBS and RBS)

• FBS (fasting blood sugar) target: 80 to 130 mg/dL
• RBS / post-meal target (1.5 to 2 h after meal): usually <180 mg/dL

• FBS >130 mg/dL consistently -> basal insulin likely needs up-titration
• FBS at target but RBS >180 mg/dL -> postprandial control inadequate; add mealtime insulin
• FBS <80 mg/dL or any symptomatic hypo -> de-intensify insulin and reassess

3) How to choose from available insulin options

Insulin classes

1. Basal: degludec, glargine (U100/U300), detemir, NPH
2. Bolus/prandial: lispro, aspart, glulisine, regular
3. Premix: 70/30, 75/25, 50/50 (fixed basal+bolus combinations)

Choosing regimen

4) Starting doses and titration

A. T2D basal initiation

• Start: 10 units/day OR 0.1 to 0.2 U/kg/day
• Titrate every 3 to 7 days using FBS:
  • If FBS >130 mg/dL: +2 units (or +10 to 15%)
  • If FBS 80 to 130 mg/dL: keep dose
  • If FBS <80 mg/dL or hypo: reduce 10 to 20%

B. Add mealtime insulin if needed

• Start bolus: 4 units or 10% of basal dose before largest meal
• Titrate by 1 to 2 units every 3 days to get post-meal glucose <180 mg/dL
• If still uncontrolled: expand to 2 meals, then 3 meals (full basal-bolus)

C. Premix strategy

• Consider if simpler plan improves adherence
• Usually twice daily before breakfast and dinner
• Good for regular meal timing, less flexible for variable lifestyles

5) If initial insulin therapy does not work

1. Adherence: missed doses, wrong timing
2. Technique: injection site rotation, needle use, lipohypertrophy
3. Insulin quality: storage/expiry
4. Pattern analysis:
   • High FBS -> adjust basal
   • High RBS with good FBS -> add/intensify bolus
5. Over-basalization check:
   • Basal dose high (often >0.5 U/kg/day) + A1c still high -> need prandial strategy, not more basal
6. Contributors: steroids, infection, diet mismatch, cost barriers, hypo fear

6) Flowcharts

Flowchart 1: When to start insulin (T2D)

[T2D patient]
    |
    v
[Check A1c, FBS, RBS, symptoms]
    |
    +--> Severe symptoms/catabolism or very high glucose?
    |          |
    |         Yes
    |          v
    |   [Start insulin now: basal +/- bolus]
    |
    +--> No
           |
           v
 [Optimize non-insulin therapy + lifestyle]
           |
           v
 [Still above target (A1c/FBS/RBS)?]
           |
        +--+--+
        |     |
       No    Yes
        |     |
        v     v
   [Continue] [Start basal insulin]

Flowchart 2: Using FBS/RBS to intensify

[On basal insulin]
      |
      v
[Review 3-7 day glucose log]
      |
      +--> FBS >130 mg/dL?
      |         |
      |        Yes --> [Increase basal]
      |
      +--> FBS 80-130 mg/dL but RBS >180 mg/dL?
      |         |
      |        Yes --> [Add bolus at largest meal]
      |
      +--> FBS <80 mg/dL or hypoglycemia?
                |
               Yes --> [Reduce insulin, evaluate cause]

Flowchart 3: Escalation pathway

[Basal started]
    |
    v
[FBS target not reached] --> [Titrate basal]
    |
    v
[FBS at target but A1c/RBS high]
    |
    v
[Basal-plus (1 meal bolus)]
    |
    v
[Still high] --> [Basal-bolus (2-3 bolus doses)]
    |
    +--> Alternative: [Switch to premix BID if simpler]

7) Example with FBS and RBS values

Example: T2D patient

• Weight 75 kg, A1c 10.2%, FBS 210 mg/dL, RBS 320 mg/dL
• Start basal: 15 units at night (0.2 U/kg approx)

Home log and action

• Day 1 to 3 FBS: 198, 190, 184 -> increase to 17 units
• Day 4 to 6 FBS: 170, 162, 156 -> increase to 19 units
• Day 7 to 10 FBS: 138, 132, 128 -> keep 19 units
• Now FBS near target, but RBS remains 220 to 240 -> add 4 units rapid insulin before dinner
• Titrate dinner bolus by 1 to 2 units every 3 days until post-dinner glucose <180 mg/dL

1. a one-page printable protocol, and
2. a daily dose-adjustment chart (FBS/RBS-based titration table).