1. Boluses, basals and corrections – Getting the doses right Stephen W. Ponder MD, FAAP, CDE Scott & White Clinic Temple, Round Rock and College Station

2. Perfection (not possible) Reality (what IS possible) - = The diabetes care “Gap” Generally speaking, diabetes self care is the result of the “perfect” minus the “reality”. We can (at best) only control our “reality”. Perfection in diabetes self care is not possible. Therefore, we must try to accept the size of the gap. Gaps shrink and expand. So…by this thinking… are you OK with the current size of your “gap”?

3. Ponder’s Pumping Principles VII.Quality diabetes self-care is more about the PROCESS than it is about OUTCOMES VIII.Technology changes; people don’t IX.Self-consistency is a virtue X.Everyone’s blood sugar fluxes; seek out patterns in the chaos XI.Success is always a relative thing XII.Don’t ever be afraid to start over I.An insulin pump is no better or worse than the human being attached to it II.Master carb counting well BEFORE pumping III.Age is not a limiting factor for a pump IV.Garbage in, garbage out: beware of the “pump and dump” phenomenon V.The best pump doctor acts as a coach VI.Simple is a good place to start, but pumping skills MUST advance over time

4. Why should I care about after meal blood sugar levels?

5. 180 100 Pre-meal2 hr glucose 140 220 Pre-meal 7% 5% 6% 8% HbA1c Vascular system 95115? Postmeal Blood sugars, A1c and CV Risk Goal: improve post-meal control: BG < 180 mg/dl

6. Before meal sugarAfter meal sugar

7. 5 cardinal concepts to understand 1)Target (range) 2)Basal rate(s) 3)Insulin:CHO ratio(s) 4)Correction factor(s) 5)Insulin on board (IOB) A number or range Start with 1 rate Start with 1 I:CHO Start with 1 CF 3.5 to 5 hours (4)

8. Diabetes is best approached 1 day at a time

9. Diabetes care is a process, not an action It has purpose, meaning or direction It has a logical structure or order Steps are mostly measureable It has a goal, outcome or result

10. Duration Of Carb Action Or…UNDERSTAND YOUR TARGETS Most carbs have most of their affect within 1 to 2.5 hours But complex carbs are slowed down by their protein and fat content

11. Carb Counting Accounts for half the day’s control Accuracy allows boluses to match carbs for post-meal control and a significantly lower A1c Made easier with automatic carb bolus calculations by pump Always make an effort to estimate (if not count carbs)

12. D-teens count carbs POORLY 23%

13. TIP: A standing insulin dose (or regimen) is ALWAYS CHANGED LAST When troubleshooting a type 1 diabetes blood sugar problem First consider… – Food – Timing – Equipment BEFORE changing an insulin regimen

14. Why is the TDD so important? Total Daily Dose (TDD) 1800/TDD = correction 500/TDD = carb ratio TARGET BG Insulin on Board (IOB) (2-8 hours) ½ TDD/24 = basal rate

15. Average TDD insulin ranges by age and weight 0.6-0.8 U/kg/d (toddler) 0.8-1.0 U/kg/d (child) 1.0-1.2 U/kg/d (teen)

16. 60 units ~ 30 units divided as boluses 30 units as glargine 60 units 1800 rule 30 60 units 500 rule 8.3 ~ 10 Insulin to carbohydrate ratio TDD Correction factor (aka sensitivity factor) Basal-Bolus: Example Calculations Give dose at bedtime 10 – 10 – 10 + snacks OR…

17. Adjust The TDD For A High Avg. BG or A1C Example: someone with a TDD of 35 units and few lows. A1c = 9%, so more insulin is needed: about 3.2 units.

18. worksheet

19. J.F.7/6/01 8/7/89 8.0 49.7 7H14N 5H 9 Lantus 35 26.25 2613 1.08 1.0 26 19 69.2 75 1:20 100-150 7/7/01 Novolog

20. What is basal insulin? Maintains balance Minimizes drift/flux +/- 30 mg/dl over time Does not account for disruptive effect of snacks, activity or stress May change over time Usually 40-60% of TDD

21. What defines an effective basal insulin? (here’s a good visual)

22. Hints about basal insulin 50% Rule: basals usually make up 40 to 60% of an accurate Total Daily Dose Basal rates will be similar through the day, such as between 0.45 and 0.7, or between 1.0 and 1.4 Adjust a basal rate in small steps – 0.05 to 0.1 u/hr Change basals 3 to 8 hours before need arises

23. 0.75 U/hr Starting a basal rate B A S A L Example: Pre-pump TDD = 48 units 75% of 48 units = 36 units 50% of 36 units = 18 units 18 divided into 24 hours = 0.75 U/hr time

24. 0.75U/hr Basal rates 0.5 U/hr 1.0 U/hr Midnight 3 AM 6 AM B A S A L time Programmed for the “typical” day

25. Survey: number of basal rates used % www.insulin- pumpers.org N = 816

26. ~2AM - 4AM is the physiologic nadir for insulin ~ 40% of hypoglycemia occurs during sleep! Often asymptomatic! Breakfast Lunch Snack Supper Snack bolus 2 - 4 AM Breakfast 6 – 9 AM Snack

27. Can’t “target practice” without a target! Targets are specific numbers May vary based on time of day or other considerations Are mathematical guides only Must be reasonably set

28. “Practice approaches perfect”

29. Selecting a blood sugar target Upper and lower limits (range) Upper and lower limits (range) A specific number A specific number Individualized Individualized Achievable Achievable Adjustable Adjustable 100 mg/dl 120 mg/dl 130 mg/dl 140 mg/dl

30. Set your BG range 100-200 80-180 70-150 reasonable individualized

31. Two week pumper log sheet (complete the open spots) Influenced by basal Influenced by boluses Checks overnight basal(s)

32. What defines a correction? Correction: to bring something back into order or balance Diabetes: to lower (or raise) and out of range blood sugar level. Situational variables – Time – Quantity – Recent/impending actions Reproducibility? Evolving nature? Stock “correction”

33. 5 time 0.75 U/hr “Correction” dose B A S A L I N S U L I N............ 2 hours time 180 mg/dl 80 mg/dl 250 mg/dl 110 mg/dl Example: 1 to 25 Actual – target / 25 250 – 125 / 25 = 5 5 “Acceptable” = “target” +/- 30 mg/dl gluco se bolu s

34. What defines a meal dose? “Covers” the potential rise in sugar level after eating a meal. In non-D people, the 2 hour after meal BG is <140 mg/dl (by definition) Personal goals must be set by the patient/doc Tight coverage by insulin for changes in blood sugar in non-diabetic people

35. Insulin to carb ratio Based on the “500 Rule” 500 ÷ TDD = grams of carbs covered by 1 unit insulin Example: 500 ÷ 60 = 8.3 = ~ 8 Therefore: 1 unit for every 8 grams Easier: 1 unit for 7.5 gm or 2 for 15 grams 15 grams = 1 carbohydrate choice CH O I G Blood sugar level

36. 6 time 0.75 U/hr Insulin to Carb [I : CHO] ratio B A S A L I N S U L I N............ 2 hours time 180 mg/dl 80 mg/dl 125 mg/dl 150mg/ dl Example: 1 to 10 60 grams CHO / 10 60 / 10 = 6 6 “Acceptable” = “target” +/- 30 mg/dl gluco se bolu s CH O

37. Carb Ratio or Factor Carb factor – how many grams of carb are covered by 1 unit insulin Carb bolus is based on: Your carb factor How many grams of carbs you plan to eat Your BG allows a correction bolus determination Amount of BOB (IOB) still active (ALSO determined from BG!) A pump can determine the bolus needed for a meal when the carb count and the carb factor are accurate Visit your dietitian to learn!

38. Check Your Carb Boluses Does your carb factor work for LARGE meals? – half your weight (lbs) as grams of carb Are carb counts accurate? Are boluses given 20 min before meals when the glucose is normal? For frequent lows after meals –> raise carb factor # For frequent highs after meals –> lower carb factor #

39. An Accurate Carb Ratio or Factor: Returns the blood sugar:Returns the blood sugar: to within 30 mg/dl (1.7 mmol) of where it started to within 30 mg/dl (1.7 mmol) of where it started by the time selected for your duration of insulin action (DIA) by the time selected for your duration of insulin action (DIA) with no lows within 5 hours after carb bolus given with no lows within 5 hours after carb bolus given

40. Carb Bolus Varieties Normal carb bolus Normal carb bolus Bolus taken immediately – most meals Bolus taken immediately – most meals Extended or square wave bolus Extended or square wave bolus Bolus extended over time – gastroparesis, pizza Bolus extended over time – gastroparesis, pizza Combo or dual wave bolus Combo or dual wave bolus Some now, some later – bean burritos, al dente pastas and pizzas, Symlin Some now, some later – bean burritos, al dente pastas and pizzas, Symlin

41. 0.75 U/hr Unused insulin 7 Units 6 Units B A S A L time 6 Units 4-6 hours “Stacking effect”

42. Avoid Insulin Stacking The goal is to help patients prevent over-correcting Available scientific data says how much active insulin remains Current practices to avoid insulin “stacking” include: Crude formulas (ie. 25% per hour or 50% of usual) Crude strategies (ie. set a high Post-Prandial target BG)

43. Does blood sugar (yes or no) Carbs to be eaten (limited by ability to count carbs effectively) (counts, guesses, or doesn’t count at all) Insulin to carb ratio (uses or doesn’t use) Insulin dose (given by doc, guessed, or calculated) “Thinking like a pancreas” example Correction or sensitivity factor, includes target blood sugar (yes or no) 220 mg/dl 1 to 50 75 gm 1 to15 T = 120 2 units 5 units 7 units

44. Bolus Size (Relative To Wt) Affects The DIA Measured as units per kg(2.2 lb) Larger boluses have a longer duration of action. For 50 kg (110 lb) person: –0.3 u/kg = 15 u –15 u/kg = 7.5 u –0.075 u/kg = 3.75 u Becker et al. Diabetes. 2005; 54 (Suppl. 1): 1367P 4 hrs How long a bolus will lower the BG:

45. Recommendations For DIA Times DIAs on current pumps can be set from 2 to 8 hours. An inaccurate DIA can significantly impact control. Mudaliar et al: Diabetes Care, 22: 1501, 1999

46. Basal/Bolus Balance < 50% Basal~ 50% Basal> 50% Basal Duration < 5 yrs Thin Physically active High carb/low fat diet Most peopleDuration > 5 yrs Puberty Less active Insulin resistant Low carb diet

47. Stop Lows First Better control and more stability Mild lows cause followup lows Small epinephrine release makes muscles sensitive to insulin Can lead to another low as much as 36 hours after the first More carbs than usual are needed Severe lows cause highs Higher stress hormone release makes glucose rise for 6-10 hrs Excess carb intake leads to highs Boluses may be reduced/skipped More insulin than usual needed To stop lows, lower the TDD!!!

48. Benefits Of Frequent checking Breakfast 100 (5.6) 200 (11) 400 (22) 300 (17) DinnerLunchBed 1 test versus 7 tests a day

49. HbA1c=5.99+5.32 / (BGpd+1.39) Atlanta Diabetes Associates study: 378 patients sorted from a database of 591 Pumps=MM 511 or earlier BG Target=100 C peptide <0.1 Actual A1c Versus Testing Frequency Data From 378 People On Pumps ADA: < 7% AACE: < 6.5% P. Davidson et al: Diabetes 53 (suppl 2): abstract 430-P, 2004

50. Questions?